Altec Lansing 4948A Food Processor User Manual
Contents
1. Propagation Delay Signal LEDs amp Clip RS232 Cable Distance AC Requirements Environmental 4048A Weight Active Balanced 18K 20dBu 40dB to 12dB Active Balanced 112Q 20dBu 40dB to 12dB 1st or 2nd Order High or Low Shelf Parametric All pass 15dB Low Shelf 19 7Hz to 2kHz High Shelf 3 8kHz to 21 9kHz 15dB 30dB 19 7Hz to 21 9kHz 1 96 Octave Steps Four Octaves to 1 64 Octave 0 deg at low freq 180 deg at selected freq 360 deg at high freq 0 682 milliseconds 19 7Hz to 21 9kHz Off 12dB Oct Butterworth 12dB Oct Bessel 12dB Oct Linkwitz Riley 18dB Oct Bessel 18dB Oct Linkwitz Riley 18dB oct Butterworth 24dB Oct Butterworth 24dB Oct Bessel 24dB Oct Linkwitz Riley 20dBu to 20 dBu 1 2 1 to INF 1 0 5ms dB to 50ms dB 10ms dB to 1 Second dB 20Hz to 20KHz 0 25dB lt 0 01 1KHz 20dBu gt 110dB 20Hz 20KHz unweighted 48KHz 1 46mS Inputs 20dBu Clip Mute Outputs 20dBu 0 Limit Threshold Clip Mute Up to 1300 ft 400m using high quality cable Universal Power Supply 85 265VAC 50 60Hz 30W max 40 F 120 F 4 C 49 C Non condensing 8 165 3 6kg shipping 6 lbs 2 7kg net ALTEC LANSING 17 Operating Manual 4048A digital signal processor 11 DIMENSIONS 1 75 44 5 1 50 38 0 25 6 4 Altec Lansing 4048A Digital2. 7 3g Delay In large installations or outdoor venues there are often many speakers in vari ous locations to get the best coverage possible Since sound travels relatively slow through air 1130 ft s at 20 C multiple loudspeaker locations can create a situation where the original audio signal simultaneously leaving all loudspeakers arrives at a single point in the venue at several different times Needless to say this causes prob lems and what may be crystal clear sound directly in front of any one loudspeaker can be unintelligible at the farther reaches of the venue with direct line of sound to multiple loudspeaker sources The solution is to delay the audio signal to the loudspeakers located further away from the primary source so that sound comes out of the distant loudspeakers at the exact time that sound from the main loudspeakers arrives Within the 4048A up to 682 milliseconds of time delay are available on each output channel allowing secondary loudspeakers to be time aligned with the primary speakers up to 771 feet 235m away A second application for delay is to time align discrete drivers within a cabinet or cluster For example a typical three way speaker cluster would have low end midrange and high frequency drivers Short Time Delay For Driver Alignment lt gt Example 12 Inches Long Time Delay For Remote Speakers Speaker on Main Stage Secondary Speaker 200 ft from Main Stage Same
3. soft ware for Windows The 4048A utilizes state of the art DSP technologies beginning with 24 bit 48kHz delta sigma A D convert ers with 128x oversampling Audio processing includes Gain Parametric EQ Signal Routing Crossover Functions Time Delay Compressor Limiter and Polarity Invert all taking place in twin high performance Motorola DSP proces sors D A conversion uses 24 bit delta sigma converters with 128x oversampling All input and output connections are precision balanced and RF protected using Euro Block style two piece terminal block connectors 2 UNPACKING As a part of our system of quality control every Altec Lansing product is carefully inspected before leaving the factory to ensure flawless appearance After unpacking please inspect for any physical damage Save the shipping carton and all packing materials as they were carefully designed to minimize the possibility of transportation damage should the unit again require packing and shipping In the event that damage has occurred immediately notify your dealer so that a written claim to cover the damages can be initiated The right to any claim against a public carrier can be forfeited if the carrier is not notified promptly and if the shipping carton and packing materials are not available for inspection by the carrier Save all packing materials until the claim has been settled 3 AC POWER REQUIREMENTS Note The AC power switch for model 4048A is on the back pa
4. and controls cannot be changed 3 No sound Check to see if the input or output is muted Is the input or output Gain turned down Check the selected audio source s for each output making sure there is signal applied to the designated input s If used as a crossover make sure the high pass filter HPF is set to a lower frequency than the low pass filter LPF for a given output 4 Clip light stays on Is the input signal too high Check to see that the nominal input level is OdBu allowing 20dB of input headroom Are input or output gain settings too high Check to see if an EQ filter has too much boost 5 Distorted sound but no Clip LED Check individual EQ filters to see if there is excessive boost 6 Muffled sound If expecting full range audio on an output make sure the crossover settings are not inadvertently set so as to limit the pass band 7 Excessive Noise An input signal level or an input gain setting that is too low could require the loss to be made up for at the output gain stage producing more noise than a properly set up gain structure Do not use the 4048A for dramatic increases in level but rather optimize the signal source for a nominal OdBu output 8 Forgot the password See section 8 4 9 2 RS 232 Troubleshooting Tips 1 Test all data cables Use standard RS232 data cables with all conductors wired straight through Monitor cables and Null Modem cables will not work ALTEC 16 LANSING Operating M
5. 1st Order Filter end Order Filter High Shelf The EQ functions on all four inputs and eight outputs are switched in or out on 27 an individual channel basis In other words 27 34 each input or output has one switch for all of its EQ filters If certain filters are not go ing to be used within a channel simply leave gain for that filter at 0 0dB and the filter GOGH mE HAR will have no effect 4048A Shelving Filters 20dB All Pass filters The all pass filter type always has a flat frequency response but has a second order phase response The all pass phase response is 0 degrees at low frequencies and 360 degrees at high frequencies and is 180 degrees at the center frequency selected 7 3e Routing Any of the four inputs can be equally routed post input gain EQ to any or all of the eight output channels Click on the lt Routing gt box for a given input and select the desired outputs from the list of check boxes Color coded connect lines provide a visual image of the 4048A routing scheme 7 3f HPF LPF Bandpass or crossover functions on the 4048A are available only on the eight output channels Every channel s crossover consists of a high pass filter HPF and a low pass filter LPF along with the frequencies and filter types used Each outp
6. 3EIEI 12 3EIEI 3EIEI 3EIEI 12 5E EL ELE 500 500 5005 5005 88 6 oE E EE 3000 SEE 0 5880 o 5 o SEEBEBE 12 EIE 6 1 200 200 1200 1200 12EIEI 6 A2E ELE 18 88 12 8 00 12 8 00 12 1 BB 12 18 00 12 18 00 12 ASE ELE E 24 00 18 24 88 12 24 00 18 24 D0 18 24 0 18 24 00 18 24E E 18 24 900 24 0 24 30 0 24 30 2 30 0 24 0 24 30 E E 24 308 E E E 26 0 36 36 EJEI 30 36 30 36 EJEI 30 36 EJEI 30 26 00 30 2E E E E 52 EIEI 42 52 2 42 42 42 42 200 2 ALTEC LANSING Operating Manual 4048A digital signal processor 7 3 Audio Functions Editing of audio controls is done through the use of scroll bars numerical entry various keyboard shortcuts or by visually dragging filter points in the frequency response window Ease of use especially in the frequency response window makes it possible for fast potentially destructive mistakes so plan carefully before making radical gain or filter changes 7 3a Keyboard Mouse Shortcuts Convenient shortcuts allow for quick setups or edits and are shown as follows Mouse shortcuts in the frequency response window Right Click and Drag Change Q Width Left Click and Drag Change Frequency Left Click and Drag Change L
7. 6 n perdus 50 G0Hz 20W 5 3 Contact Closure Connector There are no user controls on the 4048A making it ideal for permanent installations where security is an issue There may be times however where audio system adjustments must be made in response to real time acoustic changes such as room size For these types of changes the 4048A offers the ability to recall up to eight different presets using contact closures Contact closures are nothing more than external user installed switches that when closed recall a previously defined preset which at once applies changes to the settings of all inputs and outputs The switches can be anything from a rotary switch on a control room panel to automatic door sensors located throughout conference center to a microphone key switch etc Contact closures allow for flexibility while maintaining a high degree of system security To use contact closure switching up to eight presets 1 8 must first be defined according to the needs of the installation Switches are to be configured so that closing the switch contact triggers the preset recall event Either momentory or latching switches may be used where the trigger event is the transition from open to closed for a given circuit Closing a circuit will automatically override any previously recalled presets Up to eight switches can be used with all switches sharing a common ground connection Each pin number above the contact closure connector corre
8. Bands of Inj 12 dB Linkwitz 6 Bands of 0682ms Phase Parametric annels Parametric 1st Order LS o Oui s 1 Invert 2nd Order LS 1st Order HS Output Limiter Limiter Link 2nd Order HS ALTEC LANSING 19 Operating Manual 4048A digital signal processor ALTEC LANSING Altec Lansing Professional 1000 W Wilshire Blvd Suite 362 Oklahoma City OK 73116 USA A division of Altec Lansing Technologies Inc Milford PA 18337 0277 Made In USA Printed in USA 4048A 0 0503
9. Signal Processor Q 0 00 0 00 0 25 6 4 12 WARRANTY INFORMATION 1875 476 40 19 00 483 so 152 The unit you have just purchased is protected by a limited five year warranty For warranty service or to obtain a return RMA number please call Altec Lansing technical services at 405 848 3108 Fill out the information below for your records 18 Serial Number Dealer Date of Purchase Dealer s Address Dealer s Phone Salesperson ALTEC LANSING Operating Manual 4048A digital signal processor 13 BLOCK DIAGRAMS HpfL pf H EG H Delay H Gain H Limiter H Mute 1 M G EQ R A pp ERI ETE s CI HpfLpf H EG H Delay H Gain H Limiter H Mute Fe CFS HpfL pf H EG H Delay H Gain H Limiter H Mute G EQ R B puse A 5 Ck H EQ H Delay H Gain H Limiter H Mute 4 HpfL pf H EG H Delay H Gain H Limiter H Mute 5 Mute H Gain H EG H Route H CF H EQ H Delay H Gain H Limiter H Mute 6 HpfLpf H EQ H Delay H Gain H Limiter H Mute 7 G Q Ure pep uw poe LS Hpfl pf H EG H Delay H Gain H Limiter H Mute 8 Inputs Altec Lansing 4048A Block Diagram Outputs rp Software Output Meters Output Channels 1 8 Indicator Xover HPF LPF Output Output Output 12dBBWorth EG Delay Gain 8
10. This file can then be written back to the same or another 4048A using Download Bulk Preset Dump When a Bulk Preset Dump download to a 4048 is complete the display shows a lower case d to confirm the event 8 3 Copying Settings to Another Input Or Output The Copy Paste functions are used to quickly transfer all settings from one currently selected input or output within the 4048A to another input or output channel within the same unit An example of how this might be used is with stage monitors Suppose there are eight monitor mixes on stage and they all use the same type of floor wedge The first monitor could be set up with Gain EQ and Limiting then those settings could be quickly copied to ALTEC LANSING 15 Operating Manual 4048A digital signal processor the remaining seven monitors providing a consistent starting point for each mix To copy first select the input or output to copy from then click lt Edit Copy gt then click on the input or output to copy to clicking lt Edit Paste gt to complete the action 8 4 Security There are two levels of protection assignable to the 4048A within the software lt Security gt pull down menu The first level lt Lock Processor Presets gt allows the user to edit any settings or recall new presets but not to save changes The second level lt Lock Processor gt locks all controls for the 4048A and disallows saving or recalling new channel presets To unlock a security lev
11. a maximally flat group delay Stated another way Bessel filters have the most linear phase response When a Bessel HPF and LPF of the same crossover frequency are summed the combined response is 3dB for 12dB oct and 18dB oct Bessel filters and 3dB for 24dB oct Bessel filters One of the outputs must be inverted when using either 12dB oct or 18dB oct Bessel crossover filters or else the combined response will have a large notch Linkwitz Riley The 12 dB oct and 24dB oct Linkwitz Riley filters individually are always 6dB at the displayed crossover frequency however the 18dB oct Linkwitz filters individually are always 3dB at the displayed crossover frequency The reason for this is that Linkwitz Riley filters are defined in terms of performance criterion on the summing of two adjacent crossover HPF and LPF filters rather than defined in terms of the pole zero characteristics of individual filters The 18dB oct Linkwitz Riley individually are 18dB oct Butterworth filters in that they have Butterworth pole zero characteristics and also satisfy the criterion for Linkwitz Riley filters When a Linkwitz Riley HPF and LPF of the same displayed crossover frequency are summed the combined response is always flat With 12dB oct Linkwitz Riley crossover filters one of the outputs must be inverted or else the combined response will have a large notch at the crossover frequency ALTEC LANSING 13 Operating Manual 4048A digital signal processor
12. at the crossover point 24dB octave Linkwitz Riley filters produce a flat transition through the crossover region assuming both overlapping filters are set to the same frequency slope and response type 24dB oct Linkwitz Riley filters are the industry standard the easiest to use and the filter type recommended by Altec Lansing Other filter types are available but may require polarity switching or other adjustments for proper results The following paragraphs offer a summary of the three filter types as used in the 4048A processor ALTEC 12 LANSING Operating Manual 4048A digital signal processor m Output 1 High Pass 20 46 Type Linkwitz 24 Frequency Output 1 Low Pass gt Linkwitz 24 40 dB 0 dB 20 dB Frequency 2 707 1 Hz 80 dB n 20Hz 200Hz 2KHz 20KHz Butterworth Butterworth filters individually are always 3dB at the displayed crossover frequency and are used because they have a maximally flat passband and sharpest transition to the stopband When a Butterworth HPF and LPF of the same crossover frequency are summed the combined response is always 3dB With 12dB per octave Butterworth crossover filters one of the outputs must be inverted or else the combined response will result in a large notch at the crossover frequency Bessel These filters as implemented on the 4048A are always 3dB at the displayed crossover frequency Bessel filters are used because they have
13. bandwidth filter through a problem feedback area with just a slight boost is a quick way to find the exact frequency causing trouble Once the offensive frequency has been found cut the filter s level and then adjust the bandwidth as narrow as possible while still eliminating the feedback problem Bandwidth is adjustable from about 1 64 octave to four octaves and the lower the bandwidth the less audible the filter action will be Finding the problem frequency is relatively easy but finding the best combination of cut and bandwidth takes a little practice Again it is well worth the time getting comfortable with the notching procedure so that problems can be quickly addressed with a sufficient but minimal amount of correction ALTEC LANSING 11 Operating Manual 4048A digital signal processor Shelving EQ filters 1st order filters use a gentle 6dB per octave slope while 2nd order filters use a 12dB per octave slope for more a pronounced boost or cut All shelving filters have a boost cut range of 15dB Low shelving filters have a frequency range from 19 7Hz through 2kHz and the high shelving filters range from 3 886kHz through 21 9kHz Shelving filters are most useful as broad tone controls to boost or cut the high Low Shelf end or low end of an audio signal s frequency content Because they affect a wider spec trum of audio they not as suitable for 7 feedback control as parametric filters
14. signal limiter threshold and clip The green signal LED indicates 20dB output level The amber limiter threshold LED depends on settings established within Altec Lansing Software and assuming the limiter is active indicates that sufficient signal level has been reached for the limiter to begin the process of gain reduction Clipping occurs at 20dB and is indicated by a red LED The red output mute LED becomes lit when an output channel is turned off through software control 4 3 Preset Indicator This display indicates the currently selected preset number 1 18 for the 4048A This display also indicates the following operating conditions within the 4048 Firmware revision number is displayed during power up and when a factory reset is aborted Factory reset countdown which occurs by pressing and holding the factory reset switch during power up Contact closure event confirmation is indicated by an upper case C for a few seconds followed by the active contact preset number 1 8 RS 232 bulk preset dump completion is indicated by a lower case d If the 4048A receives a corrupt RS 232 dump an upper case E is shown 4 4 Factory Reset Switch This is a recessed switch in the small hole below the preset display This recessed switch is used to perform a factory reset by pressing and holding during power up Note that a factory reset will erase all user defined presets stored in the 4048A including the user password 4 5
15. tri angle is intended to alert the user to the presence of uninsulated dangerous voltage within the product s enclosure that may be of sufficient magnitude to constitute a risk of electric shock to persons Operating Manual 4048A digital signal processor CAUTION RISK OF ELECTRIC SHOCK DO NOT OPEN TO REDUCE THE RISK OF ELECTRIC SHOCK DO NOT REMOVE COVER NO USER SERVICEABLE PARTS INSIDE REFER SERVIC ING TO QUALIFIED SERVICE PERSONNEL TO REDUCE THE RISK OF FIRE OR ELECTRICAL SHOCK DO NOT EXPOSE THIS APPIIANCE TO RAIN OR MOISTURE TO REDUCE THE RISK OF FIRE REPLACE ONLY WITH SAME TYPE FUSE REFER REPLACEMENT TO QUALIFIED SERVICE PERSONNEL WARNING The exclamation point within an eqilateral triangle is intended to alert the user to the presence of important operating and mainte nance instructions in the literature accompanying the device THIS APPARATUS MUST BE EARTHED ALTEC LANSING Operating Manual 4048A digital signal processor C RS 232 Dataport LU Input Channels e Qo Qo Preset eo 3 0 3 0 1 INTRODUCTION Your new 4048A is a flexible four input eight output digital signal processor capable of precise control of a broad range of audio functions Because it has no user controls it is ideal for applications where real time changes are unlikely or when tamper proof security is required All adjustments are made using Altec Lansing Maestro
16. ALTEC LANSING PROFESSIONAL 4048A DIGITAL SIGNAL PROCESSOR T amp 048A m DIGITAL SIGNAL PROCESSOR RS 232 Dataport JUL Input Channels Output Channels 2989 Preset OO 2 1 DO Q Q Qo 00 ALTEC LANSING Altec Lansing Professional 1000 W Wilshire Blvd Suite 362 Oklahoma City OK 73116 USA A division of Altec Lansing Technologies Inc Milford PA 18337 0277 Made In USA Operating Manual 4048A digital signal processor TABLE OF CONTENTS 1 INTRODUCTION edo 23 god 20208074 9 se bee tocca 4 2 UNPACKING th ER RE EAE EE 4 3 AC POWER REQUIREMENTS 22 22 2 4 4 FRONT PANEL FEATURES ssi rm R RR ERAS RI Ie RES 5 5 REAR PANEL FEATURES 2 2 ox YR DOR Y an 6 6 ALTEC LANSING MAESTRO M SOFTWARE 8 7 GETTING STARTED 12224552495 v2 ddr 9 8 OTHER SOFTWARE FUNCTIONS 15 9 TROUBLESHOOTING TIPS Ca a E 16 19 SPECIFICATIONS 1324007629 ca Secure Eae aca ac 17 11 DIMENSIONS 1442542523399 dro ora 18 12 WARRANTY INFORMATION 18 13 BLOCK DIAGRAMS cee eee eae e ga ea en 19 ALTEC 2 LANSING The lightning flash with arrowhead symbol within an equilateral
17. RS 232 Dataport The 40484 has two parallel RS 232 dataports one on the front panel and one on the back for connecting to a computer for software control See section 6 3 for details on connecting to a computer ALTEC LANSING 5 Operating Manual 4048A digital signal processor 20 4048A DIGITA inputs 0 Outputs 1 8 rB434 rea r24 r34 r4 4 r53 OG 0G HAMOG HOG WOGWOG 0 0 Go oO Connect to G if Unbalanced Input is Used Outputs Can Be Used Balanced Go Unbalanced Connect to G if Unbalanced Out 5 REAR PANEL FEATURES 5 1 Input Connections Balanced input signals are connected to the 4048A using the included Euro Block connector flat blade screwdriver is required to connect a stripped wire lead to the loose connector which is then inserted into the rear panel Euroblock receptacle It is important that both and inputs are properly terminated or signal loss and noise may result In other words if an unbalanced input signal is used con Euroblock Fis nect the signal to the input and connect the ground wire to both
18. anual 4048A digital signal processor 2 Use a valid PC serial port You must use a serial port that is not opened to any other application such as a mouse modem or another program To verify that the port exists look in Control Panel System Device Manager Ports While you re there make sure that the port has no warnings or conflicts There is no need to change the port settings because Maestro Software will do this automatically Finally you must select the valid port in software This is done under the Communications heading Com Port Assignment 10 SPECIFICATIONS Inputs EGRE ERES Max Input Level Input Gain Range Outputs ore Ra Max Output Level Output Gain Range EQ EQ Filter Shelving Filter Boost Cut Range Shelving Filter Frequency Range Parametric Filter Boost Cut Range Parametric Filter Frequency Range Parametric Filter Bandwidth All pass phase shift Delay Output Delay Crossover HPF and LPF Frequency Range Available Filter Types Limiter Threshold Range Ratio Range Attack Time Range Release Time Range Frequency Response CHD ise Dynamic Range Audio Sampling Rate
19. e connection should now be established RS 232 signal will run typically to 1300 feet using high quality cable ALTEC 8 LANSING Operating Manual 4048A digital signal processor 7 GETTING STARTED 7 1 Configuration Options Altec Lansing Maestro Software for the 4048A includes 10 permanent default configurations which can be used as starting points for setting up user defined presets Modified configurations can then be saved to either disk filename alp or one of 18 memory locations on the 4048A Load a default setup by clicking lt Configuration gt within the lt Options gt menu The default configuration options are 1 4 x 2 way Crossover 2 2 x 3 way and 2 Aux 3 2 x 3 way mono sub 4 2 x 4 way Crossover 5 1 x 5 way and 3 Aux 6 Mono Distribution 7 Stereo Distribution 8 LCRS with mono subs 9 4 x 4 Processor 10 Muted Flat Start up 7 2 Metering Options The front panel LEDs on the 4048A indicate signal present 20dBu OdBu inputs only or clip 20dBu For more detailed level information Maestro has a separate metering window showing all four inputs and eight out puts including gain reduction meters for output limiters Meters can be set to dBu or VU in the Options menu 0 VU 4dBu 1 228Vrms 7 Maestro 4048A Meters CUI X 8 ABCD 1 2 3 4 5 amp 7 PKE GOB Th ADF Pk EIE Tn BP A42bE E ELE 0012 30 12 3EIEI 12
20. e time ranges from 10ms dB through 15 4 A very fast attack time can sound unnatu ral while a very long attack time can miss some of the initial transient Similarly a very short release time can make the audio sound uneven while a very long release time can create pumping or breathing characteristics depending on the kind of signal Experiment to find the best solution for a given application Limiter linking is used to group the compressor limiter action of multiple output channels Selecting lt Link gt within the output limiter section ties that channel to the link bus which in turn applies the same degree and charac teristics of gain reduction to all channels assigned to the link bus The linked channel with the highest signal level above threshold determines the gain reduction on the other linked channels A prime example involves stereo signals Using limiter linking the limiter action on both channels will track perfectly based on the loudest signal on either channel eliminating a level mismatch in the stereo image 8 OTHER SOFTWARE FUNCTIONS 8 1 Channel Preset File Management As discussed in section 7 2 there are 10 standard configurations which can be modified to create user defined preset files These modified presets can then be saved to either disk or the 4048 itself For disk files the file extension is lt alp gt For files saved to the 4048A they must number from 1 to 18 and the filename must be no more than 20 c
21. el simply re enter the password within the lt Security gt pull down menu Passwords are case sensitive The password is stored internally in the 4048 s non volatile memory for greater security If the password is forgotten control access to the 4048A can only be acquired by performing a factory reset see section 8 5 8 5 Factory Reset Factory reset is used to clear all user defined preset names and control values and reset them to their original factory settings Factory reset also clears the password and allows full control access to the 4048A Factory reset to the 4048A is accomplished by pressing and holding the recessed tact switch beneath the Preset LED display on the front panel during power up There will be a countdown on the display to indicate a factory reset is occurring Releasing the switch or shutting off power at any time during the countdown will stop the factory reset from occurring At the end of the countdown a successful factory reset is indicated by a lower case r in the display followed by normal operation of the unit 9 TROUBLESHOOTING 9 1 Audio Troubleshooting Tips 1 No power Is the detachable AC cord fully plugged in Is the rear panel power switch on 2 Software controls don t work Is the RS 232 cable properly installed to the PC Is the software commu nications enabled Is the correct Comm port selected Check the security level section 8 4 If set to lt Lock Proces sor gt then unit is view only
22. eset 1 4 x 2 way Crossover File Edit Communications Mute Options Security Help imiter o o imiter Limiter imiter imiter Limiter Limiter Limiter Limiter gmi CH CHC EA DB y Limiter B Mute Dutput 1 High Pass 5 20 46 Tupe Linkwitz 24 0dB Frequency j 19 7 Hz 20 dB Output 1 Low Pass gt Linkwitz 24 Freguency z 1000 0 Hz 6 1 Installing Software The Maestro installation program is the same whether from the web site or from a disk To install the software double click on setup exe and follow the installation instructions 6 2 Connecting the 4048A to a computer A standard D Sub nine pin female to male connector cable is used to connect the PC to the 4048A If the PC lacks a nine pin RS 232 port an active USB to RS 232 converter can be purchased at computer stores Following are the suggested steps for connecting the 4048A to a PC 1 Plug the RS 232 cable into an available serial port on the PC 2 Plug the other end of the cable into either the front or back RS 232 Dataport on the 4048 3 Turn on the power to the 4048A 4 Open Maestro software 5 Go to the Communications menu click CommPort Assignment and select the Comm port being used 6 Go to the Communications menu and select Enable Communications 7 Th
23. evel Keyboard shortcuts i Change to last input used Change to last output used Change the order in which parametric and crossover filters are scanned Change to the Delay frame Change to the Gain frame Change to the EQ frame Change to the Routing frame Change to the HpfLpf frame Change to the Limiter frame Mute the current input or output channel ESC while dragging a filter Resets the filter position to its starting position Cut Active Filter 7 Zero Active Filter Ctrl c Cut Master Gain Ctrl z Zero Master Gain 7 3b Mute The 4048A allows the user to mute all inputs or outputs When muted an input or output s red Mute LED is lit To mute or unmute all outputs simultaneously click on the Mute menu heading and select the Mute all or Unmute all gt option Inputs can be muted or unmuted one at a time Additionally when recalling a new preset to the 4048A the user is prompted to mute all outputs as a new preset can introduce dramatic changes to the system configuration 7 3c Gain Guipul 1 Gam For best signal to noise performance provide an input signal with a nominal OdBu level Using significant input or output gain to make for a weak input signal compromises the noise performance of the 4048A I Polarity eda 4 Input and Output Gain are separately adjustable from 40dB to 124 Due to limi a giam tations within the graphical interface fi
24. haracters The 18 preset locations on the 40484 are initially filled with the same 10 standard configurations repeat ing two times A preset file contains the control parameters of all four inputs and eight outputs For a written record of all parameters of a specific preset file click Print Channel in the File menu Since there are no user controls on the 4048A the only way to load channel presets is by using Altec Lansing Software to recall files saved on either the PC or the 4048A The exception to this is through the use of contact closures where presets 1 8 from the 4048A memory can be loaded using switches wired to the rear panel contact closure connector block see section 5 4 Note preset recall event will overwrite any changes to the working channel so be sure the current configu ration is saved before continuing or it will be lost The 4048A always loads the last working channel on power up so as to preserve any changes should the power be inadvertently turned off prior to saving a channel Caution A new preset may have dramatically different settings capable of damaging sound system compo nents so be careful not to recall the wrong preset while the system is on be safe always select Yes to mute all outputs 8 2 RS 232 Bulk Preset Dump To capture the entire set of 18 presets stored within a specific 4048A s memory a lt dmp gt file is created clicking Trigger Bulk Preset Dump within the file menu
25. le not fixed and that the bandwidth or how wide the filter affects the frequency spectrum at the center frequency is completely variable The smaller the bandwidth the less the audio signal on either side of the frequency center is boost or cut whereas a larger wider bandwidth produces an audible change to the overall tone of a signal Paramet ric filters are best used to hunt down and eliminate problem feedback frequencies add or remove a characteristic hot spot from microphones or clean up room resonance situations It is well worth the time becoming proficient with parametric EQ filters as they offer the best solution to many EQ problems Narrow Low Bandwidth Wide High Bandwidth 420dB uu 1008 10dB 20dB 30dB 0 20Hz 200Hz 2KHz 20KHz 4048A Parametric Filters 4048A parametric filters have a boost cut range of 15dB to 30dB There is more cut than boost because one of the more common uses for parametric filters is to dramatically cut or notch out very narrow frequencies low bandwidth in order to eliminate system feedback problems Every instance of a parametric EQ filter has a center frequency selected The factory default is IKHz but each filter s center frequency is adjustable from 19 7Hz to 21 9kHz in 1 96 octave steps Carefully sweeping a narrow
26. maging loudspeakers manage analog and digital recording levels optimize broadcast Limiter C levels or thicken the sound of an audio source compression The adjustable parameters include Limiter In Out Threshold Ratio Attack Time Release Time and Limiter Link 21 D E u The limiter threshold range is from 20dBu to 20dBu This setting determines the Ratio signal level above which gain reduction begins and is indicated by the amber LED S L in m Infinite the output meter section Increases in audio level above the threshold will be reduced ac s Attack cordingly by the ratio settings E E 5 ms dB The ratio control determines the amount of gain reduction above limiter threshold Release Ratio ranges from a gentle 1 2 1 to a brick wall INF 1 To illustrate how the ratio control m 100 ms dB works imagine a commonly used loudspeaker protection ratio of 10 1 which means that for every input signal increase of 10 dB above threshold the output level will only increase by 1dB The higher the ratio the more pronounced the audio effect so use the lowest ratio possible to sufficiently address the problem ALTEC 14 LANSING Operating Manual 4048A digital signal processor Attack and Release settings adjust the time it takes the limiter to engage and then disengage when the signal increases above threshold and then subsequently falls back below threshold Attack time is adjustable from 0 5ms dB through 50ms dB while releas
27. ne tuning gain settings in 0 14 steps is accomplished using the up down arrows on the keyboard Changes of exactly 1dB are quickly accom xim plished using lt PageUp PageDown gt buttons To instantly return a gain setting to OdB press Ctrl Z see other keyboard shortcuts in 7 3a Additionally The output gain menu is also used to invert the polarity of outgoing signal for that channel anam ALTEC 10 LANSING Operating Manual 4048A digital signal processor 7 3d EQ Each input and output of the Altec Lansing 4048A Input A EQ Output 1 EQ _ processor has its own EQ section offering full parametric EQ EQ E d s four types of shelving filters and an all pass filter Input channels have eight selectable EQ filters while output chan ue Eiker Tee nels have six selectable EQ filters On all inputs and outputs Parametric Parametric each EQ filter is selectable between parametric PEQ Ist Level Level order Low Shelf LS1 2nd order Low Shelf LS2 1st order z 0 0 dB High Shelf HS1 2nd order High Shelf HS2 and Frequency Frequency Pass filter AP pues 23 mi Bandwidth Bandwidth 74 cn cn e co pm Parametric EQ PEQ uses peak filters with the ability to control boost or cut frequency center and band width Think of one band of parametric EQ as a single graphic equalizer fader except that the frequency is variab
28. nel The Altec Lansing 4048A uses a universal input power supply which will accept any line voltage in the range of 80VAC to 260VAC 50 60Hz and is exceptionally resistant to voltage dips or brown outs A standard IEC 320 grounded AC inlet is provided on the rear panel to accept the detachable power cord Never remove the AC earth ground connection to the 4048A In the event of an internal fuse failure refer the product to a qualified service technician for fuse replacement replacing only with the same type and rating fuse 0 5A time delay Littlefuse 218 500 or equivalent ALTEC 4 LANSING S L Mute S L Mute S L Mute S L Mute S L Mute L Mute S L Mute S L Mute LAN S I N G 9 9 0 0 0 00 9 9 9 9 Operating Manual 4048A digital signal processor 4048A DIGITAL SIGNAL PROCESSOR ALTEC Output Channels CO 4 FRONT PANEL FEATURES 4 1 Input Channels The 4048A has four input channels each of which can be routed to any combination of output channels Each input channel s three color Sig LED indicates input signal level of 20dB green OdB amber and 20dB clip red respectively Note that the Sig LEDs detect actual signal at the input connections before any gain adjustments are made within the 4048A The red input mute LED becomes lit when an input channel is turned off through software control 4 2 Output Channels The eight output channels on the 4048A have three color LEDs to indicate
29. sound arrives at two different times Fix by delaying secondary speakers 177mS all located near one another The different drivers A E 2 High No Delay gt Midrange Delay 12 Inches 5 2 N lt gt Example 8 Inches gt Low Delay 8 Inches 0 6mS for each frequency band are not necessarily the same physical depth with respect to the front of the loudspeaker cluster so there exists the problem of the same signals at the crossover points arriving at the cluster wavefront at different times creating undesirable wave interaction such as frequency peaks or cancellation The solution in this case rather than fixing the frequency anomalies with EQ is to slightly delay the signal to the drivers closest to the cluster front Using the location of the driver diaphragm farthest back as a reference point measure the distance to other drivers in the cluster and set the output delay for each accordingly with the driver diaphragm closest to the front getting the longest delay and the driver at the very back getting no delay at all The minimum adjustment is 0 02 milliseconds or about 4 inch When appropriate always time align the loud speakers before applying EQ to the outputs of the 4048A 7 3h Limiter A full function compressor limiter is included on each output channel A limiter is commonly used to prevent transient audio signal spikes from Output 1 LET da
30. sponds to the number of the preset which will be recalled when that switch is closed Always use the 4048A contact closure ground for contact closure switches Do not connect the 4048A contact closure ground to any other external grounds as ground loop currents may result 5 4 RS 232 Dataport D Sub 9 Pin Female RS 232 Pin Out The 4048 has two parallel RS 232 dataports one on the front panel and one on the back for connecting to a computer for software control See section 6 3 for details on connecting to a computer 5 3 5 5 Inlet and Power Switch tame Not Connected Transmitted Data Received Data Data Terminal Ready tied to pin 6 Ground Data Set Ready tied to pin 4 A detachable AC power cord is used on the 4048A Since the internal universal power supply works from 80 to 260 VAC 50 60Hz the only change necessary for use with international power is the appropriate AC power cord The AC power switch is found on the back of the unit as well Not Connected Not Connected Not Connected o0 00 30m ALTEC LANSING 7 Operating Manual 4048A digital signal processor 6 ALTEC LANSING MAESTRO SOFTWARE Altec Lansing offers a powerful software interface for the Windows PC environment providing control for the 4048A digital signal processor All controls are intuitively represented in a user friendly way and on line help is available for key functions 7 Maestro 4048A Pr
31. the Connector and ground connection System A Note About Input Signal Levels There are no input trim adjustments the 40468A therefore all the processing including gain is done in the digital domain As a consequence of this design philosophy it is important to feed the processor with the proper nominal signal level to achieve good signal to noise performance as well as headroom before clipping The 4048A is designed to clip at signal levels above 20dBu 7 75Vrms which places the noise floor lower than 90dBu The optimum input signal level which should be fed into the processor is OdBu 775Vrms This input level will allow 20dB of headroom while giving a nominal signal that is gt 90dB above the noise floor 5 2 Output Connections Like the inputs output connections are made using the included Euroblock connector All outputs are elec tronically balanced and may be wired balanced or unbalanced For unbalanced outputs connect the shield to both and G terminals ALTEC 6 LANSING Operating Manual 4048A digital signal processor SIGNAL PROCESSOR AC 1 4 Max On 8 Preset Recall DEB 1 req Contact Closure 300G 1 2 3 4 5 6 7 8 6 chy 75116 Milford PA 18357927 Madein USAT obs oO 5 232 Data ort Risk of Electric 80 240VAC
32. ut s crossover section is essentially a bandpass filter making it necessary for the user to map out ahead of time which outputs will be used for the various frequency bands and set the overlapping filter frequencies and types accordingly Note The HPF determines the lower frequency limit of the signal while the LPF determines the upper frequency limit The frequency range for the high pass filter HPF is from 19 7Hz to 21 9kHz with an option to turn the filter off at the low end of the frequency selection The low pass filter LPF offers the same frequency range with the off option at the high end of the frequency selection There are eight types of filters available in the crossover section each suited to a specific preference or purpose The slope of each filter type is defined by the first characters in the filter type 12dB 18dB or 24dB per octave The steeper the slope the more abruptly the edges of the pass band will drop off There is no best filter slope for every application so experiment to see which one sounds most pleasing in a specific system The pre loaded presets all use 24dB octave filters in the crossover section but of course they can be changed to suit the application In addition to the frequency and slope crossover filters can be selected as having Butterworth Bessel or Linkwitz Riley response These refer to the shape of a filter s slope at the cut off frequency affecting the way two adjacent pass bands interact
Download Pdf Manuals
Related Search