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1. RE OE embedded mi Saved 7 14 15 16 17 18 19 20 21 mpl 125 180 8 120 180 a Sampling Hz 1 k 110 120 Correct With Driver On MLS Length WM Output Port 2 262143 20 a5 60 Room EQVPlotting Controls 40 Threshold 0 dB 85 20 W Show Measured Phase 80 O Show Room Phase fo ae Show Room EQ SPL 72 Equalized Room SPL 65 0 o AE Room Frequency Range 58 100 From 200 Hz 200 0 Hz 5 120 45 140 Projected Slope Below dB 4D 160 10 00 Scalar Average 38 180 3 dB deg Amplitude Only zn Re C alculate 320 m Global Function Conrols ah Bypass Room 220 200 Clear Data 180 160 140 120 Done GD 40 20 Cancel Controlled Acoustic Bass System CABS described by Nielsen in http vbn aau dk files 62729248 LF sound field control pdf Greate and maintain a plane wave propagating from front to rear When the plane wave hits the rear wall another set of loudspeakers close to the wall will create a delayed version of the frontal signal but in opposite phase and with a proper gain so the reflection at the rear wall will be cancelled Front Left Subwoofer Front Right Subwoofer m kawaka d MOM TUM Ja Amplitude DIE nverted phase Delay propor2. GC XQ KO XC W h X hh Gh w NIN k W aT N Y sia MER gt i Calculating Driver s Zin Modulus Phase 1 so NEUM mr aoc is li PE ESTEER Emm asa OSOZ TEES PP ONT ER mE FE TET TEE a cl as cia x mde m x 120 gt 24 masa m m 2 T NE mos zaa e 2 3 455 8 10 2 3040 60 80100 200 300400 600 3k 4k Ek Bk1Ok 2Dk 30k40k 50k Hz UR 073 e MLS sampling frequency 48kHz so measurement data valid to 23kHz Sound card flat from 22Hz up so low frequency noise evident below 5Hz e Measured Zin modulus black curve Phase blue curve Zin extended for HBT pink curve HBT calculated phase red curve Concept of the EQ Process Multiclient Soundcard Square Wave from Gen Square Wave distorted by Driver Channel 3 Phase Reversal The Test Signal One of the most useful test signals in electronics is a humble square wave The ideal square wave Is a superposition of an infinite number o
3. 7 2 BBM System Configuration 1000 0 Hz Bessel 1000 0 Hz Fo 1000 0 Hz Fo 1000 0 Hz Bessel Fo 1000 0 Hz 7 2 HT system with BBM Fa 1000 0 Hz Bessel Mb File Loaded Ta Plot 1 20 0 Hz F2 200 0 He Bessel LP BdB act Fo 1000 0 Hz _ Gain 0 0 dB Fo 1000 0 Hz Bessel LP BdB oct File Loaded K Ta Plot Fo 1000 0 Hz Fa 1000 0 Hz Rear Right Bessel Fo 1000 0 Hz LP GdBloct 5 Fo 1000 0 Hz Bessel Fa 1000 0 Fi 20 0 Hz F2 200 0 He Gain Gain 0 0 98 7 4 HT system with CABS Side Left and Side Right loudspeakers are wideband drivers eg Dayton Audio 5220 8 8 Point Source Full Range Neo Driver 40Hz 20 000Hz 130 htto www parts express com dayton audio ps220 8 8 point source full ran Besse LP BdB oct Bessel LP BdB oct 6 Fo 1000 0 Hz 1000 0 He Front Left Bessel Bessel jour Loaded _ LP GdB oct LP GdB oct Fo 1000 0 Hz Fo 1000 0 Hz Del D 000 ms Phase Gain 0 0 dB Bessel 5 Bessel Bessel Gain 0 0 dB Bessel Border Bessel Bessel a b Loaded o Plot DER LP GdBfoct 5 Fo 1000 0 Hz Bessel LF GdBfoct GdBfoct Fo 1000 0 Hz Fo 1000 0 Hz 26 Gain 0 0 dB Bessel Bessel Outs fie Loaded LP GdB oct Fo 1000 0 Hz Fo 1000 0 Hz Fo 1
4. Phase atan Equalized System Frequency Response with Magnitude Forced to 1 la jbi a jbj Me if l then Afagnitude Phase System Inverse Phase Function magnitude red phase FIR filter can do this Phase vs Frequency 10 20 30 40 80 100 200 300 400 500 zk 3k 8k Dk 30k 40k Hz Inverting System Phase We have now created a perfect phase reversal device with flat amplitude response oystem Inverse Phase Function see figure above Flat amplitude response requirement is important here because at this stage we do not want any more amplitude corrections We have done this already in the previous stage using our HBT based Amplitude Error Function Enter loop with HBT equalized filter Filt i Filt i real Filt i imag for i 0 i lt PARTITION SIZE USED I Calculate conjugate phase filter c atan2 Filt i imag Filt i real 1 cos c real part magnitude 1 b 1 sin imaginary part magnitude 1 Substitute Filter variables before multiplication A Filt i real real part Filt i imag imaginary part Perform multiplication with conjugate jB a jb Filti real a A b B real part phase linear Filtlil imag a B b A imaginary part phase linear Conclusions two step equalization
5. A 45 40 20 20 25 0 30 20 35 40 40 60 45 80 50 100 55 120 ii is Re ar Eeft 277 ro u dB deg 10 20 30 40 60 80100 200 300400 600 1k 3k 4k Bk 0k 20k 30k 40kHz Frequency domain curve plotting screen BEM 6 0dB Diagram Editing Iv Draw ove Wipe Wire Wipe Comp Show Nodes Show Raster Test Tones Cuore selection Clear Plots 51 Use HET Data SFL Only EQ Wade Lt 21 37 1 13 1 01 11 08 Loudspeaker Management System UE6 DSP engine Filter And Yoicing Element Data X Ultimate Equalizer V5 0 C UEG xl Filter Configuration U File Import Export Data Driver Files System Design Playback Measurements Help LP 12dB aoct LF 18dB act LP 24dB oct Element cut off frequency O Circuit and Shebang 1000 0 Hz 10 000000 dB By pass This Element 0 000000 Don Large selection of built in filters LLL Lt 21 37 1 12 88 Di 10 14 Frofile Loaded After the system has been designed UE can be switched to Playback Mode UE MLS Measurement System ultimate Equalizer 5 0 C UEB DIGITAL Testing EyngAES16 5 1 Room hif File Import Export Data Driver Files System Design MLS Pracessing MLS Signal Generator Controls MLS Length Sampling Rate 282143 480
6. Lstream Not Present EM i bigtalin Digital Out 3 valid Emphasis Digital Out 4 Z Emphasi Digital In 2 Mat Present 22 En w Wali pe zi Digital 3 Not Present up E ui r AAA EUIS 1 1 all d Digital In 4 Not Present 9454 a Mon Bit 15095 BEREIT Digital Gut 7 fw valid Emphasis Digital Out 8 valid Man PCM Emphasis Setting up PWR ICE125 Amplifiers 3 1 4 Channel Mode The PWE CE 125 ruri x 2 x QUT DSP configuration and will operate under 3 modes selectable from the GUI of the plug n Channel mode channel 1 L Channel 2 R Mixed LER Channel 1 L Mono input from unbalanced Left analog XLR input 4 Digital AES input Left Channel R Mono input from unbalanced Right analog ALF input 2 of Digital AES input Fight Mixed LER Mixed Mixed input of RC unbalanced Left amp Eight analog XLR i input IE 7 or Digital AES input left amp nght 2 3 7 Digital Link OUT The digital Link QUT of the PWR ICE a buffered AES output of the Digital IM It s am AES Output allowing 2 x plate amplifiers to share Audio It could be used for a stereo configuration or dual Subwoofer NOTE The Digital Link QUT is only a buffered output of the digital Input Unless you have a digital input AES SPDIF ALR 2 this output wil
7. Show Ste oo mg Show Step 070 Inv SPL Show SPL Inv Wind Slope 40 u Iny Fwd Wind Show Zin In Ref Time domain response to 300Hz square wave mH A 300Hz Sane wave re loudspeaker i 15 highly distorted The is the result of highly irregular fre nse D zy from 1 2 0 6kHz with an Amplitude Equalizer design An advanced tool used for linearizing a transfer function of LTI Linear Time Invariant system 1 an Inverted Hilbert Bode Transform HBT technique Just like Fourier Transform allows you to flip between time domain and frequency domains the HBT allows you to move from magnitude response to phase response and vice versa can therefore nominate a frequency range of interest within the loudspeaker s magnitude response then attach flat tails on the low and high side of this frequency range and apply this artificially created magnitude response to the HBT As a result will get corresponding phase response which in turn means that actually have full complex transfer function calculated via HBT HBT Equalizer design SPL of the Amplitude Error Function thick blue line notice it s inverted already Phase of the Amplitude Error Function Please note mathematically correct phase response and it s transitions from irregular to flat sections This is the HBT in action 15 1806 oHL Phase vs Frequency
8. Summary HBT Editor Window Amplitude 71 78 dB Freg 10 0 Hz Bin N LLL EE WE LR w TU 120 NM EUN 1 NE a 100 LN LIL JA LL m m Lala a l WARE _ So ae wA x nn x E NA 1 1 120 Ce ee ea aek A xam x d AME 160 Sees uci JAJA 1 TLI z z H z z z z z z z z z z z z z z deg 10 20 30 40 an 100 200 300 400 Tk 2k 100 120 140 160 1 ELI 5 5 5 5 5 5 B deg 10 20 30 40 eo 100 200 300 400 600 1k Summary KCN BLOW id E T 4 0c imer Vernier Probe mas wd 20Hz square wave Minimum Phase Mode and Linear Phase Mode oms Impulse in Minimum Phase Mode and Linear Phase Mode minimum phase version of the subwoofer has converted the clearly asymmetrical pulse into a much more symmetrical bi polar pulse with post ringing
9. 10 160 22 MUT munnunamannananunnnamanusnnananunnnaphununnnmananmannumananannmmanuanaununanannmanamanananamnannuasnananananamunaunananananananamananananmmananuanmmanamunmuanannunanuanunnnasanunnnnannmununnununannnunamannananunnnannnnunanais ansa F ooaasnannnnunnunanunnnunamannnmmananamanammaannnananununaanamnanananamannuasnananamanananamanananananananmmananananamananauman E u dB deg p 10 20 30 40 80 100 200 300 400 600 3k dk Bk 10k 20k 30k 40k Hz Loudspeaker HBT linearized magnitude pink phase ve ow Loudspeaker remains minimum phase 10 20 30 40 60 50 100 200 300 400 zk dk 10k 20k 30k 40k Hz Square wave passed through HBT equalizing system 0 008 1 00 e P Paare Waveform of loudspeaker one Waveform of HBT equz 2 Ext Line Inverting System Phase SMITH S W 2003 Digital Signal Processing A Practical Guide for Engineers and Scientists Page 194 represented by placing a star to the upper right of the variable For example if Y f consists of Mag and Phase X f then X f is called the complex conjugate and is composed of Mag X f and Phase rectangular notation the complex conjugate 1 found by leaving the real part alone and changing the sign of the imaginary part In mathematical terms if is composed of ReX f and ImX f then X f is made up of ReX f
10. 95 95 60 30 85 85 20 m ME ME MSZE MMA 80 80 0 75 LL l l a u M 70 i120 0 el 65 65 560 60 80 55 _ lil EEREN O i I LLL i i ee 50 i 0 L lil 610 45 NE 1 i Lll l l L j L lilii 40 _ i10 Lo E E E E AR LEN 35 35 180 dB dB deg 56 8 10 20 3040 6080100 200 300400 600 1k 2k 3k 4k Ek 8 10 20k 30k40k dB deg 5 10 20 30 40 0 80100 200 300400 600 20k 0 40k Hz Loudspeaker Equalization Strategies Do not equalize frequency response at all just use UE as an active crossover and get full benefits of an active system 1 and add alignment of acoustic centres by introducing correct delays to midrange and tweeter Use built in peak notch shelving filters to provide broad equalization Up to 32 CAD elements can be used in each loudspeaker system HBI Equalize at single point on the design axis say 1meter or 2 meters This will ensure ideal equalization at this point and very good EQ along the design axis Perform multiple measurements at 15deg horizontal and use the average to equalize Horizontally symmetrical loudspeaker recommended Perform minimum phase equalization or linear phase equalization Linear phase results in much larger latency Us
11. F3dB 300 0 Hz Third F3dE 3000 0 Hz Forth 20000 0 Hz Print 4 Passive Network 2 0 ohm Hatched k ratin 333 4 Active Network 20000 0 ohm Co 002 uF Typical crossover with corrective circuits Crossover s frequency response green components optimization to selected target EB CAD Editor Horizontal 0 Vertical 0 LI 28 12500 uF 3 L1 3 601600 mH CO 28 125 1 5 602 mH 1001 19 2 445 mH L3 d 3601 60 mH n R2 100 0 uohm 812 810 6 3 ohm C8 302 669 uF R4 0 000100 ohm 8 i C5 2 812500 uF 30 00000 ohm 1 000000 ohm C8 302 6690 uF 19 2 444647 mH R10 6 320500 ohr C11 6 980000 uF 812 6 660000 ohrr D13 Driver pb I es IHE a 1 CAD Optimization Control Targets Optimization Nodes Doubleclick to Highlight gt Optimize These Items A CO 3746191 uF 011 600 023434 mH U m 000100 ohm C5 4 468191 uF 0 360160 mH 00 ohm 00 33F 1 000000 ohm Appl Abort LockALL PPY ea Zin ew BACA Osid 50 00 50 00 Accept New Values ej Print Clear Step 2596 Zin ohm Conjugate i 00 Apply 4 Error 332 4 ZinEst 64 00 Trial 183 Zmin 40 Zin
12. Step 1 Amplitude Error Function Inverse HBT Step 2 System Inverse Phase Function Conjugate with magnitude 1 MEUSE o UR 300HZz square wave runithr trgh thellbudspeaker a he Conclusions Implemented two stage equalization technique removes driver induced time and frequency domain distortions The resulting outgoing square wave is almost perfectly recombined from individual sine waves constituting the input square wave HBT based Amplitude Phase Error Function can be equally applied to smooth the magnitude and phase response of non minimum phase systems such as multi way loudspeaker system complete with Minimum phase system driver remains minimum phase and non minimum phase system loudspeaker system remains non minimum phase Also the System Inverse Phase Function inverts the phase of the complete system as it was measured and regardless of the trajectory of the phase response Consequently the whole two stage equalization technique is fully applicable to multi way loudspeaker systems Using two stage approach allows us to trade phase linearity for latency Max tolerable latency for AV lip synch is 18015 Conclusions Example of a fully equalized SPL and phase of a 2 way loudspeaker 125 125 180 120 120 150 115 DENM INJ Ni 0 3 1 OA ON DA A A E O 110 222 0 105 l L a 100
13. affect crossover performance Qes will affect Zin w Re depends on temp Practically can only correct broad irregularities Complexity of the passive circuitry needs CAD to properly analyse Unable to de couple amplitude from phase Inductors for subwoofers are large heavy and expensive Can we do better Foundations of Amplitude Phase Relationship Network Analysis and Feedback Amplifier Design By W BODE Ph D Mathesatician TELEPHONE LagozazoxiEs Inc TENTH PRINTING Dr Bode s book CONTENTS CHAPTER I AND Mopar EQUATIONS FOR AN ACTIVE CIRCUIT THE COMPLEX FREQUENCY PLANE a III FEEDBACK a IV MATHEMATICAL Deriniriow or FEEDBACK a V GENERAL THEOREMS FOR FEEDBACK VI GENERAL THEOREMS FOR FEEDBACK VII AND PHYSICAL REALIZARILITY VIII Contour INTEGRATION AND 8 CRITERION FOR STABILITY IX Representation Or Driving IMrEDANCE FUNC TIONS a m a r 7 TOPICS IN THE DESIGN IMPEDANCE FUNCTIONS XI PuysicaL REPRESENTATION OF TRANSFER lMPEDANCE FUNCTIONS XII THE DESIGN EQUALIZERS XIII GENERAL RESTRICTIONS PHYSICAL NETWORK CHARACTERISTICS AT REAL FREQUENCIES RELATIONS BETWEEN REAL AND Imaginary COMPONENTS oF MET PAGE 18
14. equalization of individual drivers to achieve flat frequency response Linear acoustic phase for transient perfect image perfect loudspeaker system Precise time alignment of acoustic centres EQ CABS for sensible equalization reduction of most offending room modes Practically unlimited loudspeaker voicing capabilities all in linear phase executed with mathematical precision of a DSP software engine Efficient PWM amplification system Then there is a very important non technical aspect of audio server CD purchases are in massive continual decline these days and for a good reason move to the internet purchased music files started several years ago and is seen as the only way forward Music files can as popular as good improvement from mp3 purchases from iTunes right down to 24bit 96kHz high end music files provided by a number of sources on line It s convenient but not only that You can preview and purchase only the songs you like rather than the whole CD And this is a significant cost saving and Audio Codec ASUS P6X58D E motherboard Socket 1366 which can accommodate 17 960 Extreme Edition Core 17 Processors http www asus com Motherboards P6X58DE _ 1 a sound X Playback Recording Sounds Communications select a playback device below to modify its settings ED Multichannel M Audio Delta 101017 Ready IIITITTLI Spe
15. not be enabled AES INPUT AES AT ie s a vy a L PWM Amplifier Phase Response Ho Response SE mode 90 44 ASTU Ee T p Ep IE n LLL LTTE J so 20 30 m j Ee B 16 jej 2 1 4 e eee E ETT Ts SHH 12 R 500 100k Figure 3 Frequency response in 20 blue green and open load red Top amplitude Bottom phase If the design aim is a minimum phase system then the rolling phase response of the PWM amplifier can be disregarded However in a linear phase system the phase irregularity needs to be compensated for The design strategy for accomplishing such compensation is as follows PWM Amplifier Phase Response Introduce an extra phase roll off which mimics exactly the phase roll off of the PWM amplifier Therefore the inverted HBT method for phase linearization will overcompensate the phase by the exact amount of the extra phase roll off Consequently when the complete chain of devices the loudspeaker crossover PWM amplifier overcompensated inverted HBT phase response is played through the final phase will be a flat line at Odeg Here is an example of the extra device inserted in the tweeter D
16. of 103 137 170 196 226 249 276 work FUNCTIONS k k F XV GRAPHICAL COMPUTATION or RELATIONS BETWEEN REAL AND WARY COMPONENTS OF NETWORK FUNCTIONS 337 Dr Bode s book 2 BX 14 9 page 307 a The above equation is suitable for developing computer algorithm describing phase transter function derived from amplitude frequency response By expressing 19 in terms of amplitude and phase rather than real and imaginary parts JB the phase can actually be derived trom amplitude response F jo FF Where 15 the amplitude response and wis the phase response The above expression can be re arranged as follows In F j9 In A o 72 F jw is analytic and has no zero in the right half plane Now Bodes expression can be applied resulting in In A Car 2 2 a ar a D It s convenient to express amplitude in nepers where 1 8 686 dB Integral is calculated from 0 gt Infinity We need asymptotic slopes towards zero and towards infinity e Passive circuits have easily determined asymptotes Eg 6dB oct HP filter Loudspeaker s asymptotic slopes in SPL are more difficult to determine Integral calculated from 2 octaves below and up to 2 octaves above required bandwidth Hilbert Bode Transform HBT name coined 15 years ago first implemented in SoundEa
17. take exclusive control of this device 9 RE Front Panel Give exclusive mode applications priority 24 Bits 96000 Hz Studio Quality 9 CD Format DVD Format Select the sample rate and bit depth to be used when running in shared DIGITAL mode Restore Defaults Cancel Apply The ASUS Realtek Audio Manager is set to Digital Audio Optical and 24bit 96kHz sampling h M waw 44 1kHz SPDIF with 200ns time base 96kHz SPDIF with 200ns time base The LynxAES16 PCI soundcard Mixer Settings Window w Status Bar Always Driver Optians Level Meter Range Dual Wire In Dual Wire Out Record Dither Buffer Size Advanced Allow Clock Change iF Active w SynchroLock SRC Match Phase SvncStarET w Memory Read Multiple Play 1 Multi channel Mode Steren Mixer Lock Quad 10 12 14 15 Lynx AES16 AES EBU PCI digital soundcard and sound card settings sound AX Playback Recording Seunds Communications Select a playback device below to modify its settings Play 034 04 Lyre AES T6 SRC Ready Play 05 06 Lynx AES 18 SRC Ready Play 07 08 Lynx amp ES16 SRC Ready Play 09 10 Lynx amp ES16 SRC Ready Set Default Properties Configure Speakers Properties General Levels Enhancements Advanced Default Farmat select the sample rate and bit depth t
18. version of the subwoofer has converted the clearly asymmetrical pulse into a much more symmetrical bi polar pulse with post ringing Working UE5 Prototype Summary Comments on the System Advanced linear phase audio system which meets current and future requirements for handling digital music files of any type Windows Media Player Maximum DSP capabilities with LynxAES 16 sound card are 2x8way system and output power for each channel is determined by the PWM ICE amplifier configuration from miniDSP The prototype described here delivered frequency response between 45Hz 21kHz 0 888 using quite average drivers the 2 way stereo loudspeakers And it delivered 16Hz 200Hz 3dB bandwidth for the subwoofers sensible room equalization may be required for your AV room Just to neutralize the most offending room modes that s all you need there The ease of use is guaranteed by the media player functionality Downloading your favourite music files and grouping the files into play lists guarantees that you ll never pay more for your music than absolutely necessary ON Off axis Equalization All subsequent measurements were conducted in room Due to FFT windowing the low end of the frequency response is missing in all plots This is unfortunate as the equalization performs very well in the low end for all polar angles but you ll not be able to see and compare these benefits on subsequent plots U
19. 00 Delay Read 0 ms Output Level wd su Output 10 Pre emphasis Both Channels 00 ms Impulse Response Processing Window Type m MLS Frequency Domain Y Blackmann Harrnis Sym TAA Phase Mike Preamp Post Processing Window Width v Show TENER 7 250 0 Pulse delay 51 ms 125 180 p m T E s GB WB ncm 1 3 PT 120 180 et maj 1 ape 422 520833 __ 115 140 i rud i i i APL Measurement Controls ie A i x x i i Use Saved Buffer 105 100 M Show Phase 100 80 E am Efficiency 900 Calculate SPL 85 60 2222 im a i m aaa 85 20 i 7 Lad SPLSmoothing 16 Lin Fhase 80 0 2224 4 52 75 2 5 505 U Calibration Files p Uselt Use It Import Cal Preamp File B 2 U U x Show Cal Files Feset Cal Files 55 7 7 T a D 50 7 boxed i i i Create Cal Files Export Cal Files 45 1 i I p T 40 35 a i Ee E x U Pen Colours dB Typical Measurement Results UE Technology takes us from a typical level
20. 000 0 Hz Fo 1000 0 Hz 44 Testing assembly PWR ICE Amplifiers pictures Keele Horbach Crossovers htto www linkwitzlab com Horbach Keele20Presentation20Part202 20V4 pdf Application of Linear Phase Digital Crossover Filters to Palr Wise Symmetric Multi Way Loudspeakers Part 2 Control of Beamwidth and Polar Shape D B DON KEELE JR Harman Becker Automotive Systems Martinsville Indiana USA ULRICH arman Consumer Group Morthridge California USA Beamwidih amp DB begs Keele Horbach Crossovers Five Way Array Design Example Desired System Specifications Vertical beamwidth of 5 with side lobes down at least 1 dB Constant beamwidth operating range of 100 Hz on up Height 2 m 6 ft 80 in approximately Use two 15 sub woofers two 8 woofers two 4 lower midranges two 2 upper midranges and a single 1 dome tweeter Beamwidth and Directivity Note Directivity is defined in a half space where an omni directional source has directivity of 1 or a directivity index of O dB Ure 1000 bs DIRECTIVITY INDEX and Qj 20 100 a 10 10 S M go ga 20 100 1k 10k 20k 100 1000 10k 20k Frequency Hz Frequency Hz Directivity Factor Q Keele Horbach Crossovers Crossover Frequency Responses Front Panel Design The chose
21. 412 Ztar 0 0 ohm CD waveguide resonance corrections Dr Geddes designs use a OS Oblate Spheroid waveguide mathematically designed to produce the fewest HOMs High Order Modes possible http www enjoythemusic com diy 0309 gedlee abbey htm Type 2 Way waveguide constant directivity loudspeaker 8 Polyimide compression Drivers 12 inch B amp C 12TBX100 woofer and B amp C DE250 driver Crossover 2nd order passive at aooroximatelv 1200Hz Multiple LCR networks for the tweeter Rz 10 0 ohm C1 2 000 uF 10 000 uF In P E T PT P PT PTT T T T wisa FEST ES ERR EE HEH x gt WE a a a HA htto sound westhost com articles wavequides1 htm intro Peaks around 11kHz and 16kHz can be reduced by series tank circuits Problems with passive crossovers corrective circuits Prevent the amplifier from taking full control of the loudspeaker Crossover DC resistance introduces losses into the circuit and affects driver s Qt Passive crossover requires ideal load resistance to work like an ideal electrical filter driver impedance 1 not Impedance measurements and equalization often necessary Corrections to a bump in driver s SPL affect impedance and phase Drivers parameters heating BL changes
22. 4507 ms Notch Rs 8 78222 ohm Motch Ls 11 4316 mH Equivalent Distance d F 0 10 9484 15 4639 Notch Cs 922 624 uF 5 474 15 5030 Components LI 1 2731 1 7981 1 19 8918 14 0834 2 0 9013 2 28 0957 Typical crossover with corrective circuits Dedicated CAD for loudspeaker design should have these Filter Selector xl 2 Filter Type 1 Filter Configuration L P Passive 6dB oact L P Passive 12dB act L P Passive IsdB act L P Passive 24dB oct H P Passive 3 Filter Litruts High Pass F3dB 1000 Hz Low Pass F3dB 7000 0 Hz Low F ass F3dB Fo for Active Circuits All Pass selected Bessel selected Bullock selected Butterwotrth selected Linkwitz selected Print 4 Passive Heturork Erload 0 ohm x 4 Active Networks Time Delay Seed Components 20000 0 ohm 0 5000 ms 0 03 uF 397 8 Hz ps or k ratio for Notched Ga Crossover Selector x Crossover Configuration 4 Way Passive 6dB oct 2 Crossover Type All Pass selected Hessel selected Bullock selected Butterworth selected Linkwitz selected Way Passive 12dB act Way Passree l8dB act Liw ay Passive 244 3 Passive 6dB oct 3 Crossover Limits First F3dB 30 0 Hz 5 Done Second
23. M MLS Frequency Domain SPL Phase Zin Phase Step Response Mike Compare in Freq Post Processing M MLS Frequency Domain 45deg 60deg What s New in Ultimate Equalizer V6 Implemented CABS hitp von aau dk files 62729248 LF sound field control pdf Also known as ARAM Active Room Absorption Module hiip www neumann kh line com klein hummel globals nsf resources o800aram bda e 517277 rev 231106 pdf File o800ara m bda e 517277 rev 231106 pdf There is also Convention Paper 7262 Multi Source Room Equalization Reducing Room John Vanderkooy e Effectively UE now offers two methods of room equalization that can be used together in minimum phase or linear phase modes CABS and FIR inverted filtering e 16 partition convolution engine for longer IRs therefore better low frequency resolution Should reduce latency in Minimum Phase Mode The original 8 partition option still available for the lowest latency Long Channel Delays 0 168ms delays his feature allows for adding long delays to each channel for creating special echo effects in QUADRO or other configuration 7 1 HT system configuration available Also 2 BBM and 7 4HT BBM CABS systems available Up to 1 47Hz low frequency resolution Supports 16 channel LynxAES16 digital sound card and Delta1010LT analogue sound card e Runs Windows audio engine in WASAPI Exclusive Mode
24. SP processing path og Gain 0 0 dB PWM Amplifier Phase Response 20 dB deg 5 6 8 10 20 30 40 50 80 100 200 300 400 1k 2k 3k 4k Bk 8k 10k 20k 30k 40 60k 80k Hz PWM Amplifier Phase ResponsePWM Amplifier Phase Response 2 Ultimate Equalizer Frequency Domain 8 Outputs DER 3 Ultimate Equalizer Frequency Domain 8 Outputs Fitter 1 HBT phase correction curve E 30 AGA A with before inversion LA e amplifier included 200 300 400 500 20k 30k 40k Hz 30 40 50 80 100 200 300 400 00 20k 30k 40k Hz HBT phase response without and HBT phase response with the extra phase roll off PWM Amplifier Phase Response 500kHz PWM amplifier switching component still being present on the output e Without additional filtering there may be up to 3Vpp of 500kHz present in the output Simple LC lo pass filter with 25 coil and 150nF capacitor will improve suppression of the carrier significantly This additional filter will increase phase shift at 20kHz beyond the specified value and again may need to be taken into account for linear phase designs The effect of this additional filter also needs to be compensated in the Ultimate Equalizer More information on PWM output filtering can be found in http www ti com lit an sloa023 sloa023 pdf http pdfserv maximintegrated com en an AN624 pdf Vp pC2225 31 Trigger 1 2 Ext Bottom 500kHz component before filter Bottom 1kHz tone 500kHz com
25. Ultimate Equalizer DSP Loudspeaker Management System April 14 2014 Bohdan Raczynski AES Associate Member Bodzio Software Pty Ltd Melbourne Australia Email bohdan bodziosoftware com au Web http www bodziosoftware com au Contents at a Glance Equalizer Motivation Frequency Response Corrective Circuits Impedance Correcting Circuits Corrective Circuits used in CD Constant Directivity waveguide designs Problems with passive corrective circuits Foundations of Amplitude Phase Relationship Loudspeaker EQ Process in Details Amplitude Equalizer Design Inverting System Phase Equalization Strategies Hoom Equalization Identifying Minimum phase Regions opatial Averaging Equalization Threshold Equalization Strategies Example of UE Systems 5 2 HT System with Analogue Amplifiers System Evolution Path 24bit 96kHz AES EBU Audio Server with DSP Loudspeaker Management System Typical Performance in Frequency and Time Domain ON Off axis Equalization What s New in V6 Screen Examples and Amplifier Builds Keele Horbach Crossover Summary Typical contemporary crossover with corrective circuits 3 Way 12dB oct Zobel L pad SPL Notch Zin Notch In 3 602 mH R1 100 0 uahm Fi4 6 6 ohm C2 28 125 uF Ca 45 000 uF I 2 I 4 4 5 8 m m m CB 46 216 ips ond oka Lo mom esa 51182448 mH R18 6 7 ohm T F8 100 0 uchm 7 7 Ae
26. akers Realtek High Definition amp udia fe Mot plugged in mi a Realtek Audio 2nd output Realtek High Definition Audio Not plugged in Realtek Digital Output Realtek High Definition Audio Ready Digital High Definition Audio JA Default Device T setDerault Properties Realtek Digital Output Optical Properties Cancel Apply General Supported Formats Levels Enhancements Advanced Encoded formats Which of the following formats is your Digital Receiver able to decode 0 DTS Audio Microsoft Test Dolby Digital I Motherboard SPDIF output is looped TE back to LynxAES16 Digital Input 1 Which of the following sample rates are supported by your Digital Receiver C 44 1 kHz 96 0 kHz e Test 48 0 J 132 0 kHz and Audio Codec Realtek Digital Output Optical Properties lt Realtek HD Audio Manager j General Supported Formats Levels Enhancements Advanced Device advanced Bc Digital Output settings Default Format Select the sample rate and bit depth to be used when running RGG in shared mode Set Default M Device Back Panel 2 channel 24 bit 36000 Hz Studio Quality Sound Effects Default Format 9 9 Exclusive Mode Allow applications to
27. and Im Here are several examples of how the complex conjugate is used in DSP If x n has a Fourier transform of then x n has a Fourier transform of X In words flipping the time domain left for right corresponds to changing the sign of the phase another example recall from Chapter 7 that correlation can be performed as a convolution This is done by flipping one of the signals left for right In mathematical form a n b n is convolution while a n b n is correlation In the frequency domain these operations correspond to A f x B and A f B respectively As the last example consider an arbitrary signal x n and its frequency spectrum A f The frequency spectrum can be changed to zero phase by multiplying it by its complex conjugate that is X x Y f In words whatever phase KE aya GII te GRANAT TY sim its opposite remember when frequency spectra are multiplied their phases are added In the time domain this means that x n x n a signal convolved with left right flipped version of itself will have left right symmetry around sample zero regardless of what x n is Inverting System Phase Caution use FIR Onginal System Equalized System Frequency Response jab jba b la b j je lg 5 Fe Im j0 O Im Magnitude Re Im b Magnitude JRE Im la eB Pen b Im
28. e BBM Binaural Bass Management AES Preprint 6628 for enhanced bass management Room Equalization Complex problem with many issues involved High performance loudspeakers first arrival flat within 100Hz 10kHz in room Need room friendly constant directivity loudspeakers Loudspeaker in room excite room modes modes influence the character of the sound At mid and high frequencies modal density is high mods overlap room response diffuse At low frequencies modal density is low The room imprints it s own characteristics on the sound quite profoundly lt 200 2 Summation of direct and reflected sound will produce amplitude variations at the listening location that can span 30 40dB in magnitude non minimum phase The lower frequency of the sound wave the more minimum phase characteristics will be exhibited by the room Steps Towards Improvement Follows Ph D Floyd E Toole paper http www harmanaudio com all about audio acoustical design pdf First start with a good room Secondly use good speaker smooth extended bass response Thirdly employ a DSP to put the icing on the cake Desirable to have some form of a detector that would indicate frequency range s where the room is definitely exhibiting minimum phase characteristics Application of a minimum phase DSP process to control room modes inevitably results in injecting less energy into the room within the correction frequency range Re
29. f sine waves each contributing it s required amplitude and phase It is due to this very feature that when passed through an audio system the square wave can reveal time domain performance Issues of the system This Is because all of its sine wave components must be passed by the system without time distortion or different delays in order to recombine as a square wave at the output of the system under test Real life loudspeaker example Measured system s magnitude red and phase green MLS impulse Response Ref 57 37 In 0 18 Bin 78 Scroll O 752 t3 MLS Measurements Control MLS Quick SPL SPL ZIN CSD ALC 14 MLS Signal Generator MLS Length Cycles IR Smoothing afi IMP 1 1638 m Sampling Rate uto Delay Read 48000 500 ms Use Saved Buffer Output 2 30 Save Input Buffer lt gt Ptre emphasis Both Channels 00 ms IR Processing Window Type Zoom Blackmann H arris Ax mpl 5 1xTime Window Width Show 144000 Pulse delay 0 0 ms 300000 Time ms Export IR ClearIR SPL Measurement Impedance Clear SPL Zin Calibrate Cal 0 993701 IR gt SPL Show Ph Add 10 0 dB ToSPL Run MLS SPL Smoothing 112 IR gt Zin Calibration Files Export Zin Uselt Mike File peg Uselt Cal Preamp File Target System Show Cal Files Print Export SP Matched Filter Active CAD
30. ity Complies with http www aes org technical documents AES TD 1001 pdf Realization involves only basic mechanical assembly with plug and play components and can be easily accomplished by a DIY enthusiast McCauley 18 6174 subwoofer 2 way Left 2 way Right McCauley 18 6174 subwoofer a e Audio Server DSP Loudspeaker Management 1 System 516 soundcard ul ES je z k Wireless 3 x AES EBU digital links SEES mini keyboard 24bit 96kHz AES EBU Audio Server with DSP Loudspeaker Management System 0 2 Subwoofer system pam AES Subwoofer Left with Subwoofer right with PWRE ICE 125 AES EBU PWR ICE 125 AES EBU amplifier amplifier McCauley 6174 drivers in 300 litre vented 20Hz tuning boxes with PWR ICE 125 AES EBU PWM amplifier in each box Left Right Loudspeakers AES EBU links to Two way right loudspeaker with PWR CE 125 amplifier Two way left loudspeaker with PWR ICE 125 amplifier 2x8 woofer drivers 1 tweeter driver with PWR ICE 125 AES EBU PWM amplifier in each 50 litre vented box tuned to 45Hz Some of the characteristics of the system 24bit 96kHz studio quality processing system Active system allows amplifiers to exert maximum control over loudspeaker driver and makes crossover characteristics independent of driver loading AES EBU or SPDIF links between all system components HBT
31. ltimate Equalizer Frequency Domain 8 Outputs Driwer 2 SBE ATE HBT 2 SBL m Front Left x EEG deg 10 20 30 40 80100 ak 4k Sk zUk 30k 2 ON Off axis Equalization MLS Frequency Domain SPL Phase Mike Preamp Post Processing 125 120 115 110 105 100 85 30 85 80 75 70 55 50 55 50 45 40 35 dB 180 160 140 120 100 80 60 40 20 0 20 40 50 80 20 30 40 50 80 100 30k 40k Hz 48kHz sampling 1m On axis MLS Frequency Domain 10 00 dB Phase 0 00 deg Freq 35562 3 Hz SPL Phase Zin Phase Step Response Mike Preamp RLC Compare in Freq Post Processing MLS Frequency Domain SPL Phase Zin Phase Step Response Mike Preamp RLC Compare in Freq Post Processing MLS Frequency Domain SPL Phase Zin Phase Step Response Mike Preamp RLC Compare in Freq Post Processing 15deg Vertical WTW loudspeaker with HBT equalization to 30000Hz M MLS Frequency Domain SPL Phase Phase Step Response Mike RLC Compare in Freq Post Processing MLS Frequency Domain MLS Frequency Domain SPL Phase Zin Phase Step Response Mike Preamp RLC Compare in Freq Post Processing 50cm 100cm 210cm WTW loudspeaker with equalization to 30000Hz lil MLS Frequency Domain
32. n room centre opatial averaging Equalization Threshold black curve 125 120 115 180 180 140 e B recess Gr Del Being guided by the excess group delay graph we should avoid equalizing the room response around 40Hz and 170Hz SPL below black curve will not be equalized Room Equalization Transfer Function Ultimate Equalizer Frequency Domain 16 Outputs alk 4Dk Hz Hoom Equalizer s complete Minimum Phase brown curve and Linear Phase blue curve transfer function Summary of Room Equalizer function Room Equalizer Ampl 90 00 dB Phase 0 00 deg Freg 11 2 Hz Measurement Control Window Width Reference IR Location 1 O _ 89995 20 Measured Location 2 A uU B 5 Win Time ms Qu LE M ed anes a Ta 1874 90 HM MURAL HOME TART SA Location 4 IBI Add dB To SPL i 95000069 kasamaan 90056980 gu a x 90900209 c COcOO0 bODODOdO 09000085 booocoon x GDA paanuman D 5 oO oo 114 Location 6 IB eedem nennen nnnm PO O sasa 0 0000 AE
33. n 75 vertical beamwidth and the lobe requirement dictates a critical driver spacing of about 0 55 wavelength SPL dB Keele Keele HP H LF 1ZdB act LF 185dB act LP H Complete Keele Horbach Crossover in UE gt Keele TWE E eqQuericy 4 Element cut aff center fr Circuit and Shelvin 1000 0 Hz 10000000 QR 0 000000 This Element Do SUITE 164 8 6 ohm 123 46 000 uF C2 38 125 uF 1 23 24 920 uF K La 192 0 uH 100 uohm R25 2 Zohm 28 5 9 ohm 26 93 235 DER Hessel LP GdB oct Fr 1000 0 Hz Fo 1000 0 Hz Fa 1000 D Hz Fa 1000 0 Hz I b File Loaded b File Loaded Ta Blot x Hz Ta Plat Front Left Front Right Summary UE Technology takes us from a typical level of drivers performance L Driver Transfer Function Driver Transfer Function 60 80 100 200 3k 4k Bk 8k 10k 20k SPL phase measurements of woofer and tweeter in a 2 way system to this level of performance MLS Frequency Domain SPL Phase Mike Preamp Post Processing 180 160 140 120 400 30k 40k Hz 1 120 115 110 105 100 g5 25 an FE EG 55 o0 45 40 3n 120 115 119 105 100 ZE ao a r5 65 60 45 40 3n dE
34. n Freq Post Processing Copy Master E Indexing Scheme File 1 j 38v HB Transform HP stop 52 0 Roll off 400 LP start 100000 Rol off 1320 Delay 00 Copy Master Fen Colours Measurements conducted in noisy environment SPL red Phase green VERY noisy Noise more persistent in low frequency range 50Hz Cone break up visible above 8kHz Hilbert Bode Transform Phase from SPL on RS28F 4 tweeter ini xi ia PS SE Sm ZA H RA CR DOST EN TE oe age Sey pags es MM en pa a es AEAEE EAER TEA 7 ru yituyuyuyi EPE PEEP pe a E a E ut tI cere dB deg 10 20 50 80 100 200 300 400 500 26 3k 4k Bk 20k Measurement is FF T windowed to avoid room reflections Low frequency roll off is 12dB oct sealed box Hilbert Bode Transform Phase from Zin DIN w a sia KW KIC CO KIC CO Y RC hl hh Oi Gi
35. o be used when running in shared made 24 bit 96000 Hz Studio Quality be Test Exclusive Allow applications ta take exclusive control of this device Give exclusive mode applications priority Restore Defaults The LynxAES16 PCI soundcard e Does it work OK when Windows Media Player is active hopefully yes e he following information should be displayed by the Lynx Mixer Please note that Preferred Clock Source is selected as Digital In 1 this is where we connected the motherboard audio link The Rate Select is set to 96kHz Lynx AES16 Mixer Adapter xi Sample Lock Validity Parity CSCRC Emphasis Rate Clock Rate Curent i tal th Current Rate 96 0 kHz 0 kHz Digital In zl nicked l 6221 125 Not Present Rate Select 96000 Digital In 3 Unlocked Mot Present Rate Lock m Digital In 4 Unlocked Nat Present Enable SRC Ratio SynchroLock Digital In 5 Unlecked Net Present sRcOl Jos Digital In 6 Unlocked Not Present Ske Orr Preferred Clock Source Digital In 7 feted UE Internal inode PO ju ji s External Mot Present P Digital Out 1 v vali CERES Header Not Present dies us Emphasis Digital Out 2 valid Emphasis
36. of driver s performance L Driver Transfer Function Driver Transfer Function 60 80 100 200 3k 4k Bk 8k 10k 20k SPL phase measurements of woofer and tweeter in a 2 way system to this level of performance MLS Frequency Domain SPL Phase Mike Preamp Post Processin 50 100 400 30k 40k Hz 1 120 115 110 105 100 g5 25 an FE EG 55 o0 45 40 3n 120 115 119 105 100 ZE ao a r5 65 60 45 40 3n dE Typical Subwoofer Measurement Results HBT Editor Window Amplitude 71 78 dB Freg 10 0 Hz Bin O 160 mn x See eee ee kj 140 s 2 2 120 sa x ee oh NEO E 100 RRS Ht en ZE ac Had a Bn i 1 eim M 1 Ld s LE 420 lal AA Lo LR LLL fe 460 AK W AE A 1 TLI z z H z z z z z z z z z z z z z z deg 10 20 30 40 an 100 200 300 400 Tk 2k 100 120 140 160 1 ELI 5 5 5 5 5 5 B deg 10 20 30 40 eo 100 200 300 400 600 1k Typical Time Domain Measurements KCN BLOW 1400 mG 4 0c imer Vernier Probe mas wd 20Hz square wave Minimum Phase Mode and oms Impulse in Minimum Phase Mode and Linear Phase Mode minimum phase
37. ponent Top after filter 1V div before filter Top after filter 10V div Loudspeaker Management System UE6 DSP engine Large selection of filter configurations and types and the ability to cascade them any way you like Cascade other filtering elements like notches shelving and peaking elements with adjustable Q factor Each one of these long chains can be applied as a filtering channel for individual driver in the enclosure In order to visualize the whole crossover you would simply pick filtering elements from the available tray of components and then place and link them on the screen to effectively built the whole crossover as a block diagram with interconnected filtering elements system Configuration je Hen Ne Hessel Bessel _ LP SdB ct LP GdBvoct 2 arie Loaded Fo 1000 0 Hz Fa 1000 0 Hz Hessel Bessel Hessel LP 6dB oct LP GdB oct a 1 Fo 1000 0 Hz Fo 1000 0 Hz b File Loaded BdB oct File onde GE Ta Plat o 1000 Tik To Plot Loudspeaker Management System UE6 DSP engine The tray is shown to the right To keep things simple there are only three active elements using which you can built the entire crossover and room EQ Schematic pick and place component tray or use one of 17 pre set configurations 2 Ultimate Equalizer Frequency Domain 16 Outputs ini x 20 180 15 160 10 140 5 120 0 10 eae ZEE 5 80 Mmm st
38. r 2 812 uF COST RIS 6 3 ohm C17 6 980 uF UB C14 302 669 uF TO 5 10 11 mil 10 11 112 C23 24 820 uF 19 13 12 15 C20 2 812 ure 94538 uH 7 192 0 uH 830 6 2 ohm R22 100 0 uohm R25 22 ohm R28 5 3 ohm CZA 1204 uF C38 93 235 14 16 17 15 14 16 17 18 Good quality inductors low Rloss High power low inductance resistors High voltage bi polar capacitors Inductors mutual orientation important de coupling Typical crossover with corrective circuits L Pad Zobel Network Amplitude Peak EQ Amplitude Peak Equaliser L Pad Calculator 629 Zobel Calculator Design Parameters Design Parameters _ 8 00 ohm Re 8 00 ohm Re 8 00 ohm _ Calculate Is x 3 00 dB Le 1 50 j _ Rel 65 00 ohm Fh 40000 Hz Rp 19 3921 ohm ALh 1 00 dB L Pad Rs 2 33643 ohm Rz 8 38451 ohm Zobel Cz 18 5819 uF Design Parameters Tank Hp 3 30030 ohm TankLp 0 23357 mH Tank Cp 27 1044 uF Lattice Metwork Calculator Design Parameters Impedance Peak Equaliser 7 Design Parameters Rload 8 00 ohm TET 9 Fo 10000 Hz a Fe 0 708 2 nd Order 4 50 10 44 Calculated First Order Second Order Delays 18 00 ohm 0 0 3183 0 4495 ms T F Fa 0 1531 0
39. solution of 1 is not sufficient 1 100ct 1 200ct is recommended Low frequency active absorber will reduce the SPL at modal frequencies but for users favouring modal gain it may also create a perception of lacking decay at those frequencies It s like well where has the bass gone oome researchers suggest that equalization that results in notches deeper than should be applied with caution as this would reduce node s original RT60 by half Room reverberation below 0 3s results in unusually dead acoustics As always extensive listening tests are the best criteria Implementation of the Room EQ Room equalization strategy What are the frequencies where we can deploy the equalizer What are the locations where the sound is expected to be improved and How much equalization we should provide The first step in approaching room equalization process is identification of the minimum phase regions A minimum phase system is one which is able to transfer input energy to its output in the least amount of time for a given frequency response Then system s response can be inverted by minimum phase EQ If we have a system such as this then we can create an Inverse filter which in combination with the system s transfer function would produce a flat frequency response and correct the phase response as well This is quite simplified view but sufficient for our purpose So the minimum phase property of the room would qualif
40. sy The frequency range of interest is split into three ranges and contribution from each range added during final assembly of the phase response LF tail HF tail and range of interest User of the algorithm can visually inspect the loudspeaker frequency response and determine the asymptotic roll off order on both frequency extremes Frequently the loudspeaker in question has the roll off determined by design For example the final low frequency roll off of a sealed enclosure is 12dB per octave and 24dB per octave for vented enclosure Another one is QB3 18dB oct In a typical implementation the transform is driven by 4 editable parameters and they should be selected to obtain the best match for phase and amplitude between measured signal and calculated transform over the widest frequency range Typically good match can be obtained way beyond driver s operating frequency range A minimum phase system is one which is able to transfer input energy to its output in the least amount of time for a given frequency response Hilbert Bode Transform Phase from SPL 12 guitar speaker QB3 vented alignment Execute Above gt Maste Show Master Buffer show Phase Difference MegB 4 Add 0 00 tt Add 0 00 di Add LE MLS Frequency Domain F Jay Soundeasy Mici Cal File With Phase Correction txt SPL PH GD Zin Phase Step Response Mike Preamp RLC Compare i
41. tional to distance between front and rear subwoofers mee Rear Left Bass Sink Rear Right Bass Sink Listening to music being played instead of a single frequency clearly shows that with CABS the booming bass is removed in the source room and clearly reduced in the neighbour rooms Controlled Acoustic Bass System CABS Nielsen s results Kelin Hummel in 0800 Subwoofer User Manual ARAM Active Room Absorption Module Figure 2 Simulation of 44Hz in room A Left CABS off 0 2 0 Right CABS on 0 2 2 The bass coverage is much more even throughout the room with the addition of a second subwoofer in the front of the room However the troublesome resonance is not yet suppressed x d ka aiw sd T T T 1 Figure 3 Measurements 11 Room A at 25 positions Left CABS off 0 2 0 Right CABS on 02 2 Figure 4 Measured cumulative spectral decay in room A in one point The addition of the ARAM subwoofer in the rear of the Left CABS off 020 Right CABS on 0 2 2 room produces an even distribution of bass across the room and over a wide frequency range Room EQ Strategies Do not equalize frequency response at all just use UE as an active DSP crossover with HBI equalizer and get full benefits of an active system Use built in peak notch shelving filters to provide broad equalization Up
42. to 32 CAD elements can be used in each loudspeaker system Even complex room EQ can be created this way Equalize at single point Perform multiple measurements at up to 6 locations and use the average to equalize Perform minimum phase equalization or linear phase equalization Use CABS approach to sink bass energy at the back of room Use both RoomEQ CABS Examples of UE Systems 24bit 48kHz 5 2HT Audio Server with Analogue Amplifiers McCauley 18 6174 subwoofer 2 way Front Right McCauley 18 6174 subwoofer 2 way Front Left 2x200W Subwoofer amplifier 3x 100W Fx50W surround amplifier Up to 10m distance 2 way Rear Right 2 4GHz Wireless Keyboard 2 Rear Left working as Remote Control Centre Speaker Examples of UE Systems 24bit 48kHz 5 2HT Audio Server with Analogue Amplifiers I AM k qas T 6 4 Subwoofer performance Rear Loudspeaker performance m 4 m m m FH EH um FT Front loudspeaker performance Centre loudspeaker performance Evolution of the UE Systems 24bit 96kHz Digital Systems 2 4 5 Evolution of the UE Systems 24bit 96kHz Hybrid Analogue Digital Systems 7 2 7 4 BBM CABS 24bit 96kHz AES EBU Audio Server with DSP Loudspeaker Management System oystem presented here is a complete audio playback system of studio qual
43. y the usage of our room equalizer Identifying Minimum phase regions e Looking at the measured amplitude and phase responses of the loudspeaker in the room alone it is not possible to determine the minimum phase regions Identifying Minimum phase regions Examining the flatness of group delay would bring us a step closer to determining the minimum phase regions but still no good Excess group delay we were able to create a system that has the same frequency response as the measured one but is definitely a minimum phase type we could then create a differential phase response by subtracting phase response of such system from the measured phase response Now if the measured system was a minimum phase type then the excess group delay based on differential phase response would be a flat line Conversely any deviation of the excess group delay from a flat would indicate that this frequency range is the non minimum phase type Thus we have just laid down the principles of our minimum phase detector The minimum phase system is created by taking a HBT of the measured frequency response The HBT will output a minimum phase phase of the measured system We will then use this phase response in our calculations of the excess group delay Identifying Minimum phase regions PN 75 20 70 40 65 60 80 55 100 10 0 30 40 60 80 100 200 Calculated Excess Group Delay of loudspeaker in single locatio
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