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462dsp/FM - Solidyne

1. 05 ROCK This adjustment prints a remarkable processing to music The gain of the AGC is around 9 dB which that considers a strong processing The force of this preset is sustained not only by the AGC output level but also by the fact that all the bands have slow attack times and fast recovery times By such reason the fifth band of highs post processing will have noticeable incidence on the processing When all bands have fast recovery times the action of the attack times prints force to the sound given punch to the music This is because being fast the recovery the next impulse finds released the compressor and this will take time again in containing the signal which lasts the attack time This effect is more notable in LF and as it is explained in the POP Page 17 adjustment one of the keys to obtain forceful pumping bass drums or beats for techno music The density EQ reinforces the lows slightly The marked attenuation in highs looks for to control the ear fatigue produced by the electrical guitars which can present high distortion intentionally applied of course whose density in bands M2 and HF usually is critical Remember that the previous compression stages are of hard processing Very low frequencies get a punch with the Bass Clipper control at 4 3 dB 06 ROCK LATINO This adjustment was thought for Rock and Pop music with strong presence of Indo afro Lat
2. Inputs and outputs are electronically balanced The inputs are bridging type with impedance greater than 10 KOhms The connectors used as is standard are female XLR 3 for the inputs and male for the outputs Take specially care with the phase e Use one pair shielded audio cables of GOOD QUALITY preferably with double shielding The maximum length recommended is 30 meters although in special cases it is possible to achieve 100 meters accepting a little loss at high frequencies e The connection of this cables are made as is standard See the following table Balanced input output connections 1 GND 2 balanced positive phase 3 balanced negative phase Unbalanced connection Inputs Signal 2 Ground joint 1 and 3 Outputs Signal to pin 2 leave pin 3 unconnected Ground pin 1 Page 9 2 4 Digital audio connections Optionally the processor has digital AES 3 inputs outputs models 462dsp AES The digital input supports Resolution 16 24 bits Sample rate 30 KHz a 96 KHz Internally 462dsp works at 24 bits 192 KHz the digital signal is converted internally by a stage called Resampler When the digital input is used is convenient to connect the analogical input too In case of losing the digital connection the processor switches automatically to the analogical inputs The input mode is selected from the main menu choosing the option Setup Input
3. Password turning the JOG and touch it briefly to confirm e A flashing cursor appears to enter the first character Turn the JOG until reach the wanted symbol and confirm with brief touch The cursor will jump to the next character e Proceed in the same way to choose the others characters e After confirm the last character the option OK is on focus PRESS AND HOLD to confirm the password A brief touch in this point will make jump the cursor to the first character again e Press and hold the JOG cancels the process in any instance equivalent to escape except when OK is selected in such case confirm the password e To delete the password edit it entering 3 space characters Write down the password in a secure place in order to do not loose it If you forgot the z password please contact with Solidyne and y you will receive instructions to restore it PROCESSOR MODE Shows the processor type The unit can be prepared for FM or AM stations This is defined in factory because requires some internal changes in the circuit board as well as a different programming of the flash memory with the corresponding constants for the AM band SOLIDYNE 462dsp broadcast digital processor Chapter 4 Audio processing settings 4 1 PROGRAM SELECTION The unit has 15 default programs 00 to 14 and 15 user memories The programs selects from the main screen Turn the JOG to expl
4. 60 dB at 19 kHz 15 kHz active FDNR filter 5 poles elliptical 0 003 at 1 kHz 95 dBA or better Ref 100 modulation 75 dB at 400 Hz gt 65 dB 30 15 000 Hz Main to sub amp sub to main due to amplitude and phase nonlinearities of left and right channels 30 15 000 Hz 65 dB minimum below 100 modulation 75 dB minimum below 100 modulation 75 dB minimum below 100 modulation 75 dB minimum below 100 modulation Adjusted 7 12 from rear panel preset control 70 dB at 19 Khz gt 60 dB 0 05 Hz 0 to 50 C SOLIDYNE 462dsp broadcast digital processor
5. Start and the coil in parallel to the tally light The relay coil voltage depends on the A voltage gives by the console When the relay receives tension the contact is closed activating the Mic Start function in the processor The voice s program remains active while the contact is closed This feature comes disabled from factory In order to use it you must enable the option MIC PROCESSING in the processor setup see 3 2 3 Processor Setup 2 6 MPX output The MPX cable will be a RG 59 coaxial 75 ohms like the used for CATV The output connector is BNC type The maximum length recommended for this cable is 25 m Take care with the grounding although this rarely is cause of problems because all Solidyne processors have MPX differential outputs that is to say with the Earth isolated of the cabinet to avoid ground loops If some residual humming appears when the system is on the air power off the processor If the humming disappears check the input connections at the processor If however the humming continues and only disappears unplugging the MPX cable this indicates some problem with the grounding When enters to the transmitter through the MPX input make sure that the internal preemphasis network IS DISCONNECTED that is to say flat response from 20 to 100 KHz Contrary when use an external stereo coder make sure that the generator INCLUDES the preemphasis curve
6. your customized adjustment look for that preset that more approaches to the sound that you are looking for your radio and copy it to a free user memory Soon modify the preset values in the user memory To copy a program proceeds as following 4 3 1 COPY PROGRAM At the main menu enter to the option COPY PGM A screen will appear to define From JAZZ To TE TROCE LATINO a Source program From Number name of the program that you want to copy To select this option turns the JOG observes the arrow and touch it briefly to confirm Soon turns the JOG again to explore the programs and touch briefly to confirm b Destiny program To Number name of destiny program To change it proceed like in the previous step In order to confirm the action turn the JOG to select Copy and touch it briefly The processor remains in the present program In order to load the copied program you needs select it from the main screen possible to recover it Default presets cannot Once a user program is overwritten is not be changed by any error of use 4 3 2 EDIT PROGRAMS From this option you accede to the heart of the processor You can edit the processing values for anyone user program Selecting this option you enter to the program edition screen described next TIPS To people who do not have time to fit and to hear carefully the Radio throughout several days we recomme
7. 1 pixel from the maximum xw Check that increasing the input level until 10dbm the VUmeters at full scale At this value the warning OVL must appear under the Vumeters In the oscilloscope you must observe a perfect sinus wave d xw Increase the input signal in step of 1dB until 18dbm At this value the signal at the output must be seen distorted clipped by the input stage e gt Check that previous distortion happens just at 18dbm at the other channel 7 1 2 Checking the OUTPUT LEVELS Input Audio generator at 1KHz on both input channels adjust the AGC so it compress 15db Output Connect a dB meter on left audio output XLR Procedure a Select the program N 26 b Under this conditions the audio output Hill must be 4dbm c Repeat for the other channel SOLIDYNE 462dsp broadcast digital processor 7 1 3 FREQUENCY RESPONSE Input Audio generator at 1 KHz on both input channels the amplitude is varied throughout the test Output Connect a dB meter to the left audio output XLR Procedure a Select the el program N 27 b Enter with a sine wave and adjust its amplitude so that the AGC compress exactly 30 dB waiting around 10 second to the AGC stabilized c Disconnect abruptly the source of signal HOLD Hill appears on screen Verify throughout this test that this legend do not disappear at any moment d Make a frequency sweep with an amplitude 25 dB un
8. 13 3 2 INSTALLATION SETTINGS neee 14 3 2 1 INPUT 14 INPUT SELECTION 14 INPUT LEVEL 15 3220UTPUT SETUP rvan voorveren tronen aten al 3 2 2 1 Adjusting the 100 of modulaci n in FM transmitters 15 3 2 3 PROCESSOR SETUP cia en 16 3 24 Notes bout FM 15 Chapter 4 Processing adjustments 41 PROGRAM SELECTION nennen 17 42 DEFAULT PROGRAMS vices 17 43 USER PROGRAMG 19 4 3 1 COPY PROGRAM 19 4 3 2 EDIT PROGRAMS 19 4 4 PROGRAM AD USTMENTS 19 4 4 1 PROGRAM NAME 20 4 4 2 EXPANDER AGC 4 4 2 1 AGC OUT GAIN 4 4 2 2 AGC attack time 4 4 2 3 AGC recovery time 20 EE KON o ne 21 4 4 3 MULTIBAND COMPRESSOR 21 4 4 3 1 Atack 22 SOLIDYNE 462dsp broadcast digital processor Chapter 6 audio prosessing for broadcasting vss ZTA briefly his tol ee is 25 2 2 Solidyne 462dsp psycho acoustic digital processor 27 2251 Blocks di Maida aaa 27 2 2 24 BITS 192 KHZ CONVERTER 27 Digital Input 27 223 PEAK SIMETRIZER 27 2 2 3 SUBSONIC PHILTER 28 2 2 4 LINEAR EXPANDER 28 2 2 5 GATEDAGG aaa 29 2 2 7 MULTIBAND COMPRESSOR 29 2 2 6 DENSITY ECUALIZER 30 227 IM CANCELLED CLIPPER 30 2 2 8
9. PC computer using the 462dsp serial port RS232 serial port It can be connected to USB bus with optional external adapter Optional Ethernet bus connection MPX processing for stereo interleaving allows for 130 L R audio level at 100 modulation Yes It includes free Windows 2000 XP software The user can change the processor s AM FM firmware chips Only two socket mounted Flash EPROM IC s have to be replaced Stereo coder is a separate module Five processing bands Nine processing stages Blue color LCD display with backlight Graphic type Resolution 240 x 64 Optional built in RDS encoder 90 127V and 190 230V 50 60 Hz selectable from rear panel 483 mm Wide 240 mm Deep 88 mm High Page 37 Page 38 SC 100 Digital Stereo Generator 16x Oversampling Very Low Distortion Audio Input mpedance Audio Input Level MPX Output Composite Output Level Frequency Response Audio I nput Filtering Total Distortion Signal to Noise Ratio Stereo Separation Crosstalk 38 kHz Suppression 57 76 and 95 kHz Suppression 76 kHz Sideband Suppression Pilot Level Pilot Protection RDS channel protection Pilot Stability 600 5 kOhms 1 5 Vrms for 5 Vpp at MPX out 400 Hz Differential output BNC connector floating ground 50 ohms Allows 45 dB canceling buzz amp noise due to ground loops 2 5 5 Volts pp adjustable from LCD display 20 14 000 Hz 0 1 dB Elliptical low pass filter 1 dB at 15 kHz
10. Pressing and holding the J OG around one second go to the main menu Each screen graphically indicates the actions available with the OG see figure The default input level is 4 dBu If your console manages a different level you must adjust the processor input level Press briefly the J OG to enter to the main menu Choose the option Setup Input and adjust the level according to the nominal specified on your console Your radio already is on the air with the sound of the Solidyne 462dsp At this point you must be anxious to listen what 462dsp is able to do with the sound of your radio on the air to begin we will explain briefly how to select the factory presets Tunes your radio in a good audio equipment and do the following Turn the JOG Note on the screen how the different presets programs names changes Pressing briefly the wheel load the program changing the processing and the sound on the air The 15 PRESET PROGRAMS can not be changed You have 15 USER MEMORIES to create your own adjustments You can start copying a preset program to a user memory and soon modifying it Page 5 1 2 Brief diagram for general connections 1 If your computer does not have serial port you can use a RS232 to USB adapter to connect the 462dsp on a USB port In units with option RDS you need to connect a computer to the processor for RDS programming This connection can be not permanent in case that a fixed text is
11. RDS PC connection For setup and control of RDS stage the 462 s RDS Data port must be connected to a computer using a standard COM RS 232 RDS Data PC 2 RxD 3 TxD 3 TxD 2 RxD 4 DTR 6 DSR 5 GND 5 GND 6 DSR 4 DTR 7 RTS 8 CTS 8 CTS 7 RTS Use a standard crossed serial cable as known as null modem Two female DB 9 connectors are required The following table shows the diagram of connection although only the connections emphasized in bold are needed The computer is used to transmit data to RDS coder These data can change in real time like SOLIDYNE 462dsp broadcast digital processor when the names of the songs are transmitted or can be a fixed text that it is stored in the internal memory of the RDS coder In order to command the RDS coder the software Solidyne Magic RDS is required This application is included in the 462dsp CD ROM provided with the unit Using this tool you will be able to start to send RDS data Please refer to the RDS help file for detailed information on the software 2 7 2 Connecting to the transmitter The models 462dsp RDS do not require a special connection MPX signal contains the RDS information that is injected directly to the transmitter when connecting the MPX output The digital signal that it contains information RDS is transmitted with a speed of 1187 5 bit s and modulates a subcarrier of 57 KHz using
12. characteristics of the sung voice differs remarkably from the spoken voice The multiband processing is moderate The AGC output is about 4 3 dB Greater values will cause very audible changes of timbre in some soloists due to the imbalance that take place between the bands with excessive compression The attack and recovery times stay relatively slow not to lose the dynamic profiles completely The mid bands M1 and M2 where the vocal energy is concentrated apply a considerable compression to the voice since their attack times are fast 17 mS and their recovery times are slow 540 mS and 181 mS respectively The adjustments of the density EQ compensate the balance between bands to obtain a flat response comparing the processed material with the original one For that reason band M1 that is the one that receives greater compression in average is emphasized not to lose presence the mid low 03 MELODIC HI BOOST This adjustment is similar to the previous one but can be said that a little hardest The high presence was increased releasing the attack 18 mS and lowering the recovery time 60 mS The mid low band M1 has a faster recovery time 400 mS and the low band is slightly more compressing The output level of the AGC was increased to 5 dB A bass punch is added setting the Bass Clipper control at 4 dB 04 MELODIC IMPACT This adjustment is similar to the previous one but with al little hard processing
13. designed for rack montage in standard racks of 19 requiring 2 rack height units If you prefers the processor can be placed on a table Four self adhesive rubber tops are given for this purpose When mounting start fitting the bottom screws and soon the superior ones Use flat screws with flexible o rings rubber PVC etc The frontal panel is made of aluminum so you must take special care of don t to apply excessive force on the screws since it can cause deformation or even break the angles of the panel Page 4 The unit cans wok with 110 or 220 VAC A voltage switch on the rear panel selects AC the correspondent voltage ALWAYS CHECK THIS SELECTOR Voltage BEFORE PLUG IN 4 CAUTION i E Or ne tm In order to reduce the risk of electrical shock do nat retire the covers of the cabinet The internal pieces do not require maintenance of the user Refer the technical maintenance to qualified personnel The power cord provided with the unit gives Earth return to the processor Do not replace it amp nor uses adapters MAKE SURE THAT HAVE WITH A GOOD GROUND TAKING The exclamation icon within a triangle that appears in this manual is for alerting to the user about the presence of important instructions on the operation and maintenance of the equipment Letter i within a circle that appears in this manual is for alerting to the user about the informatio
14. equalization curve compensates the response to obtain a cuasi flat curve Respect to the compressors the low band is freed to obtain great impact in the beats This is obtained with a slow attack time 49 mS and a fast recovery 340 mS In this way as the recovery of the compressor is fast each beat of big drum is affected by the attack time that lets pass the initial impulse of the wave This impulse that escapes is contained soon by other stages of the processor limiters But the result is a sensation of greater dynamic range If the recovery time for the band LF is slow the attacks of the successive beats would be squashed by the compressor the attack acts only on the first beat and never more which is equivalent to have an attack time equal to zero The high bands also are something released to obtain brightness and presence in trebles something of extreme importance in POP music usually strident cheers and up The Bass Clipper threshold is increased up to 3 5 dB 09 POP IMPACT Page 18 This is an adjustment for generic music The gain of the AGC is 6 dB and the BASS CLIP threshold is 4 dB to reinforcement the lows 10 CHILL OUT This can be considered a moderate processing Chill out makes reference to a calm music generally of electronic instrumentation By the nature of this music the commitment with the spectral balance is not capital that is to say there is m
15. in the musical instruments and its effect is highly disagreeable and irritating for the ear of the Page 30 audience For the exposed reasons considerable efforts in research have been made to obtain audio clippers in which the intermodulation is reduced or even better cancelled of being possible System RIMCA developed at the laboratories of Solidyne begins in a multiband clipper was a good solution used in analogical units The digital days In digital audio the adverse effects derivates of the clipping far from disappearing becomes more complexes DSP technology since works with digital signals has limitations in to manage nonlinear processes as it is the case of the clipping that it generates signals with very steep slopes These type of processes generates harmonic components of very high frequency that violate the condition of Nyquist degrading remarkably the final audio quality The conventional digital clipping techniques used by other marks work resampling the signal at greater sample rates thus to be able to reduce but to never eliminate to the distortion caused by the alias effect Although the result that is reached with these techniques is acceptable the collateral effects caused by digital clipping are diminished but not eradicated completely For this reason the laboratories of Solidyne continued developing new techniques After long investigation and numerous tests 462dsp took a s
16. that the compressor like undesired effect will increase At this point maybe you will be thinking that DOES NOT HAVE SENSE to make an expander of the signal and soon to compress it You will think perhaps that an effect cancels to the other But it s not true for two reasons First the different attack and recovery times Second multiband compressors have elevated threshold whereas the linear expander has a very low threshold and a linear behavior below the threshold It means that the actions do not cancel because both processes are not complementary The linear expander to optimize its behavior has instantaneous attack and a fast recovery times Here is where the psychoacoustic concept post pulse hearing inhibition is used This allows using an expander with a quick recovery time so that it s not perceived by the ear The broadband compressor that follows the expander has a very slow recovery time Therefore with impulsive signals as the audio program any cancellation effect occurs Another advantage of using a linear expander previous to the processing is that an excellent audible sensation of dynamic range is obtained In fact recent studies have demonstrated that the audible sensation produced by the level variations of an audio signal is related to the changes happened in the first 50 milliseconds and is little dependent of the reached final value This implies that an expander in the short term is perce
17. the method of Amplitude Modulation with suppressed carrier that is added to the multiplexed stereophonic signal that it is sent to the transmitter input See the blocks diagram shown in Chapter 1 Page 11 THIS PAGE HAS BEEN LEFT INTENSIONALL Y EMPTY Page 12 broadcast digital processor SOLIDYNE 462dsp Chapter 3 Starting up and operation 3 1 Basic actions 3 1 1 Using the JOG wheel All the installation settings and each parameter of audio processing are managed with the JOG wheel into a friendly graphic interface The frontal panel presents a big blue screen of dot matrix and a rotating control JOG with push button Their use is very simple e Turn the JOG control to select an option or to change values i e changing levels select Yes No etc e To confirm an option value press the JOG briefly It s like make click with the mouse e Push and hold the JOG by a second to enter to the Main Menu or to cancel a screen lt s the equivalent to double click with a mouse 3 1 2 Processing programs 462dsp has 15 presets programs and 15 user memories Programs from 00 to 14 are programs made by the engineers of Solidyne ready to be on the air There are different adjustments for different music s styles Each program has a name that identifies it Jazz Rock Pop Melodic etc but the names are only indicatives all music styles sounds well with any preset Processing programs are describe
18. time that you try to access to the main menu the processor will ask you for the password Note that you don t need the password to change the current preset on air Please see 3 2 3 Processor Setup SOLIDYNE 462dsp broadcast digital processor Page 13 3 2 INSTALLATION SETTINGS a On start up the 462dsp shows by a few seconds the boot screen indicating the firmware version SOLIDYNE PRO Wer 2 10 Booting 46205 Processor Once started the processor present the main screen described in the item 3 of the Chapter 1 amp The unit always starts loading the last used program b Pressing and holding the JOG you accede to the Main Menu Once into main menu turn the JOG until select the desired option The selected option is marked by a little arrow that appears below the icons Touch briefly the JOG to confirm the selection WARNING Remember that being in the main screen turning the JOG or touching it briefly you accede to the mode program selection In this mode turning the JOG you explore the 462 s programs In order to leave the programs selection mode press and hold the JOG In order to accede to the main menu press and hold again If being in the main menu or any settings screen changes not occur during 10 minutes the unit returns to the main screen discarding the changes 3 2 1 INPUT SETUP a Here you define the audio level and ty
19. transmitted it is stored into RDS memory 2 When the processor connects to the console using the digital inputs its convenient to make the analogical connection too In case of fault in the digital signal 462dsp changes to the analogical inputs automatically uy FM TRANSMITTER 17 PE 3 In this example a RF connection was used to transport the MPX signal from the processor to the transmitter which assumes installed in a build far from the studies MPX RF LINK 3 1 BNC to BNC cable Studio to Transmission Plant In other configurations the processor locates in the transmitting plant and a digital link is used to send the audio multiple sends can be used for backup RDS DATA 1 standad serial cable 462dsp RDS PG running DIGITAL AUDIO CONECTION In this case the remote control of 1 female XLR to male XLR 462dsp can be implemented through a data channel of the link that allows ANALOGICAL AUDIO CONECTION 2 sending RS 232 data 2 female XLR to male XLR On Air CONSOLE The progressive bars show the action of several 1 3 Understanding the main screen processor stages The name of the current Next you will see an overview on the 462dsp main screen Later each processing stages and its settings screens are fully analyzed When the unit starts up a boot screen appears showing the current version of the operating system Once started the unit presents the main screen wh
20. LOW PASS 15 KHz DIGITAL FILTER 2 2 9 DIGITAL STEREO CODER 2 2 10 MPX PROCESSING visits eens 31 Chapter 7 E Measurrements 33 71 33 7 1 1 Checking the INPUT LEVELS 33 7 1 2 Checking the OUTPUT LEVELS 71 3 FREQUENCY RESPONSE 33 aa 33 7 15 STEREO CROSTALK 34 1 56 ADISTORTION tend 34 73 5 100 STEREO CODER Fine calibration protocol 35 7 2 1 TEST POINTS DIAGRAM cor 35 7 2 2 ADJUST PILOT LEVEL w35 7 2 3 PILOT PHASE ADJ USTMENT a35 124 CHANNEL 5 36 7 2 5 MEASUREMENT OF RESIDUAL NOISE 36 7 2 6 AUDIO DISTORTION MEASUREMENTS en 36 Chapter 8 Technical specifications 37 Page 3 About this manual User s manual May 8 2007 ADVICES 462dsp firmware 2 1 All rights reserved No part of this manual can be reproduced be copied or be transmitted in any form or by no electronic or mechanical procedure or in its totality or partly What s in the box You must find the following components into the box 1 Solidyne 462dsp processor 1 user s manual 1 AC Interlock 1 CD ROM with VirtualRack 5 software 1 Guaranty certificate 4 self adhesive rubbers tops Please check when receive to verify that all components are okay About the montage 462dsp processors are
21. SSLIDYNE IGITAL POWER 3 de Febrero 3254 1429 Buenos Aires Argentina Phone 54 11 4702 0090 e mail info solidynepro com fax 54 11 4702 2375 web www SolidynePRO com 462dsp FuM 4 bands digital audio processor ser manual Last revision July 2007 P gina 2 procesador para radiodifusi n SOLIDYNE 462dsp Table of Contents Contents HOT AO 3 About this manual Whats in the 0 ADVICES oca Chapter 1 Quick installation guide 1 1 Basic connection and settings 1 2 Diagram of general 1 3 Understanding the main 5 Chapter 2 Advanced installation 2 1 1 POWER 9 LIMON Na 9 2 2 Analogical audio connections 2 3 Digital audio connections 10 2 4 Console 10 2 5 output 10 2 6 RDS CODER OPTIONAL 11 11 1 4 Chapter 5 Remote Control 5 2 Connectig to the P C n 23 2 6 1 RDS PC comnection 2 6 2 Connecting to the transmitter nennen enen 1 Chapter 3 Starting up and 13 3 1 BASIC aia 13 3 1 1 Using the JOG wheel 13 3 1 2 13 3 1 3 Control modes 13 3 1 4 Access PASS WOTO eins
22. This is thus since the 462dsp audio output DOES NOT INCLUDE preemphasis only the MPX output has preemphasis broadcast digital processor SOLIDYNE 462dsp 2 7 RDS CODER OPTIONAL SA Models 462dsp RDS have moloomassten internal RDS coder RDS Radio Data System is a system developed by the European Broadcasters Union EBU It allows adding to a conventional FM transmission additional information by means of the inclusion of sub carrier that contains data Their main applications are 1 The automatic tuning of the receiver to a radio network selected by the user which allows to listen to a program for example Classic Radio during a long trip by the route with no need to tune manually the receiver to another station of the same radio network when the reception happens to be deficient when leaving the zone on watch of a determined station 2 Show on the receiver screen the radio network name that is tuned for example Radio 1 and the kind of program the general news talk show sports music varieties monk etc 3 The automatic reception of information related to the traffic When this feature is selected the news has priority on the traffic so that the receiver will exchange automatically within a same network to the transmitter that emits information on the traffic and once finished this information it will return to be in tune automatically the transmitter that previously was selected 2 7 1
23. air Therefore we will have to listen carefully with a good receiver better still tuning Walkman or and an audio amplifier of high quality with good loudspeakers Not to listen the signal directly from the audio output of 462dsp but the air signal of the trasmisor 4 4 1 PROGRAM NAME Allows change the program name Press briefly on this option to enter to the edit mode AAA paralel mar TH ST ea SELECT CHARACTER JUCHAANGE POSITION f OK SELECT NEW PROGRAM JERS EDADES e The characters are changed turning the JOG To confirm press briefly the JOG e To confirm the changes press and hold on OK e To cancel and leave this screen press and hold on any character 4 4 2 EXPANDER AGC El EEE EEN GE GH 20 4 4 2 1 AGC OUT GAIN The output level of the AGC is a CRITICAL ADJUSTMENT since it determines the level with the signal reaches the multiband compressors and therefore the compression degree that will be applied So the action of the multiband compressors fits using the output level control of the AGC LOUDNESS BANDS indicators show the compression degree applied by the multiband system Each band has its own indicator Usual values for the AGC output are between 6 to 12 dB IN MIND e How much greater the compression degree is more loudness has the program on the air But high compression levels greater than 18
24. alanced input Z 110 ohms Automatic selection of 32 44 1 48 96 192 Khz with sample rate converter 128 dB Dynamic Range 117 dB THD to avoid jitter 600 balanced XLR output level 4 dBm Sigma Delta converters 24 bits 192 Khz Optional AES 3 digital balanced output Z 110 ohms FS 48 or 96 Khz selected by software From 2 Vpp to 5 Vpp in 0 2 steps DSP Digital Signal Processing Total CPU power 2 700 MIPS SuperModulation exclusive Solidyne technology at 608 Khz oversampling Fast clipper DC 10 Mhz wideband channel to avoid audible artifacts 20 15 000 Hz 0 25 dB Flat mode XLR out or digital AES 3 Out Output without pre emphasis THD below 0 008 30 15 Khz Flat Mode Dynamic Range 95 dBA 75 dBA 1 KHz gt 65 dBA 30 15 000 Hz Chebyshev FC 20 Hz 25 dB rejection at 10 Hz Phase processing technology with Kahn Bonello algorithms Cancelling Factor 8 1 Range 20 dB Attack amp Release time software controlled Range 30 dB Attack Release time Threshold controlled from LCD screen DSP controlled Five Bands Crossover 24dB oct Max compression 30dB Slope 10 1 Attack and Release controlled separately IM canceling factor greater than 30 dB below 250 Hz Four channels absolutely alias free using DC 10 Mhz bandwidth channel Four bands density equalizer with 15 dB range at the output of multiband compressors 15 Khz digital low pass FIR filter 60 dB rejection at 19 Khz 30 programs that can be changed on air from
25. anual f Now connect the sine wave generator at the same frequency and level to the Right Channel pin JS3 g Measure at the Belar the residual level of the Left channel Calibrate channel separation to the minimum Left level using P2 control More than 70 dB rejection is a correct figure h Verify channel separation at the 20 Hz 15 000 Hz range This must be better than 60 dB 65 dB typical Page 36 7 2 5 MEASUREMENT OF RESIDUAL NOISE Disconnect S1 and S3 from the Audio Processor Use a good Audio Voltmeter with A weighted filter connected at the Left and Right audio outputs of the BELAR modulation monitor Use as reference 4 Vpp sine wave Values better than 92 dBA must be measured 94 dBA is typical value 7 2 6 AUDIO DISTORTION MEASUREMENTS Connect a good distortion measurement set like System ONE Agilent 8903B or Sound Tech ST 1710A to the Left amp Right audio outputs of the BELAR set Values under 0 01 must be measured at 1 kHz Since Belar has it distortion floor at 0 01 in order to measure the real distortion of SC100 stereo coder is recommended to use a procedure not based on modulation monitors Proceed this way a Connect to ground Test Point TP1 in order to cancel 19 KHz Pilot b Then connect a very low distortion audio generator at both inputs S1 amp S3 This will cancel 38 Khz subcarrier Connect a good THD distortion measurement set at the MPX output of stereo coder Adjust to
26. as is explained later You can connect an S PDIF output to the AES3 input of 462dsp using an mmm S PDIF to AES 3 adapter The figure shows a compact adapter XLR BNC AES 3 output has a resolution of 24 bits with a samplerate selectable between 48 96 KHz see 3 2 2 Output Setup The connector is male XLR AES3 input and output cables connect as following XLR Signal 1 GND 2 AES3 1 3 AES 3 2 AES 3 standard connection 2 5 Console MICstart With the 462dsp the current processing program can changes when the study microphones activates In this way you can use a processing specially done for voices The default adjustment for voices is the program 09 Voice Impact Obviously you can copy and customize this program The commutation takes place when grounding the MICstart input When this happens the processor exchanges the program and the access from the JOG wheel is blocked When the MICStart input is opened 462dsp returns to the previous program Console MICstart uses a connector RCA type With consoles Solidyne 2300 series MICstart is Page 10 connected directly to the Digisolid output of a microphone channel please refers to the manual of the console In other consoles the control can be solved using the tally signal to activate a relay AL PROCESADOR mic start CUERPO TENSION DE CONSOLA Vee Connect the relay contact directly to the RGA MIG
27. ast to make level abrupt changes of level that can take place by shouts discussions or outbursts of laughter The speed of attack of the compressors must be fast to contain great impulses that take place in the beginnings of phrases when the compressors begin to work If the attack times are long can take place excessive processing and trim of the signal in certain entrances of the speaker in other words the speaker will sound saturated or dirty during a brief moment when he begins to speak On the recovery times there is more freedom reason why they will be fit according to the type of voices of the radio Like general rule remembers that long recovery times produce a smooth processing whereas with short times the loudness is increased but the processing becomes more heavy greater compression Respect to the gains the voices do not tolerate high multiband compression so if for music a strong adjustment is used for the voice the AGC output level will have to be located around 9 dB An excessive processing will sound disagreeable to the ear amp TAKE IN MIND e When creates your own adjustment for the voices considers that the equalizing does not have to be radically different to the used for music That is to say the voice impact program MUST BE CUSTOMIZED maintaining the equalization used for the music 4 3 USER PROGRAMS Default programs cannot be modified To make
28. at for certain musical styles The scales for attack times are different for each band In order to define the attack times you must consider the type of material to process Some musical styles like the rock amp pop tolerate a hard processing more clipping This offers a great sensation of dynamic range depth of the sound For orchestral music jazz piano agree to use faster attack times 4 4 3 2 Recovery times It s the time that the compressor takes in recovering its linearity as soon as the signal falls below the threshold The recovery times also are key settings to produce the perception of dynamic range In main lines if the recovery is slow the compressor practically works continuously and initial impulses produced by the attack time are lost That is to say the attack takes place the first time but as the compressor s gain does not recover the following attacks are fully compressed In this condition the attack time does not have any effect The attack time is responsible to generate sensation of dynamic range In percussion this is not desirable For example techno music requires short time of recovery time in the low band not to lose the attack of groove The compressor must recover so that each beat is affected by the attack time In the highs band the same occurs If the recovery time is very slow the attack does not take effect and the loudness of the high band a Hi Hat for example d
29. ay control select the MPX output to 4 peak to peak Comnect a sine wave generator at the LEFT input of the audio processor at 1 Khz 4 dBm output Verify that the output waveform looks like FIG 1 FIG 1 BASE BAND OUTPUT 1 KHZ LEFT CHANNEL IN IMAN Mi I ik INN i 1 2608 6 40008 MN 8 48008 1 2008 2 0000 8 8868 2 80E 83 a Replace the audio generator at the processors Left input for audio program music or voice Please carefully take note of this peak to peak value let name it Xpp SOLIDYNE 462dsp broadcast digital processor b Disconnect the audio program from the LEFT input and disconnect the ground of the test point TP1 Then the 19 Khz pilot tone will appear c With the oscilloscope measure the peak to peak value of the 19 Khz pilot tone let name it Ppp The percentage level of pilot tone will be Pilot Level 100 Ppp Xpp Using the control P4 adjust Ppp to the desired value normally 9 to 11 is a good value d Note If you have a Solidyne VA16 modulation monitor or BELAR FMS 2 measurement set you will be able to measure pilot tone level from on air transmission and you can correct it using P4 7 2 3 PILOT PHASE ADJUSTMENT This method is an absolute system not dependent from the calibration of the Modulation Monitor You will need a very good DC 20 Mhz oscilloscope Tektronix preferred with vertica
30. ay the Factory Calibration of our stereo coder do not change with the years Note 1 Previous to this adjustment the Pilot Phase item 2 must be adjusted Note 2 This calibration must be done with stereo coder inputs disconnected from audio processor Then it must be necessary to install a new flat cable connector set which avoids connection with audio processor and allows direct connection of the audio generator to JS1 and JS3 JS connector a Verify that the input stage bias is correct Use a DC millivoltimeter to check that voltage difference between TP2 R222 and TP3 R233 is less than 0 1 mV If not correct it using P1 Connect the BELAR measurement set to the MPX output connector Check the PHASE mode of the Belar You must get at least 65 dB rejection at 19 KHz pilot tone If not please make the Belar calibration procedure of PHASE see Belar manual Connect a sine wave generator at 400 Hz 1V RMS to the Left Input pin JS1 Leave disconnected the right input S3 b lt c e Measure channel separation at the Belar Right channel will be under 70 dB typical is 75 dB Correct the phase control of the Belar to improve this figure Calibrate channel separation to the minimum Right level using C1 trimmer at the low pass filter of SC100 More than 70 dB rejection is a correct figure If not make the complete procedure of channel separation calibration of the Belar set see Belar m
31. d with detail later You can customize the programs copying it to the user banks 15 to 29 and edit them By default user memories are empty strictly speaking with flat processing adjustments You can create a new adjustment changing the values of each parameter on the user memory or copying a preset to the user memory recommended See 4 3 1 Copy programs 3 1 3 Modes of control The processor can be controlled of many ways a Can be manually controlled from the frontal panel b The programs can be chosen automatically from the OnAir PC In this way you can use a specific processing for each song or musical style The programs can be created and edited using the 462dsp VirtualRack software This software allows saving the 462 s programs in the Hard Disk files 462 that you can send by mail so that other radios of your chain share the customized adjustments In addition this software allows creating scheduling programming to change the processing program at certain hours from the day Virtual Rack runs in background using very few resources In fact this software can run on the On Air computer d Connecting the PC to Internet you can controls the software via Shared desktop Windows feature 3 1 4 Access password You can define a password of 3 characters letters numbers and signs to avoid that non authorized people make changes on the programming adjustments Each
32. dB can produce a confused sound in certain type of music hyper processed of high density and excessive alteration of the timbre with soloists voices or instruments For this reason it s a critical adjustment and you must pay special attention to this control 4 4 2 2 AGC attack time The attack time is the time that the AGC takes to reduce its gain when the input signal increases Like general rule it can say that for voices short times of attack must be used 500 ms whereas for music longer times are preferred 3 to 4 seconds Note that when the input signal increases quickly during the AGC attack time the signal is contained by the multiband compressor that will act strongly until the AGC compensates their level Depending on the adjustments of the following stages a too slow attack of the AGC can cause an excessive compression of the signal mainly with voices 4 4 2 3 AGC recovery time When the input signal decreases the AGC begins to increase their gain to compensate the fall of level at the input Remember that the objective of the AGC is to assure that the signal reach the processing stages with a very stable level independent from the console s level The time that takes the AGC in compensating the gain reduction is called recovery time SOLIDYNE 462dsp broadcast digital processor e In order to process voices use slow recovery time so that the AGC can effectively c
33. der is the recovery time This is the time that takes a band in recovering its previous gain This is appraised at first observing the indicators The slower it is the recovery the processing sound soft and the music sounds natural However when they are fast an increase of the loudness takes place but the sound can becomes more rough SOLIDYNE 462dsp broadcast digital processor y AES In indicates if the unit is using the digital input It activates just at the moment at which the digital data enter digital input analog input y MPX Out indicates that the processor is using the internal FM stereo coder y Finally the screen shows the name and number of the current program You can explore the programs list turning the JOG but a program is not active until you load it pressing briefly the wheel A program is a set of adjustments stored in an internal memory You access to the MAIN MENU by pressing and holding the JOG wheel From here you can access to all functions and features of the processor Page 7 THIS PAGE HAS BEEN LEFT INTENSIONALL Y EMPTY Page 8 broadcast digital processor SOLIDYNE 462dsp Advanced installation Chapter 2 RDS DATA o ST g o AN al 1 y MPX OUT OUTPUT INPUT F IAL II FARBEN he S se Emo 4 to Lo de RS 232 2 1 Power supply e The AC voltage variation must stay small
34. der the final amplitude used in the point b Under these conditions the HOLD indication must be always on screen Realizar el barrido de respuesta frecuencia con una amplitud de 25dB por debajo de la amplitud final utilizada en el punto b Bajo estas circunstancias la leyenda HOLD deber permanecer siempre encendida Whereas no of the 4 bands must enter compression does matter the input frequency of the oscillator e At the audio output of the processor you must verify a response from 20 to 15 000 Hz with a variation of 0 7 dB f Repeat for the other channel 7 1 4 S N Input Audio generator at 1KHz on both input channels adjust the AGC so it compress 15db Output Connect a dB meter on left audio output XLR Procedure a Select the program N 26 b Take this output level as reference of maximum output level Page 33 c Quit the oscillator and measure the residual noise on the output d You must obtain as least a S N of 90 dB at the audio output e Repeat for the other channel 7 1 5 STEREO CROSTALK Input Audio generator at 1KHz on left input channels adjust the AGC so it compress 15db Output Connect a dB meter on right audio output XLR Procedure a Select the program N 26 b Take the output level of the left channel as reference of maximum level at the audio output c At the right output you must obtain a crosstalk bigger that 72dB difference between the level m
35. e dynamics of the bass stays using fast recovery times for the low band LF The high frequencies are not emphasized The objective was to prioritize the fidelity clearness and definition of the instruments over the brightness effect By such reason the recovery time of the high band HI is relatively slow Consider that the listener always can emphasize the trebles in his tuner by equalization This program also is very appropriate for TANGO orchestras although generally the tango tolerates a little more processing AGC OUT 7 dB and can require adjustments in the times of the bands of M1 and M2 by the stylistic differences in the use of the vocal intervention respect to the Jazz SOLIDYNE 462dsp broadcast digital processor 01 JAZZ IMPACT It s similar to the previous one but a little more strong slower attack times and faster recovery times JAZZ IMPACT apply a little increasing to the BASS CLIP threshold to reinforce the bass punch This processing works very well with Jazz POP country and blues folklore and tango 02 MELODIC Here was prioritized the human voice over the musical support To respect the color and shades of the soloists was the central objective when creating this program As reference was used material of diverse soloists of ballads boleros and melodic music Although this adjustment is centered in the voice is not equivalent to adjustment VOICE IMPACT since the
36. e form Soon you can copy the program chosen to a user memory and modify the adjustments to customize the sound When finalizing the adjustment assigns a password to the equipment to maintain the configuration unalterable Only the engineer who has the password can alter the sound of the radio Page 26 SOLIDYNE 462dsp broadcast digital processor 2 2 Solidyne 462dsp psycho acoustic digital processor 2 2 1 Blocks diagram Balanced Imput PHASE ASSIMETRY CANCELLER 24bits 192 KHz AD DIGITAL INPUT LINEAR EXPANDER MULTIBAND COMPRESSORS CROSSOVER NETWORK LINEAR 50 or 75 us PRE ENPHASIS 24 dB octave RESAMPLER UP TO 150 AM POSTIVE MODULATION AM only Y 4 BANDS IM FAST DENSITY CANCELLED LIMITER EQ CLIPPER 15 Khz LOW PASS DIGITAL FILTER R DIGITAL OUT Active balancer D A DE EMPHASIS CONVERTER DIGITAL SUPER MODULATION STEREO MPX CODER PROCESS SUPER MODULATION LEVEL CONTROL 2 2 24 BITS O 192 KHZ A D CONVERTER This module converts the analogical audio signal to digital audio with 24 bits of resolution with a sample rate of 192 KHz Digital Input Resampler AES 3 input supports resolutions of 16 24 bits and Fs from 32 up to 208 KHz An stage called resampler converts the digital input signal to 24 bits 96 KHz the resolution that the processor uses internally From here and until the signal returns
37. e signal in Auto Search mode After losing AES 3 or in absence AES signal or absence of audio in this digital signal the equipment switches automatically to the analogical mode The reestablishment to the digital mode happens in immediately in case signal AES 3 is had completely lost Since when recognizing a valued digital carrier the processor quickly returns to use the digital audio like source of incoming signal In case the digital signal exists but the same one contains silence the processor operates as follows At intervals of 5 minutes the processor interrupts briefly 1 sec the audio on the left channel connecting in its place the digital signal of the left channel verifying soon if the digital signal were reestablished If it continues in absolute silence then it reestablishes the analogical signal This process is repeated time and time again until as returns signal AES 3 When the digital audio reappears the processor returns to digital mode While the digital signal remains absent the audio on the left channel is briefly muted at intervals of 5 SOLIDYNE 462dsp broadcast digital processor minutes to alarm to the engineers of the radio and to the operators that the processor is working with the analogical backup inputs This has been intentionally designing in this way since otherwise an accurate confirmation does not exist on problems in the signal AES 3 A INPUT LEVEL Define the nominal level of the ana
38. e study of this subject is recommended to visit our WEB www solidynepro com In the DEMO section there are a Power Point presentation called Audio Processors It has a complete Technical Appendix that it analyzes how the audio processing increases the coverage area of the FM stereo transmission Also we recommended to read in our WEB the article Theory of the multiband processing 2 1 A brief history From mid of the 1930 decade when appears the first compressors and expanders units to the present time all chains of audio for broadcasting incorporate devices whose function is to alter the dynamic range of the sound The advance of the technology improves these devices during the 705 The compressors expanders and audio limiters were gaining in efficiency and complexity In the beginning its main parameters attack and recovery times thresholds etc were fixed by design or by the operator through the device s controls In the 70s these functions begin to be automatic based on the characteristics of the audio signal but having at the same time a control on their action to be able to customize the sound When five or more devices are grouped in same equipment they begin to be denominated AUDIO PROCESSORS Since 1970 Solidyne introduces important advances in this field like the invention of a control technique based on FET s with guided gate see publication in Rev Tel Electr nica September 70 They f
39. e the AGC would compensate the input level continuously increasing the background noise in the pauses due to the signal absence the AGC would increase its possible gain to the maximum The Gated AGC solves this disadvantage Strictly speaking AGC value is not congealed but that slips slowly towards O dB to avoid that it is hooked if the signal remains with low level slope 0 75 dB each 13 seconds 4 5 minutes from 15 dB On the other hand you can adjust the HOLD threshold to conserve part of the dynamic range of the music That is to say if a forte passage is followed by a subtle appearance of an instrument the AGC will hold its gain level giving rise to the contrast of loudness When the piano passage reaches the HOLD level the AGC unhold and begins to increase their gain according to the recovery time 4 4 2 5 Expander threshold Change the expander threshold from 50 dB to 80 dB in steps of 1 dB This level is referred to OVU input overload level The threshold is the point from which the expander begins to reduce its gain as signal level SOLIDYNE 462dsp broadcast digital processor is reduced The object of the expander is to improve the signal noise relation on the air This is because the multiband compression although increases the loudness reduces relation S R This effect would be annoying but for the action of the expander 4 4 3 MULTIBAND COMPRESSOR The object of the multiband compression is to
40. easured at the point b and the reached in the point d Repeat for the other channel 7 1 6 DISTORTION Input Audio generator at 1KHz on both input channels adjust the AGC so it compress 15db Output Connect a dB meter on right audio output XLR Procedure a Select the program N 28 b Under this conditions the audio output must be 2dBm 6 dB below the nominal level of 4 dBm By the other hand no of the 4 bands must enter compression c Proceed to measure the total harmonic distortion THD It must be around 0 01 d Repeat for the other channel Page 34 SOLIDYNE 462dsp broadcast digital processor 7 3 SC100 STEREO CODER Fine calibration protocol Normally the stereo coder don t need calibration because it s a full stable after many years design based on digital oversampling 16x technology If you wish to make a control or fine tuning please follow the following steps PLEASE IF YOU DON T HAVE A GOOD KNOWLEDGE OF THE MATRIX STEREO THEORY OR DON T HAVE THE APPROPRIATE MEASUREMENT SET DO NOT INTEND TO CALIBRATE THE STEREO CODER 7 2 1 TEST POINTS DIAGRAM SOLIDYNE SC 100a 3 TO TP 1 a i i GND MPX components side 7 2 2 ADJUST PILOT LEVEL a Connect to ground the test point TP1 R246 in order to eliminate the 19 KHz pilot tone Use a good DC 20 Mhz calibrated oscilloscope at the MPX output connector Using the displ
41. er to 10 Otherwise uses an UPS N Always CHECK the correct position of the AN VOLTAGE SELECTOR 200 240 V o 100 130 V according to the country AC wires do not have to be mixed with audio wires especially with analogical ones Remember that all audio installation must have a trustworthy grounding We recommend accomplishing with the effective norms Article 810 of the National Electricity Code NEC ANSI NFPA NS 70 1984 in USA IRAM 2379 and 2281 3 in Argentina This norm provides information and guidelines for a consistent grounding 2 2 On mounting e 462dsp can be mounted in a standard rack of 19 or can be used on a table Rubber tops are provided with the unit Do not place the unit on unstable surface or shelf the apparatus could fall causing damages to someone and to be damaged the unit e The ambient temperature must stay between 5 C and 40 C Avoid direct solar ray incidence on the processor or proximity of heat sources e The openings and grooves allow the circulation of air inside the unit These openings do not have to be blocked nor covered not to obstruct the refrigeration of the internal components e 462dsp has internal protection against RF fields which allows locate it next to transmitters SOLIDYNE 462dsp broadcast digital processor ANALOG I O AM or FM Avoid strong electromagnetic fields power transformers big motors etc 2 3 Analogical audio connections
42. erefore is desirable to increase the level of the mids highs frequencies But this cannot be obtained by simple equalizing since the sound balance would be destroyed The compression in separated bands allows to increase between 6 and 12 dB the energy for high frequencies without altering the tone balance In fact the frequency response continues being flat 3 Processing completely eliminate the flat sound sensation perceived when a sonorous material is compressed by means of fast compressors This is obtained additionally to the division in bands using attack times appreciably elevated This allows that very short peaks of the audio signal arrive freely to the following stage peak limiter which eliminates them but maintaining the Page 29 psychoacoustic sensation of power associated with the audio peaks This is related to the Burst Masking effect recently discovered Ref 8 2 2 6 DENSITY ECUALIZER This technology operates in 5 bands modifying the density of energy instead the level of each band Is formed by complementary filters of 24 dB octave carefully designed to obtain a response variation smaller than 0 2 dB This built in equalizer offers an enormous flexibility By example in the case of FM transmission is well known that the use of EQ at the console output has an adverse effect in the sound quality since the more a frequency band is emphasized grater is the action of the audio compressor prev
43. fic to arrive more force at the radio receivers from car when they are in the centric zone For other schedules smoother adjustments can be used and finally last in the night to set a very smooth programming to accompany music The frequent change of the processing ways tends to fight the auditory fatigue that happens when the radio sounds always equal throughout the day Note This feature requires a PC connected to the 462 s running 462dsp VirtualRack e Manage the 462dsp processing programs from the Solidyne Audicom7 on air automation software You can change the programs according to the musical style The software runs on Windows 2000 XP For more details about this software please refer to the on line help contained into the CDROM 5 2 Set up and connections Interconnection is made using a standard cable RS 232 with DB 9 female connectors in an end and male in the other The computer must have an available serial port SOLIDYNE 462dsp broadcast digital processor VirtualRack software automatically recognize to the 462dsp by exploring all RS 232 ports An USB to RS 232 adaptor of good quality can be used It is obtained in any computer s store Please refers to the on line help for details about the software Page 23 THIS PAGE HAS BEEN LEFT INTENSIONALL Y EMPTY Page 24 SOLIDYNE 462dsp broadcast digital processor Cap tulo 6 Audio processing for broadcasting NOTE in order to complement th
44. hannel separation better than 75 dB It s based on the oversampling concept that divides the audio signal in 16 samples that are processed separately at 38 x 16 608 KHz Due to this elevated sampling rate the anti alias filters works over 500 KHz eliminating the phase rotation effect that take place at 53 KHz which no allow to achieve a good channel separation With this new solution and the use of advanced technology in each part of the circuit residual components of distortion below 90 dB are obtained It is described separately in this manual the way to do measurements and reception tests of the stereo coder see Chapter 7 2 2 10 MPX PROCESSING The studies about the modulation on an FM transmitter indicate that when the transmitter is modulated by stereo MPX signal appears a new effect not present on the original audio signal This effect called MPX Interleaving also known as peak correlation determines that the modulation peak in MPX does not coincide with the modulation peak of the stereo signal considered in independent form Solidyne processors uses a MPX Processing technology named Super Modulation This processing consists on a system that controls the peaks operating at 608 Khz eliminating the peaks in MPX base band signal and filtering them so that there are not left residual components in the audio band SOLIDYNE 462dsp broadcast digital processor REFERENCES 1 S S Stevens The measureme
45. ia to the ear to avoid perceiving the distortions due to deficiencies in the quality of the electronic circuits of the processors Considering that to obtain an excellent processing is necessary at the moment to use between 7 and 10 stages of processors the distortion of each stage must be smaller than 0 01 Greater distortion values will lead inexorably to a degradation of the sound quality You must remember that has been demonstrated Journal of AES Vol 29 4 p 243 that is possible to measure distortions of 0 05 through a common loudspeaker distortion bigger than 3 This demonstrates that one distortion do not mask another one A practical rule is then ALL DISTORTION INTRODUCED IN THE AUDIO CHAIN OF THE TRANSMITTER THAT EXCEEDS 0 05 COULD BE LISTENED BY THE AUDIENCE EVEN THROUGH RECEIVERS THAT HAVE VALUES OF DISTORSION 50 TIMES GREATER This of course is not a novelty for the conscious audio engineers around the World Therefore the line of SOLIDYNE processors has distortion values smaller than 0 02 Friendly interface 462dsp has many of its automatically fit functions under control of the program of audio But there are essential controls for ing personalize ng personalize the sound of its radius that are fit by the user The unit has several programs fit in laboratory for an optimal performance with different types from sonorous material These programs allow you to be on the air in immediat
46. ich is described briefly at next as introduction to the 462dsp graphical environment E 05 POP Pee Tees wil mex a LR AG 1234 WL a cote Ae anne Lleno Page 6 program and state of inputs and outputs also appears on this screen From left to right you find y The input VU meters L amp R Below the vu meters an overload OVL warning can appear which turns on 8dB before the digital clipping level 18dBm This warning turns off last 5 seconds if the clipping condition disappears y The following bar shows the action of AGC Automatic Gain Control that fits the input gain so that the signal arrives at the processing stages with constant level In others words if the signal from the console arrives with low level or very high the processor automatically compensate its input gain so that the output level is uniform This is a gated AGC If the input signal falls abruptly broadcast digital processor SOLIDYNE 462dsp the AGC holds its current value to avoid an undesirable effect known as breathing that appears when the signal is very low and the AGC compensates their gain excessively increasing the background noise in the voice intervals In normal operation this indicator will have to work at middle scale 15 dB y The following indicators show the action of the multiband compressor There are four compression bands called loudness bands LF M1 M2 HF These indicato
47. iminishes Faster recovery times increase the loudness of the highs and the brightness of the sound but it can be a little rough sound for some musical styles Note The attack like the recovery has a scale for band LF and M1 and another one for bands M2 and HF Band SF copies the scale from HF Page 22 4 4 4 DENSITY EQUALIZER This technique eliminates the problem of the conventional console s equalizers whose action soon is canceled by the multiband processor since it compresses what the equalizer reinforces The technique of Density EQ operates in combination with the multiband compressor Therefore its adjustments are interactive Density EQ works creating four floating thresholds for the average sonorous energy in four frequency bands 80 Hertz 1 KHz 6 KHz and 12 KHz This equalization allows to obtain still in conditions of high loudness a contour of equalization based on the energy of bands instead of differences of relative gain between the bands like in a conventional EQ CEPA A 50 6571 5 Tu 43 95 25 60 35 BE en 50 15 3 15 E en 15 10 5 To change a value select a band and touch briefly the JOG note that the arrow becomes a pencil Turn the JOG to move the slider The dotted area is only for laboratory testing It is not a safe operating zone for audio processing Bass Clipper Punch This control changes the threshold of a low band limiter The cha
48. in American percussion instruments By such reason the attack of the mid band M2 was freed and in smaller proportion the high band approximately 16 mS and 12 mS respectively This increases the presence of that bands in which great part of the spectral components is concentrated that contribute to definition and brightness to the instruments before mentioned The effect reinforces with a fastest recovery in the high band 28 mS The attack for the low band is also something slow 65 mS whereas its recovery is of the order of 1 2 second The objective is to obtain basses with great height but without losing the attack of vital importance in these rhythms since many times the bass is who takes the cadence of the song This adjustment can be considered a moderate processing since the AGC output AGC is fit around 8 dB This adjustment is very appropriate also for Son Salsa and its derivates For these styles the processing can be increased increasing the output level of the AGC until around 12 dB 07 ROCK IMPACT It s the ROCK program but with a little more processing 08 POP This is another moderate preset Designed for POP music which include very many styles this adjustment looks for obtaining very good loudness and a flat curve of EQ with good dynamics The AGC level is around 7 dB The density EQ reaches its maximum value in the band M1 with 7 8 dB As was already said the
49. increase the energy in the entire audible spectrum The theoretical foundations of this technique are explained in Chapter 6 of the 462dsp user s manual Next a brief review of multiband compression offers and is detailed soon how different processing adjustments affect to music and the word Remember a compressor is basically an amplifier whose gain changes from a certain level of signal This change of gain denominates compression ratio For example a compressor with a 2 1 ratio will produce an increase of 1dB at on the output when an increase of 2dB takes place in the input In this case the increase of signal on the output was half with respect to the increase on the input The level from which the compressor begins to be not linear calls compression threshold When the signal surpasses the threshold the compressor begins to work On the other hand when the signal surpasses the threshold the compressor takes a time in reacting to modify its gain This time is denominated attack time and during the attack the relation input output pass to be linear to work according to the compression ratio When the input signal reduces the compressor takes recovering its original gain that is to say during a short time it continues compressing This time is called recovery time In 462dsp the compression thresholds are the same for all the bands to not alter the sonorous balance The compression degree simu
50. ious to the transmitter for that band Equalize a band implies to unbalance the entire audio spectrum It doesn t happen with DENSITY EQ since its action is coordinated with the following stages The boosting of a frequency band is translated then in a correlative modification of the multiband compressor threshold to carry out the new equalization In this form its action extends to the range of sounds of very high intensity where the conventional EQ s are inefficient due the excessive compression 2 2 7 IM CANCELLED CLIPPER The analogic era One of the techniques most well known and used to increase the energy of an audio signal is the use of an audio clipper With its evolution the analogical processors was optimizing this technique to reduce the udesired effects caused by the clipping The problem appears because when an audio signal is clipped it generates a high number of harmonic components and intermodulation IM The psychoacoustic studies have demonstrated a high tolerance of the ear towards the harmonic components increased by the aural masking that the multiband processor allows to obtain In fact all the musical instruments as much as the synthesized ones have a high amount of harmonics superposed to their fundamental notes Therefore adding harmonics artificially increases the wealth of the musical timbre Opposed is the effect that the distortion by IM produces This type of distortion DOES NOT EXIST
51. isma ganancia que ten a antes de caer la se al Esta caracter stica permite un funcionamiento m s natural del procesador puesto que evita que en las pausas entre los di logos por ejemplo se note la respiraci n del AGC incremento en el ruido o soplido de fondo O que al terminar un tema musical se escuche un aumento del ruido de fondo antes de comenzar el tema musical siguiente etc 2 2 6 MULTIBAND COMPRESSOR The purpose of the multiband compressors is to increase the perceived loudness sensation The human voice and music will sound more solid with better dynamic balance Still more the increase of the average energy of the audio signal is very considerable increasing the coverage area of the radio for A M and FM transmissions for more info please visit www solidynepro com Multiband technology bases on the studies of Stevens ref 1 2 3 about the loudness of each band frequency and the studies of Zwicker ref 4 About its relation with the Critics Bands of the human ear The integration time of the ear to reach the maximum loudness is of the order of 200 milliseconds ref 5 This time must carefully be incorporated to the controls of the loudness compressors to obtain the desired effect The ear will perceive a greater loudness when the band compressors increase the relative loudness level SOLIDYNE 462dsp broadcast digital processor The processor Solidyne 462dsp has digital frequency splitters with Butterwo
52. ived like a great dynamic range whereas the power sensation and even the coverage area of the radio transmitter is related to the AVERAGE ENERGY which depends of the compression of the energy level You can see that they are two concepts different With audio processors of conventional design the expander and the compression were antagonistic concepts This does not happen in the field of the psychoacoustics processors SOLIDYNE 462dsp broadcast digital processor 2 2 5 GATED AGC This stage constitutes a digital compressor AGC type Automatic Gain Control with its constants slow based on the program signal This adjustment is made having in mind the psychoacoustics criteria before explained This is very important since the AGC is a wide band compressor the ear tends to note its action due to the modulation that bass frequencies produce in the highs In order to avoid it the AGC time constants are carefully controlled Still more we cannot speak of attack or recovery times in strict form but a curve of control since the way of the attack or recovery ramp is controlled according to these criteria Otra caracteristica importante de este compresor es que su recuperaci n es GATILLADA Es decir que solamente acciona en presencia de se al de programa Cuando el nivel de programa cae por debajo de cierto umbral con respecto al nivel de salida del AGC la recuperaci n es cancelada y el compresor permanece exactamente con la m
53. l 10x undistorted span Proceed a Change the SC 100 PHASE jumper JF1 from the Normal N position to calibrate C position b Input a sine wave generator at 1 KHz 4 dBm at Left Channel of the audio processor Adjust the level of wave generator to get 4 Vpp MPX output c Connect the oscilloscope to the MPX output in mode DC Use the sine wave output of audio generator to synchronize the oscilloscope sweep Adjust the sweep to 5 uS Div Modify with trigger level the center of the wave in order to have it centered at screen Adjust vertical sensitivity to 50 mV Div You must get a signal like FIG 2 If not you must do a slight change in the frequency knob of the audio generator in order to avoid integral multiplication factors that do not allow you to appreciate the correct image Calibrate the P3 Phase Control to get zero phase error The phase error is indicated by the tilt of the imaginary line between H1 H2 points When this line is full horizontal the phase is correct FIG 2 Pilot Phase 10X Page 35 e Change the phase calibration jumper to NORMAL mode N position 7 2 4 CHANNEL SEPARATION Due to the high channel separation of the Solidyne SC 100 the only way to recalibrate to original specifications is to use as reference a good measurement set like the BELAR USA model FMS 2 If you do not have an excellent measurement set please do not intend this calibration Anyw
54. lied compression is something soft that is to say fast attack times and slow recovery times In this way the signal is more compressed It is denominated soft because when a compressor acts for example M1 on a guitar the compressor reacts immediately to have a fast attack and maintains with its gain reduction slow recovery containing the successive attacks of the guitar that are not affected by the attack because the compressor still did not recover Obviously the dynamic range perceived in this type of adjustment is lost almost completely basically due to the compression The combination of a hard compression with high gains will cause a heavy processed sound which will sound rough on the air with certain type of music SOLIDYNE 462dsp broadcast digital processor 14 VOICE IMPACT This adjustment specially is designed for locution When 462dsp is connected to the console using MICstart opening the microphones 462dsp changes its program to process the voices with a special adjustment The AGC must recover fast to compensate for example a telephone communication that arrives with low level The hold threshold must be relatively low around 17 dB to avoid that the AGC is hooked and in this way to obtain that it reacts quickly before any difference of level between different voices Remember that the objective is that the voices always sound on the air with the same level The attack of the AGC also must be f
55. logical input signal So that the AGC automatic gain control operates correctly is very important to fit this level correctly This value must agree with the nominal output level of your console in the case of Solidyne consoles this level is 4 dBm NOTE If you unknown the output level of your console put the console s level at 0 VU peak and reads the level in the 462dsp s input VU meters With the adequate input level the AGC works around 10 to 15 dB of gain reduction This can be seen in AGC indicator who will have to indicate 15 dB with strong program signal lowering to 8 dB or less when the signal reduces If the program signal level abruptly falls the indication HOLD appears Overload warning OVL appears in the main screen when the input signal reaches 10 dBm that is to say 8 dB before the digital clipping threshold placed at 18 dBm The indication disappears last 5 sec if the clipping disappears The digital input fulfills recommendation AES K12 applied to broadcasting which takes as reference for 0 VU a digital input level of 12 dBFS This implies 12 dB of headroom The user cannot modify the input level when digital input is used 3 2 2 OUTPUT SETUP OUT LEVEL ddEu NnClose DIG OUT FRE EMFH S6KHe A T5uz O 45KH2 O 5005 OUT LEVEL It refers to the analogical output Level is fixed at 4dBm DIG OUT Define the sample rate of the AES 3 output It can be 96 KH
56. ltaneously adjusts for all bands changing the level with which the signal enters to the compressors AGC Output As greater is the level greater is the compression You can set the attack and recovery times for each band Have in mind that the settings for the compressors and density EQ s varies according to the type of program material reason why there isn t a unique adjustment 100 optimal for all musical styles A great feature allows remote control from the automation PC using software Solidyne Audicom7 to change the processing program according to the music style Remember that VirtualRack 5 also allows defining program changes according to a scheduling Next a screenshot of the multiband compressor stage and soon its description 10ms Sms LF Ome 2 05 E5lmS 5 m 4 03 A ACA Close ATTE DT RELERSE Sims 055 40 1 Op 15 ms a 1 5 5 0 o Foam 0 0 21 4 4 3 1 Attack times It s the time that takes the compressor in acting once the signal overpasses the threshold Slows attack times gives more impact to the sound but greater will be the action of the limiters This is because the attack of the sound passes through compressors and arrives at the limiters with high level The limiters contain the peaks by clipping a technique much more lasts that the compression With short attack times hard clipping is avoided but very short times can produce a sound too fl
57. minimum value the THD meter c Use the monitor output of the THD measurement set to analyze the distortion products in order to separate 38 KHz residual and noise from the true distortion components Use a Tektronix 5L4 N analyzer or TiePie FFT HS3 probe or SoundTech Lab software etc Identify the harmonics of 1 KHz and calculate Distorsi n HY H1 Level of fundamental tone Hn Level of harmonics reduced by the gain set of the THD meter Verify that the distortion level is lower than 0 003 at 1 KHz d xw SOLIDYNE 462dsp broadcast digital processor Chapter 8 Technical specifications Analog Input Digital nput Analog Output Digital Output MPX Output Processing Technology MPX Post Processing Frequency Response Harmonic Distortion THD Noise Stereo Separation Subsonic Filter Asymmetry Canceling Linear Expander Gated Wide Band AGC Multiband Compressors Compressors Attack Release Time IM Canceled Clipper Fast Clipper Density Equalizer Low pass filter Storage of Preset Settings RS 232 PC control Super Modulation RS 232 PC control AM FM compatible Processing Bands and stages LCD Display RDS Encoder Power Dimensions SOLIDYNE 462dsp broadcast digital processor 600 10 K balanced XLR 50 dB CM Rejection 20 15 Khz Input level selected by software in 1 dB steps Sigma Delta converters 24 bits 192 Khz Optional AES 3 digital b
58. n advices and tips of extreme importance broadcast digital processor SOLIDYNE 462dsp Chapter 1 Quick installation guide 1 1 Basic connection and settings Power supply Outputs Power on CONECTIONS Before plug in check the position of the AC VOLTAGE selector on the rear panel 200 240 V 50 60Hz or 100 130 V accords to correspond Analogical audio inputs are balanced using XLR female connectors Connect the PROGRAM OUTPUTS of your console to these inputs Take care of not invert the phase of the channels Optionally the 462dsp has digital AES 3 AES EBU input for digital consoles or links This input supports 16 24 bits and sample rates from 30 up to 96 KH When the digital input is used we recommend connecting the analogical inputs too 462dsp will switch automatically to these inputs in case of failure on the AES 3 signal 1 Connects the 462 s MPX output BNC to your transmitter exciter The unit has an ON OFF switch on the rear panel The main screen Hill show a welcome Splash on start up and then will load the last used program SOLIDYNE 462dsp broadcast digital processor Controls mu EL CONFIRM MECANCEL Input Programs e JECONFIRM_ 1 0114427 CLASSIC SETTINGS All settings values are entered using a JOG Wheel Turn the JOG to select options and to change values Pressing briefly the JOG confirms an option
59. nd to use some of the 15 default presets Only sound technicians with great patience will have to try to make their own adjustments lts patience will be compensated surely by a customized sound different from the sound of other radio stations Please read carefully the description of each adjustments made by Solidyne Take it the time to listen to each program and how each control affects to the sound on the air Once you knows clearly so that of each adjustment comes to make your customized adjustment This way will be easy for you to obtain that sound that you have in mind e Of no way is recommendable to change values completely without information without knowing how will affect each change to the sound of the radio Finally an encouraging commentary these adjustments are zero risk because you always will be able to return from the default program that never change SOLIDYNE 462dsp broadcast digital processor Page 19 4 4 PROGRAM USTMENTS The screen Edit Program shows the blocks diagram of the processor showing the main stages involved in the audio processing The operation is the same one that in other screens Turn the JOG to select a stage and touch briefly to enter GEO El a WIJF ol Eres AN LISTENING ON THE EDITION Next we will see the different forms to create or to modify the sound of a program Each change that we make will listen on the
60. nge of this threshold allows to brings punch to the music s below 80 Hz Increasing this threshold you increases the bass peaks but not the general bass loudness in a noticeable way You must use a monitoring system with good low response to hear this adjustment Values over 4dB must be carefully tested according to the music that your radio station plays so it can produce audible distortion with some music s styles All default presets uses this control at the minimum 6dB except Melodic Hi Boost POP Night FM and Rock AN REMEMBER e Changes occurs in real time that is to say as you modify the value the change will be listened on the air SOLIDYNE 462dsp broadcast digital processor Chapter 5 Remote Control 462dsp can be controlled from a PC by means of RS 232 connection The control software VirtualRack 462dsp offers numerous features e To change the current program to anyone of the 30 presets from the PC using a drop down menu The change take place in real time e Create and edit the programs with an advanced graphical interface e Save the factory presets and user programs to the HD as backup or to transfer them to others 562 s units e To automate changes of processing according to a scheduling to use different processing programs from different hours from the day You can increase the loudness of your radio in the rush hours of car traf
61. nt of loudness ASA Journal Vol 27 pg 815 2 S S Stevens The direct estimations of sensory magnitudes loudness American J Psychol 69 1 25 1956 3 S S Stevens Concerning the form of the loudness function ASA Journal Vol 29 pg 603 606 1957 4 E Zwicker Flottrop Stevens critical bandwidth in loudness sumation ASA Journal Vol 29 pg 548 557 1957 5 Stanley Gelfand Hearing pg 392 Edited by M Dekker N York 1990 6 Oscar Bonello NEW IMPROVEMENTS IN AUDIO SIGNAL PROCESSING Journal of the Audio Engineering Society Vol 24 5 USA 1976 7 Oscar Bonello PC CONTROLLED PSYCHOACOUSTIC AUDIO PROCESSOR 94th Audio Convention Berlin March 1993 8 Oscar Bonello Burst Masking Enmascaramiento por Rafaga Anales del Il Congreso Iberoamericano de Ac stica Madrid octubre 2000 Page 31 Page 32 SOLIDYNE 462dsp broadcast digital processor Chapter 7 Measurrements 7 1 MEASURREMENT PROTOCOL Next instructions offer to make diverse measurements in case that it is required to state the engineering specifications of the equipment 7 1 1 Checking the INPUT LEVELS Input Audio generator at 1 KHZ on both input channels the amplitude is varied throughout the test Output Oscilloscope on XLR audio output Procedure a Select the program N 28 b Adjust the input level of the processor at 8dBm and check that for this input level both input VUmeters be exactly a
62. ollow diverse publications having particular international relevance the work published in June 76 at the Journal of the Audio Engineering Society New York U S A where a new concept was introduced that persist to the present time PHSICOACUSTIC PROCESSING This new technique is the base for all the modern audio processors for broadcasting use The necessity to process the phase to make symmetrical the human voice waveform is another one of the techniques that Solidyne has introduced internationally see mentioned article AES Today our ideas are used by Orban Omnia Aphex etc The concept of psychoacoustic processing is simple in essence although of complex accomplishment It consists of analyzing the way SOLIDYNE 462dsp broadcast digital processor in which the sound is perceived by our ear considering diverse investigations and developed acoustic models The brain uses to process audio data the information that arrives through 30 000 nervous fibers originating at the Basilar membrane Then it will be possible to be computed the auditory reactions and to be governed all the aspects of the audio processing This way the electronic system works transforming the original signal into another one of greater energy and greater quality of sound Then it will be possible to reduce the dynamic range of the audio signals to eliminate the peaks and even to clip them partially to increase its energy If this were made di
63. ore freedom to make the adjustments In this case was chosen to emphasize a little the lows and the highs presence This last one is obtained making fast 60 mS the recovery of the high band whereas the attack of this band adjusts a little slow 20 mS This causes that enters in action the fifth band of high frequency post processing HF The weight in the basses obtained with a fast attack and a slow recovery in the low band and increasing the gain of this band in the density EQ Respect to the AGC the output level is located about 9 dB with slow attack and recovery times This adjustment also is useful for new age music Although these styles are stylistically different share the use of synthetic atmospheres and moderate to slow tempo 11 REGGAE Is a variation of Chill Out preset with higher Bass Clipper threshold 4 dB 12 BOSSA NOVA This is a moderate preset Attack times are fast and recovery times are moderate 13 MAX LOUDNESS This it is the more radical adjustment As the name of the program suggests the primary target was to obtain a great loudness on the air and improved reach of the FM leaving in background the clarity of the sound and the spectral balance The output level of the AGC is located in 15 dB whereas the density EQ reaches 6 5 dB in the band M1 the highest adjustment between the 15 default programs Since the gains of the AGC and density EQ are high the app
64. ore the list and touch briefly to put a preset on the air Note that while you explore the programs over the program name appears the navigation instructions e While these instructions are on screen you are in the mode exploring programs Selecting a program this legend disappears e Touch and hold the JOG to cancel the exploration The name of the current on air program returns on screen THE CHANGE WILL TAKE EFFECT ON THE AIR JUST WHEN YOU LOAD IT BRIEF TOUCHING THE JOG 4 2 DEFAULT PROGRAMS 462dsp has 15 programs created by the Solidyne engineers Next each preset is explained These adjustments are the base for the creation of new programs 00 JAZZ CLASSIC orchestral This is a soft program The objective was respect the original equalization and balance of the orchestra maintaining its dynamic expression by all means within the limits of the FM transmission For this the AGC uses slow attack and recovery times and its output level is around 4 dB for not to produce excessive compression Remember that an excessive compression will cause a spectral imbalance unacceptable for Jazz music and orchestras The times for the bands M1 and M2 require special attention since there is much participation of soloist s instruments in this music The recovery times must be similarities otherwise timbre modulations will take place mainly in wind joints This adjustment reinforces the lows subtly Th
65. orrect differences in the program signal Let us analyze an example the telephone line arrives with low level While the speaker in studies speaks the AGC works at certain level when the caller speaks the telephone presents less volume on the air and the AGC must act fast to correct this situation increasing its gain When the speaker returns the AGC will reduce their gain again And it will have to act with very little delay The hold threshold will have to be low to avoid that the AGC is hooked freezing their value during the telephone communication of previous example The AGC attack and recovery times must be carefully defined so that its action is not in evidence If the attack time is excessively slow the action of the AGC could notice the level reduction can notice If the recovery time is very slow and the attack time is very short when somebody shouts a cough an outburst of laughter the AGC reduces its level abruptly and takes soon in recovering its level Then the effect will be similar to somebody lowered the volume of the radio For music it agrees that the recovery time be slow If it s fast the dynamic of the music are completely lost 4 4 2 4 Hold This is a gated AGC For this reason when the input signal falls abruptly the AGC does not compensate its gain but that congeals their current value remaining in that state until the signal exceeds the hold threshold Otherwis
66. pe of input The operation on this screen follows the concept of the previous ones to select an option Input selection or Input level turn the JOG and touch briefly to confirm Now turn the JOG again to change the value of the chosen option Touch briefly to confirm Page 14 Selecting this option the following screen will appear EFE INPUT SELECTION A INPUT LEVEL O ANALOG 0 0 dEm dEm 0 Em 12 0 dEm O DIGITAL ONLY auto SEARCH INPUT SELECTION Analog Select this option when the processor is connected ONLY through the analogical input Digital only Choose this option when the unit is connected ONLY through AES 3 Also the analogical inputs can be connected as back up but they will be used only in case that the carrier of signal AES 3 interrupts In this case the equipment exchanges automatically to the analogical inputs being in that mode until the digital signal is reestablished Auto Search default It uses the AES 3 digital inputs in case of finding a source of digital signal Otherwise uses the analogical inputs In case of finding only silence or a total lost of digital AES 3 the unit switches to the analogical inputs This type of faults in signal AES 3 is characteristic when a digital data link falls As signal AES 3 is regenerated in the receiver the digital streaming follows present but without content of audio channels muted Reestablishing th
67. rectly obeying to purely electronic concepts of efficiency the quality would be degraded and the sound would be very poor If however the psycho acoustic concepts are applied and factors like the aural masking the pre and post pulse inhibitions the Hass effect the reflections at the ear pinna the aural models of Dr Karjalainen etc it will be possible to create a new generation of processors that allow to important increases of energy increasing at the same time the sensation of Perceived Sound Quality At the light of these discoveries the psychoacoustics processing was defined in these terms PHSYCO ACOUSTIC PROCESSING is the technique that allows to increase the range of AM stereo FM transmission by increasing the energy of the audio signal and also increasing the quality of sound perceived by the listener Nevertheless it is fundamental throughout this process to maintain very low the audio distortion produced by harmonic and IM components This happens because the psychoacoustic processing MODIFIES the waveform of the complex signal of audio but IT DOES NOT DISTORT IT Since the distortion concept in this context implies the existence of a sound that offends the ear sounding unnatural This is because the psychoacoustic processing obtains that the ear accepts like of better quality than the original one to certain modifications of Page 25 the waveform But it does not mean an anesthes
68. rs like the AGC show the containment of each band that is to say the compression gain reduction applied to the signal for that reason they grow downwards Band LF corresponds to bass notes of the audio below 160 Hertz M1 and M2 to mid tones and HF to the highs The LOUDNESS concept associates to the sensation of sonorous power perceived by the human ear With no need to exceed the maximum percentage of modulation fixed by the laws the processor can obtain that the radio sounds stronger The radio with better processing will be the one that better sounds in the dial As will be explained later another objective of the processing is to increase the energy in the entire audio spectrum to produce the maximum possible modulation in the RF carrier which is translated in greater radiated energy improving the transmission reach For this the processor applies a complex procedure of compression on each audio band producing greater sensation of loudness to the ear The size of each luminous bar indicates the compression degree at every moment Its effects obviously changes according to the different types of music and voice but in general can say that when a band indicator begins to light values up to 10 dB the action is smooth and is totally accepted by the human ear With values of 20 dB or greater will notice a greater sonorous force being a level of extreme processing Another important value to consi
69. rth filters of 24 dB octave that divides the program signal in five frequency bands lows low middle high middle highs and super highs The sub bands high middle and highs works in combination with the 5 band super highs processing the highest frequencies of the audio spectrum This 5 band is of great importance since take incidence over the peaks of the signal one of the most critical processes carried out by any audio processor The controlling of the dynamic range using band frequencies offers great advantages 1 To increase the total energy by the use of fast compressors for bass and ultra fast for treble If the bands were not divided the compressors with so fast recovery time would produce a disagreeable sound effect the percussion of low frequencies would modulate the high notes And the high notes of an instrument would as well modulate the low tones of a violoncello for example The increase of the energy increases the cover area that is to say the reach of a stereo FM station See demonstration in paper of O Bonello AES Journal New York March 2007 2 Allows to increase the perceived loudness This is because most of the modulation capacity of a transmitter or audio amplifier in general playing Pop music is generally used by low frequencies signals below 160 Hz Nevertheless this information contributes very little to the loudness sensation due to the reduced sensitivity of the ear for those frequencies Th
70. s by excessive excursion of the cone The sound that is obtained with the connected filter is pure and clean 2 2 4 LINEAR EXPANDER The expansion previous to the compression process is an excellent resource to increase the signal noise ratio of the original program This is advisable since the compression process when reducing the high level passages consequently increases the relative level of the passages of low level and therefore the noise This is a forced consequence of the compression process that has particular effect in the increasing of the ambient noise of the microphones In order to avoid that the Solidyne processors incorporate a linear expander previous to the compressor stage The expander works within a very wide range of signals below a threshold value That means it always expands within that range for any level of Page 28 signal The curve of transference based on the input level is a straight line from there the linear name While the signal stays below the threshold by each 10 dB that the input level reduces the expander will reduce for example 3 dB additional 1 3 1 ratio that is to say that the output will be reduced in 13 dB This happens for any input value below the threshold Then if the input is reduced in 30 dB the output will do it in 39 dB that is to say that the background noise has been reduced in 9 dB This way the expander compensates the increase of the background noise
71. s it to exceed 100 on peaks of frequent recurrence This indicates that in transitory peaks and no frequent 100 of modulation can be surpassed staying within the legal frame The 462dsp processor is designed to fulfill this FCC Norm being allowed to surpass 100 in no recurrent peaks slightly When fitting the modulation verifies the norms of its country When making the programs take in count if there is an UNIQUE program for the whole day In that case commitment solutions will be use to accept all types of voices and music that the Radio emits Using the remote control from PC diverse programs can be created This eliminates the commitments so each program will be the optimal for that type of music or voice In addition this automation eliminates the listener s ear fatigue associate with the radio stations that use rigid processors SOLIDYNE 462dsp broadcast digital processor Page 15 3 2 3 PROCESSOR SETUP AAA PROCESSING PGM 14 VOICE IMPACT i FROG MODES pPAsS Emo en CI MIC PROCESSING PGM MICstart input allows to change the processing program when the operator activates the microphones at the console applying a specific processing to obtain high impact voices nels This is a very useful feature since it s not possible to obtain an adjustment that sounds optimal for music and voice simultaneously for being two audio signals morphologically different The attack and recovery time
72. s of the AGC differ sensibly for both cases and must be carefully fit to avoid that its action is audible This option is disabled from factory program 30 Mic processing off In order to enable it select Mic processing PGM and choose a program created for voices for example 09 VOICE IMPACT The commutation controls from a connector in the rear panel detailed in the installation chapter see 2 5 Console MIC Start amp TIPS The programs for music and voice do not have to be radically different The gains of the density EQ and the AGC output must stay without greater variations The differences will be fundamentally in the attack and recovery times of the AGC and the multiband compressor It agrees to create the adjustment for voices starting from the adjustment chosen for music The attack and recovery times used for music usually are slower than those required for the voices mainly in the AGC Observe and compare the factory presets PASSWORD You can define a password to avoid the access of unauthorized personnel to the main menu to change the settings Once defined 462dsp will ask for the password whenever you try to accede to the main menu but you don t need the password to explore the program list and change the program on air Page 16 The password must have 3 characters Any combination of letters numbers and symbols can be used e To enter a password go to field
73. tep more in the field of digital clippers using a new system of 4 channels with 10 MHz of bandwidth that is equivalent to 32 bits with 20 Megasamples that obtains that absolutely clean and crystalline sound free of spurious and stridencies caused by aliasing For it we used a configuration like the FIG 4 in which we have two cut channels The channel of serious and average on the one hand does not cause intermodulation The channel of high frequencies main person in charge of the IM has a filter that eliminates all IM below 900 Hertz 1 KHz 900 Hz 15Khz Audio input with pre emphasis after compressors Clipper Ir 160 Hz 1KHz SOLIDYNE 462dsp broadcast digital processor 2 2 8 LOW PASS 15 KHz DIGITAL FILTER In order to be in agreement with the standards for FM stereo transmission a 15KHz low pass filter is at the input of the stereo coder which produces an attenuation gt 50 dB at 16 6 KHz to avoid interference with the RDS sub carrier and gt 60 at the pilot tone 19 KHz Is an digital elliptical filter of great stability This filter also guarantees that not exist spurious components at the RDS band of 57 KHz 2 2 9 DIGITAL STEREO CODER It uses digital technology to generate the MPX signal This technique created by Solidyne allows obtaining a coder with excellent features with distortion 10 times below the audibility threshold and c
74. to the analogical domain D A converter all process descript are made into the DSP s using complex algorithms AN REMEMBER e In case of failure in the digital signal the unit automatically changes to the analogical inputs SOLIDYNE 462dsp broadcast digital processor Internal computer with extemal PC amp control interface MPX OUT 2 2 3 PEAK SIMETRIZER It is known that by a particularity disposition of the vocal cords the sonorous emissions that these generate are asymmetric triangular pulses The three cavities that filter and shape these fomans to obtain the vocal sounds do not modify this intrinsic characteristic of the human voice All the spoken word and still sung is strongly asymmetric This creates an important reduction of the energy of the audio signal particularly when it pass through a compressor because the compressor sets its compression level for the greater peak does not concern its polarity In this way when a polarity is fit to the 100 the opposite polarity hardly surpasses 50 due to the asymmetry The fact that the music sounds louder than the human voice after pass through a compressor is a phenomenon well known This is because the musical sounds are symmetrical whereas the human voice is not In order to correct this problem WITHOUT INTRODUCING ANY ALTERATION AT THE SOUND QUALITY peak asymmetry canceller is used Page 27 This technique based in a disco
75. very d the Dr Leonard Kahn acquires international validity with the work of Oscar Bonello published at the Journal of AES Vol 24 5 in which it is described for the first time the theory of its operation The peak asymmetry canceller is in essence an all pass network a class of not minimum phase network That is a network whose transference function has zeros in the right semi plane This network has a full flat response to frequency only its phase response is function of the frequency This phase rotation which must compliment a very particular condition is responsible of the peak symmetry of the audio signals Those signals that by their nature are totally symmetrical like most of the musical instruments are not modified by this processor This processor by itself allows to increase between 3 and 5 dB the final power broadcast by your transmitter it is to say that it increases by a factor of TWO the average power transmitted Numerous tests have been made in different countries to verify in real conditions these results 2 2 3 SUBSONIC PHILTER Is a Chebyshev type high pass filter with low ripple Its cut off frequency of 20 Hz eliminates the signals of audio below that frequency These subsonic components do not contribute anything to music since they aren t listened by the ear Nevertheless they have a pernicious effect that produces a disagreeable sensation the saturation of the amplifiers and the loudspeaker
76. z or 48 KHz MPX Level Define the MPX output level It can change from 2V to 5V peak to peak You must set the value according to the value that the transmitter needs to reach the 100 of modulation 75 KHz deviation PRE EMPHASIS Allows to adjust the pre emphasis curve according to the regulations of your country LE Europe 50uS USA ASIA Latin American 75uS 3 2 2 1 Adjusting 100 of modulation in FM For this adjustment use a program material of high density with voice and music i e commercial spots Select the program 08 MaxLoudness it produce high output level Next change the MPX output level until obtaining 75 KHz of deviation measured with a Monitor of Modulation like the Solidyne VA16 or with the modulator meter of the transmitter For fine adjustment of the 100 you can use the input gain control of the transmitter s exciter In the daily use of the processor probably the indicators of modulation of needle type overpass the 100 This can be due to over impulses of the ballistics or to that it responds to values average of sine wave and the indication is erroneous with the high processed audio Please see the following notes 3 2 2 2 Notes about FM Remember that many countries follow the recommendations on modulation of the FCC USA Recommendation 73268 indicates that the FM must stay all the high that is possible but without exceeding 100 in peaks of frequent recurrence In no case i

462dsp/FM - Solidyne

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