Index
Page numbers in italics indicate figures and in bold indicate tables on the corresponding pages.
1-bandpass notch filters 337
1.0 dB-Chebyshev crossovers see Chebyshev crossovers
1 dB-Chebyshev filters 162, 163–165
3 dB-Chebyshev lowpass filters 162, 165–167
3-way crossovers 70
6 dB/octave dipole equalisation 388
±15 V supply designing 616–619, 617–618,
±17 V supply designing 619, 619–620
5532 low-noise unity-gain balanced input stage 597
5532 opamps 623; common-mode distortion 474–477; distortion in shunt-feedback mode 478; internal circuitry 471–572; output loading in shunt-feedback mode 472–474; output stage biasing 477–482; series feedback 472–474, 476, 575; with shunt feedback 471–572, 472; versions 482
Acoustical Engineering 35
active crossover design 584; balanced line input stage 627–628; balanced outputs 638; bandwidth definition filter 628; capacitor selection 627; crossover programming 638–639; design principles 625; gain structure 626–627; HF signal path 628–632, 629, 630, 632, 633; level trim controls 636–638; output attenuators 636–638; resistor selection 627; specification 625–626, 626
active crossover design, LF path: 400 Hz Linkwitz-Riley lowpass filter 635; no time-delay compensation 636
active crossover design noise analysis: HF path 640–641; input circuitry 639–640; LF path 642
active crossover design noise performance: input circuitry 643–646; power amplifier noise 646–647
active crossovers 5–6; advantages and disadvantages of 9–15; bi-amping and bi-wiring 6–8, 7; multi-way connectors 22–23; as next step in hi-fi 16; popularising 21–22; system configurations 16–20, 16–20
active filters 145–146, 425; distortion in 297–298; noise in 327–328
active servo technology (AST) 548
AD797 599
AD797 opamps 492–494; common-mode distortion 494; series-feedback THD 495
AD797 voltage-follower 494
adjustable peak/dip equalisers 398–404, 398–405
air, sound absorption in 44–46, 45–46
air-motion transformers 31
Akerberg-Mossberg highpass filter 279–280, 280
Akerberg-Mossberg lowpass filter 276–279, 277–279
allpass filters 147; 1st order 356–364, 357–363; 2nd order 364–369, 365–368; 3rd order 369–373, 369–373; cascaded 1st order 363, 363–364; distortion and noise in 1st order 362, 362–363; distortion and noise in 2nd order 368, 368–369; distortion and noise in 3rd order 370–373, 371–373; in general 355–356, 356; higher order 373–379, 374–379, 376; Tow-Thomas biquad notch and 285–286, 286
all-pole crossovers 61; see also types, crossover
all-stop filters 147
amplifiers, multiple differential 596
amplitude/frequency distribution 507–510
amplitude peaking and Q in filters 150–151, 152
arbitrary capacitance values capacitors 446–447
arbitrary resistance values resistors 438–439
asymmetric crossovers 62
Atlantic City Convention Hall 33
attenuation, lowpass filters with 236, 236–237
attenuator 504
audio spectrum 518
automotive audio and active crossovers 5
automotive audio subwoofers 540–541
auxiliary bass radiators (ABR) 527, 528, 532; loudspeakers 28
Baekgaard, Erik 111
Baggen, Harry 132
Bainter notch filter 337–342, 340, 342
balanced cables and interference 560–562
balanced circuit 593
balanced inputs 559; amplifiers 556; stage, variations on 576
balanced interconnections 559, 559–560,
balanced signal levels 563
bandpass filters 146; 1-bandpass notch filter 337; high-Q 334–335, 335; multiple-feedback 333–334, 334; Tow-Thomas 280–285, 281–283, 284–285
bandwidth and noise 328–329, 328–329
bandwidth definition filters 628; highpass 262–267, 262–267; lowpass 237
basic electronic balanced input 565–567, 566, 566
bass management facilities 535
bass response equalisation 388–389
Baxandall configuration 540
Bernoulli, Daniel 155
Bessel, Wilhelm 155
Bessel crossovers: 2nd order 79–80, 79–80, 149; 3rd order 89, 90–91; 4th order 99, 99; cutoff frequencies 148
Bessel filters 148, 155, 158–160, 158–160; bandwidth definition 237–238, 237–239, 238; linear-phase 182–183; with non-equal resistors 224, 225; for time delays 382–383, 382–383; transitional 182; up to 8th order 173–174, 174, 174
bipolar-input opamps 463
bipolar junction transistor (BJT) opamps 460, 467
biquad equalisers 407–413, 408–409, 411–413; capacitance multiplication for 414, 414–415
biquad filters 276; Akerberg-Mossberg 276–280, 277–280; Tow-Thomas 280–288, 281–283, 284–285, 286, 287
Boctor notch filters 343–344, 344
Boltzmann’s constant 441
brickwall filters 147
bridged-differentiator notch filter 342, 343
bridged-T equalisers 406–407, 406–407
Butterworth crossovers: 2nd order 71–78, 72–77, 133–134, 134–135, 149; 3rd order 84–86, 84–86, 135, 136; 4th order 93–95, 94–95, 135, 136–137, 137; cutoff frequencies 148; subtractive 133–134, 134–135, 135, 136, 136–137, 137; transitional 182; up to 8th order 168, 168–172, 169, 170–171
Butterworth filters 149, 151, 153, 153–155, 207; 3rd order 248, 248, 248–249; 4th order 215–219, 249–252, 250, 251–254, 252; 5th order 229, 229, 229–230, 257–258, 259, 259; 6th order 232–234, 233, 233–234; bandwidth and noise in 328–329, 328–329; bandwidth definition 237–238, 237–239, 238, 262–267, 262–267; defined gains 245, 245–246, 246; distortion aggravation factor 298–302, 299–300, 300–302; equal resistors 244, 244–245; Legendre-Papoulis 187–189, 188–189, 189; with non-equal resistors 224, 225; with other filter characteristics 256, 257, 258; single stage 217–219, 218–220, 220, 232–234, 233, 233–234, 250, 252–253, 253, 253–254; two stages 251–252, 252, 252, 259, 260, 260
C2, DC-blocking capacitor 558
Cambridge Audio 840 W power amplifier 598
capacitance multiplication for biquad equalisers 414, 414–415
capacitor-coupled power amplifiers 522
capacitors: arbitrary capacitance values 446–447; in audio circuitry 448; distortion and 320, 320–321; electrolytic capacitor non-linearity 454–457; non-electrolytic capacitor non-linearity 449–453; non-linearity 448; shortcomings 447–449; values and tolerances 445–446
carbon composition resistors 436
carbon film resistors 426, 443
cardioid subwoofer arrays 539
cascaded 1st order allpass filters 363, 363–364
Cauer filters 179–181, 180–181
CBT (constant beamwidth transducer) line arrays 39
ceramic capacitors 449
characteristic frequencies 148
Chebyshev, Pafnuty Lvovich 160
Chebyshev crossovers: 2nd order 80–81, 81–82, 149; 3rd order 89, 91–92, 92, 93; 4th order 99–101, 100–101
Chebyshev filters 160–162, 161–167; 4th order 216–217; inverse 177–178, 178–179; linear-phase 183; with other filter characteristics 256, 257, 258; transitional 182; up to 8th order 175–176, 175–176
chip surface-mount (SM) resistors 427
circuit noise and low-impedance design 504
clip-detect indicators 501
clipping 10
combined HF-boost and HF-cut equalisers 398
combined unbalanced and balanced inputs 576–577
common impedance coupling 562
common-mode distortion, opamps 467–468
common-mode input impedances 567
common-mode range, opamps 463
common-mode rejection ratio (CMRR) 507, 559, 563–565, 564; amplifier component mismatches 571, 571–573, 573, 574; opamp 570; opamp frequency response 569–570, 570, 570; opamp gain 568, 569–570, 569; theoretical balanced interconnection 564
common-mode signals 567
component sensitivity in filter design 195–196, 196, 202, 206, 206–207
component series tables E3 to E96 659–660
cone break-up 2
conjugate impedance compensation 12
constant-power crossovers 62–63
constant-voltage crossovers 63
control protection, system design 500–501
coupling 448
crossover design references 649–652, 655
crossover frequency control (lowpass filter) 534
crossover in/out switch 534
crossover output stages 604
crossovers: absolute phase 57–58; active (see active crossovers); beaming and lobing and 2–3, 3; bi-amping and bi-wiring with 6–8, 7; design references 649–652; function of 1; linear phase 56–57; matching loudspeakers and 20–21; minimum phase 57; necessity of 1–2; notch (see notch crossovers); passive 4, 4, 9–10; phase perception 58–59; requirements (see requirements, crossover); subjectivism and 23; subtractive (see subtractive crossovers); target functions 59–60; topology 113–118, 114–118; types (see types, crossover); US patents 653–654
damping factor 533
D’Appolito configuration 33–34
data-acquisition application 583
DC-blocking capacitors 558, 575
DC-offset protection circuitry 522
decoupling capacitors 448, 618
defined gains: 2nd order Butterworth highpass 245, 245–246, 246; 2nd order Butterworth lowpass 207, 208, 208
delay lines for subtractive crossovers 379–381, 380–381
delays 10
design, filter 271, 272; 1st order highpass 241, 241–242; 1st order lowpass 197; 2nd order highpass 242–247; 2nd order lowpass 198–209; 3rd order highpass 248, 248, 248–249; 3rd order lowpass 209–215; 4th order highpass 251–256, 252–253, 252; 4th order lowpass 214–224, 225; 5th order highpass 252–253, 257–258, 259, 259; 5th order lowpass 225–232; Bainter notch 339–342, 340, 342; component sensitivity in 195–196, 196; defined gains 207, 208, 208, 245, 245–246, 246; equal capacitor 204, 204–206, 205; equal resistors 244, 244–245; filter frequency scaling 202–204; multiple-feedback 272–275, 276; non-equal capacitors 247; non-equal resistors 207, 209, 214–215, 215; optimisation 209; real 195; unity gain 199, 199–202, 201, 243–244; variable-frequency 239, 239–240, 267–270, 268–269; see also filters; single stage filters; three stages highpass filters; three stages lowpass filters; two stage filters
dielectric absorption 447–448, 448
diffraction compensation equalisation 389–390, 390
DIN connectors 22
dip equalisers with high Q 402–404, 402–405
discrete-opamp hybrid stage 594
discrete transistor technology 503
distortion: in active filters 297–298; aggravation factor 297, 298–302, 299–300, 300–302, 321, 321–322; capacitors and 320, 320–321; Doppler 48; drive unit 47–48; and looking for DAF 303–304, 303–305; mixed capacitors in low-distortion 2nd order filters 310, 310–311; modulation 46–47; in multiple-feedback filters 321, 321–323, 322–323; in 2nd order highpass filters 308–310, 309; in 2nd order lowpass filters 305–307, 306–308; negligible extra 55–56; and noise in 2nd order allpass filters 368, 368–369; and noise in 3rd order allpass filters 370–373, 371–373; and noise in 1st order allpass filters 362, 362–363; in 3rd order lowpass single stage filters 311–312, 311–312; simulations 318–320, 319; in 4th order highpass single stage filters 317–318, 318; in 4th order lowpass single stage filters 314–317, 315–317; in Tow-Thomas filters 324–327, 325–327
distortion aggravation factor (DAF) 297, 298–302, 299–300, 300–302; looking for 303–304, 303–305; in multiple-feedback filters 321, 321–322
distributed peak detection 520–522
domestic electronic crossover standard 506
Doppler distortion 48
drive unit equalisation 387–388
dual opamp 599
dual-opamp 5532 460
dual-opamp TL072 460, 469–470,
dual supplies from a single winding 622, 622–623
Duddell, William 31
Duelund crossover 113
E96 resistor 429
electrical noise 432
electrolytic capacitors 446; distortion 454, 455; non-linearity 454–457
electrolytic coupling capacitors 604
electrolytic-sized decoupling capacitors 615–616
electromagnetic planar loudspeakers 30–31
electronic crossover 520; mode switching in 502
Electronics World 121, 132, 655–656
electronic vs transformer balanced inputs 563
electrostatic coupling 561–562
electrostatic interference 468
electrostatic loudspeakers 29–30
Elektor 132
elliptical filter crossovers 121–125, 122–124
elliptical filters 179–181, 180–181; using Bainter highpass notch 342
equal capacitor, Sallen & Key 2nd order lowpass 204, 204–206, 205
equalisation: by adjusting all filter parameters 422; bass response 388–389; with -3 dB/octave slopes 415–419, 416–418; with -4.5 dB/octave slopes 420, 421; with -3 dB/octave slopes over limited range 419–420, 419–420; diffraction compensation 389–390, 390; drive unit 387–388; by filter frequency offset 421–422; loudspeaker 387–393; need for 385; with non-standard slopes 415–421, 416–421; outcomes of 386, 386–387; room interaction correction 390–393, 392; 6 dB/octave dipole 388
equalisation circuitry 393, 505; biquad 407–415, 408–409, 411–414; bridged-T 406–407, 406–407; combined HF-boost and HF-cut 398; dip equalisers with high Q 402–404, 402–405; fixed frequency and low Q 398–399, 398–400; HF-boost and LF-cut 393–395, 393–395; HF-cut and LF-boost 395–398, 396–397; parametric 405, 405–406; variable centre frequency and low Q 400–402, 401
equal resistors, Sallen & Key 2nd order highpass 244, 244–245
equivalent input noise (EIN) 584
equivalent series inductance (ESL) 447
equivalent series resistance (ESR) 447,
external noise 560
external signal levels 555
Fairchild 5532 data sheet 558
feedback resistor 472
fifteen-way D-type connectors 23
fifth order filters: single stage 260; three stages 225–230, 226, 226–228, 257–258, 259, 259; two stages 228–229, 229
filler-driver crossovers 111–112, 111–113
filter cutoff frequencies 148
filter order in signal path 516–518
filter performance 297–298; see also distortion; noise
filters 145; active (see active filters); 1st order 148, 241, 241–242; 2nd order 149, 198–209, 242–249; 4th order 215–224, 225; adding zeros to more complex 176–181, 178–181; Akerberg-Mossberg highpass 279–280, 280; Akerberg-Mossberg lowpass 276–279, 277–279; allpass (see allpass filters); all-stop 147; amplitude peaking and Q 150–151, 152; bandpass (see bandpass filters); bandwidth definition 237–238, 237–239, 238, 262–264, 262–264; biquad 276; brickwall 147; characteristics 149–162, 150–167; elliptical 179–181, 180–181, 342; Gaussian 184–185, 186–187; Halpern 193; higher order 149, 167–176, 168, 169, 170–171, 172, 173–174, 174–176; highpass (see highpass filters); Laguerre 190; Legendre-Papoulis 187–189, 188–189, 189; lesser-known characteristics of 182, 182–193, 183, 184, 185–189, 189, 191–192; linear-phase 182, 182–183, 183, 184; lowpass (see lowpass filters); multiple-feedback 272–275, 276; notch (see notch filters); order of 147; performance 297–298 (see also distortion; noise); state-variable (see state-variable filters (SVF)); subsonic 263–264, 263–264; synchronous 190–193, 191, 191–192; Tow-Thomas biquad lowpass and bandpass 280–285, 281–283, 284–285; transitional 182; ultraspherical 193; variable-frequency highpass 267–270, 268–269; variable-frequency lowpass 239, 239–240; see also Bessel filters; Butterworth filters; Chebyshev filters; design, filter; highpass filters; Linkwitz-Riley filters; lowpass filters
first order crossovers 63–69, 64–68; Solen split crossovers 69–70, 69–70; subtractive 132–133, 132–133; 3-way 70
first order filters: allpass 356–364, 357–363; distortion and noise in 362, 362–363; highpass 241, 241–242; lowpass 148, 197, 197, 556–557,
fixed frequency and low Q equalisers 398–399, 398–400
fixed-gain amplifiers 514
flatness of summed amplitude/frequency response on-axis 51
fourth order crossovers 92–107, 107–108; Bessel 99, 99; Butterworth 93–95, 94–95, 135, 136–137, 137; Gaussian 103–106, 104–105; Legendre 106–107, 107–108; linear-phase 101–103, 102–103; Linkwitz-Riley 95–97, 96–98; 1.0 dB-Chebyshev 99–101, 100–101; subtractive 135, 136–137, 137
fourth order filters: highpass 251–257, 258, 317–318, 318; lowpass 215–224, 225, 314–317, 315–317; noise in 331; state-variable 293–295, 294–295
frequencies: characteristic 148; filter cutoff 148
frequency offsets, determination of 109–110, 110
frequency response, negligible impairment of 56
frequency scaling, filter 202–204
function of crossovers 1
gain structures 510–513, 511, 626–627
galvanic isolation 562
ganged potentiometers 581
Gauss, Johann Carl Friedrich 185
Gaussian 4th order crossover 103–106, 104–105
Gaussian distribution 431, 431–435, 432, 437, 437
Gaussian filters 184–185, 186–187
Gaussian resistors 433
ground-cancelling outputs 605–606, 606
ground voltages 562
Halpern filter 193
Hardman, Bill 121
Heinzerling, Christhof 132
HF-boost and LF-cut equalisers 393–395, 393–395
HF-cut and LF-boost equalisation 395–398, 396–397
HF signal path 628–632, 629, 630, 632, 633
Hifi News 32
higher order crossovers 108–109
higher order filters 149, 167–168; allpass 373–379, 374–379, 376; Bessel 173–174, 174, 174; Butterworth 168, 168–172, 169, 170–171; Chebyshev 175–176, 175–176; Linkwitz-Riley 172, 172–173, 173
high-impedance balanced inputs 582
high-level inputs, subwoofers 532–533
high-level outputs, subwoofers 533
highpass filters 146–147, 499; 1st order 241, 241–242; 2nd order 242–247; 3rd order 248, 248, 248–249, 312–314, 314; 4th order 251–257, 258; 5th order 257–258, 259, 259; 6th order 260–262; Akerberg-Mossberg 279–280, 280; bandwidth definition 262–267, 262–267; Butterworth single-stage 252–256, 253, 253–255, 256; components 243; defined gains 245, 245–246, 246; distortion in 2nd order 308–310, 309, 323, 323; distortion in 3rd order 312–314, 313–314; equal resistors 244, 244–245; input impedance 262; Linkwitz-Riley single stage 254–256, 255, 256; multiple-feedback 274–275, 274–276; noise in 329–332; non-equal capacitors 247; with other filter characteristics 256, 257, 258; single-stage 249; single-stage 5th order 260; subsonic filters 263–264, 263–264; three stages 260–262, 261, 261; Tow-Thomas biquad 286–288, 287, 326–327, 326–327; two stages 3rd order 248, 248, 248–249; two stages 4th order 251, 252, 252; two stages 5th order 259, 260, 260; unity gain 243–244; variable-frequency 267–270, 268–269
highpass subsonic filter 534
high-Q bandpass filters 334–335, 335
Hill, Alan 32
home entertainment crossovers 535–536; fixed frequency 536; multiple variable 536; variable frequency 536
home entertainment subwoofers 531–532; crossover frequency control (lowpass filter) 534; crossover in/out switch 534; high-level inputs 532–533; high-level outputs 533; highpass subsonic filter 534; level control 533; LFE input 533; low-level inputs (balanced) 532; low-level inputs (unbalanced) 532; mono summing 533; phase switch (normal/inverted) 534; power amplifiers for 536–537; signal activation out of standby 535; variable phase control 535
horn-loaded subwoofers 530
horn loudspeakers 29
impedance-balanced output 603
in-amps 583
IN+ and IN− 559
input amplifier functions 556
input impedance: highpass 262; lowpass 234
input level controls, system design 499
input overvoltage protection 592, 592–593
instrumentation amplifier 583, 583–584; applications 584–585; at unity gain 588–590, 589–590; with 4x gain 585–588, 585–588
integration, subwoofer 537–538
intermodulation distortion 500
internal signal levels 555–556, 556
Inverse Chebyshev filters 177–178, 178–179
inverting ground-canceling output 605–606, 606
Ionophone speakers 32
isobaric subwoofers 529
Laguerre filters 190
lapped screen 561
Legendre crossover 106–107, 107–108
Legendre-Papoulis filters 187–189, 188–189, 189
level control, subwoofers 533
LFE input 533
LF path: 400 Hz Linkwitz-Riley lowpass filter 635; no time-delay compensation 636
linear phase crossovers 56–57; 4th order 101–103, 102–103
linear-phase filters 182, 182–183, 183, 184
line arrays: amplitude tapering 37, 38; CBT (constant beamwidth transducer) 39; frequency tapering 37–39, 38
line inputs and outputs: balanced cables and interference 560–562; balanced connectors 562–563; balanced input stage, variations on 576; balanced interconnections 559, 559, 560; balanced signal levels 563; basic electronic balanced input 565–567, 566, 566; combined unbalanced and balanced inputs 576–577; common-mode rejection ratio (CMRR) 563–565, 564; electronic vs transformer balanced inputs 563; external signal levels 555; high input impedance balanced inputs 582, 582–583; input amplifier functions 556; input overvoltage protection 592, 592–593; instrumentation amplifier 583, 583–584; instrumentation amplifier applications 584–585; instrumentation amplifier at unity gain 588–590, 589, 590; instrumentation amplifier with 4x gain 585–588, 585–588; internal signal levels 555–556, 556; low-noise balanced inputs 593–598, 595, 597; noise and balanced inputs 593; practical balanced input 573–576, 575, 576; self variable-gain balanced input 581, 581–582; Superbal Input 577–578, 578; switched-gain balanced inputs 578, 578–580; transformer balanced inputs 590–592, 591; ultra-low-noise balanced inputs 598–600, 599, 600–601; unbalanced inputs 556–558, 557; variable-gain balanced inputs 580, 580–581
line isolating transformer 607
line or area arrays 539
line outputs: balanced outputs 606, 606–607; ground-cancelling outputs 605–606, 606; output transformer frequency response 608, 608–609; transformer balanced outputs 607, 607–608; transformer distortion 609–610, 610; reducing 611–614; unbalanced outputs 603–604, 604; zero-impedance outputs 604–605, 605
Linkwitz, Siegfried 59
Linkwitz-Riley 4th-order crossover 626, 629
Linkwitz-Riley crossovers: cutoff frequencies 148; 2nd order 78, 78–79; 3rd order 86–87, 87–89; 4th order 95–97, 96–98
Linkwitz-Riley filters 148, 153, 155, 156–157, 513, 516; 4th order highpass 254–256, 255, 256; loading effects 234–235, 235; with other filter characteristics 256, 257, 258; single stage 221, 221–224, 222, 223, 224, 254–256, 255, 256; up to 8th order 172, 172–173, 173
LM4562 opamps 485–486; common-mode distortion 486–489
LME49990 opamps 489–491; common-mode distortion 491–492; in a voltage-follower circuit 493
lobing and beaming 2–3, 3; MTM tweeter-mid configurations for 33–34
Loudspeaker Design Cookbook 68
loudspeakers: air-motion transformers 31; in automotive audio 5; auxiliary bass radiator (ABR) 28; basic arrangements 25, 25; beaming and lobing 2–3, 3; bi-amping and bi-wiring 6–8, 7; cables for 8–9; CBT (constant beamwidth transducer) line arrays 39; design references 659–660; diffraction 39–44, 40–44; disadvantages of active crossovers and 14–15; Doppler distortion 48; drive unit distortion 47–48; electromagnetic planar 30–31; electrostatic 29–30; equalisation of 387–393; horn 29; line array amplitude tapering 37, 38; line array frequency tapering 37–39, 38; matching crossovers and 20–21; modulation distortion 46–47; MTM tweeter-mid configurations 33–34; passive crossovers 4, 4; plasma arc 31–32; reflex (ported) 27–28; ribbon 30; rotary woofer 32–33; sealed-box 26, 26–27; sound absorption in air and 44–46, 45–46; transmission line 28–29; vertical line arrays 34–39, 35–36, 38
loudspeakers design references 457–458, 465–466, 655
low-frequency effects (LFE) channel 535
low-impedance passive output attenuator 519
low-level inputs (balanced) 532
low-level inputs (unbalanced) 532
low-noise balanced inputs 593–598, 595, 597; card 598; in real life 598
low-noise preamplifier 582
lowpass filters 146, 198; 1st order 197; 2nd order 198–209, 305–307, 306–308; 3rd order 209–215, 311–312, 311–312; 4th order 215–224, 225; 5th order 225–232; 6th order 230–234; Akerberg-Mossberg 276–279, 277–279; with attenuation 236, 236–237; bandwidth definition 237–238, 237–239, 238; components 199; component sensitivity 202, 206, 206–207; defined gains 207, 208, 208; distortion in 2nd order 305–307, 306–308, 322, 322–323, 324–326, 325; distortion in 3rd order 311–312, 311–312; equal capacitor 204, 204–206, 205; filter components 199; input impedance 234; loading effects 234–235, 235; multiple-feedback 273, 272, 274–275, 274–276; noise in 329–332; non-equal resistors 207, 209, 214–215, 215, 224; optimisation 209; single stage 210–214, 211, 212–213, 213–214; single stage Butterworth 217–219, 218–220, 221, 232–234, 233, 233–234; single stage Linkwitz-Riley 221, 221–224, 222, 223, 224; single stage 5th order 229, 229, 229–230; single stage 6th order 232–234, 233, 233–234; single stage with non-equal resistors 224, 225; single stage with other filter characteristics 224; three stage 6th order 230–232, 231, 231–232; three stages 5th order 225–228, 226, 226–228; for time delays 382–383, 382–383; Tow-Thomas biquad 280–285, 281–283, 284–285, 324–326, 325; two stage 3rd order 209, 209–210, 210; two stages 5th order 228–229, 229; two stage 4th order 215–217, 216, 216–217; unity gain 199, 199–202, 201; variable-frequency 239, 239–240
magnetic coupling 562
magnetic-planar loudspeakers 30–31
metal electrode face-bonded (MELF) surface-mount resistors 427
metal film resistors 426
Metallica 510
metal oxide resistors 426
metering 501
MID/HF crossover frequency 502
MID/HLF/MID crossover frequency 502
Miller, Ray 155
Mini-DIN connectors 22
minimum phase crossovers 57
mixed capacitors in low-distortion 2nd order filters 310, 310–311
mixed feedback 612
mode switching in electronic crossover 502
Moir, James 59
monopole radiators 528
mono summing 533
motional feedback 13
motional feedback (MFB) loudspeakers 543–544, 544; acceleration 548–551; history 544; position 544–545; velocity 545–548
motional feedback of velocity 546
MTM tweeter-mid configurations 33–34
multi-band distortion 6
multiple-feedback filters (MFB) 272–273; 2nd order highpass 274; 2nd order lowpass 273, 273; 3rd order 274–275, 274–276; bandpass 333–334, 334; distortion in 321, 321–323, 322–323; noise in 331–332
multi-point bipolar peak detector 521
NE5532 opamps 471
Neville Thiele Method™ (NTM) crossovers 125–127, 126–129
New Order, the 210, 227, 248, 342, 343
nickel-chromium (Ni-Cr) film 427
nine-way D-type connectors 22–23
noise: in active filters 327–328; bandwidth and 328–329, 328–329; and distortion in 1st order allpass filters 362, 362–363; and distortion in 2nd order allpass filters 368, 368–369; and distortion in 3rd order allpass filters 370–373, 371–373; headroom, and internal levels 503–504; index 442; in 2nd order filters 329–330, 331–332; opamps 460–461; in 3rd order filters 330–331; in 4th order filters 331; in Tow-Thomas filters 332
noise analysis: HF path 640–641; input circuitry 639–640; LF path 642
noise and balanced inputs 593
noise figure (NF) 593
noise performance 512; input circuitry 643–646; power amplifier noise 646–647
non-all-pole crossovers 61
non-electrolytic capacitor: non-linearity 449–453; tolerance 446
non-equal capacitors 247
non-equal resistors 207, 209, 214–215, 215, 224, 225
non-inverting ground-canceling output 605–606, 606
non-linear junction capacitance 592
non-polarised DC-blocking capacitor 603
non-standard slopes, equalisation with 415–421, 416–421
normal distribution see Gaussian distribution
notch crossovers: elliptical filter 121–125, 122–124; Neville Thiele Method™ (NTM) 125–127, 126–129
notch filters 146–147, 335–336, 336; Bainter 337–342, 340, 342; Boctor 343–344, 344; bridged-differentiator 342, 343; 1-bandpass notch filter 337; other 345; simulating 345; Tow-Thomas biquad 285–286, 286; Twin-T 336–337, 337
Ohm’s acoustic law 58
OP27 496
opamp: common-mode rejection ratio (CMRR) 570; frequency response 569–570, 569, 570; gain 568, 568–569, 569
opamps 459; 5532: common-mode distortion 474–477; output loading in shunt-feedback mode 472–474; output stage biasing 477–482; series feedback 472–474; with shunt feedback 471–572; versions 482; 5534 472, 483–484; AD797 492–494; LM4562 485–486; common-mode distortion 486–489; LME49990 489–491; common-mode distortion 491–492; NE5532 471; OP27 494–497; price per package 465; properties: bias current 463–464; common-mode distortion 467–468; common-mode range 463; cost 464–465; distortion due to loading 466–467; input offset voltage 463; internal distortion 465–466; noise 460–461; slew rate 462; selection 497–498; surveyed 468; test circuits 468; TL072 469, 469–470, 470; types 460
opamp supply rail voltages 615–616, 616
opamp voltage noise 513
order of filters 147
output attenuators 506–507, 636–638
output level controls 518–519; system design 500
output mute switches, system design 500
output phase-reverse switches, system design 500
parametric equalisers 405, 405–406
parasitic tweeters 2
passive components for active crossovers, capacitors: arbitrary capacitance values 446–447; electrolytic capacitor non-linearity 454–457; non-electrolytic capacitor non-linearity 449–453; shortcomings 447–449; values and tolerances 445–446
passive components for active crossovers, resistors 425–428; arbitrary resistance values 438–439; combinations 439–441; Gaussian distribution 431–435; Johnson and excess noise 441–442; non-linearity 443–445; surface-mount resistors 427–428; through-hole resistors 426–427; uniform distribution 437–438; value distributions 435–436; values and tolerances 428–430
passive components for active crossovers component values 425
passive preamplifiers 557
peak-detect indicators 501
peak-to-peak ripple amplitude 617
performance, filter 297–298; see also distortion; noise
phase inversion 566
phase-invert switches 520
phase response 53
phase switch (normal/inverted) 534
phono connectors 562
polyester capacitors 451
polyethylene terephthalate 449
polypropylene capacitors 447, 452
potentiometers 581
power supply design: ±15 V supply designing 616–619, 617, 618; ±17 V supply designing 619, 619–620; for discrete circuitry 624, 624; dual supplies from a single winding 622, 622–623; mutual shutdown circuitry 623, 623–624; opamp supply rail voltages 615–616, 616; ripple performance 621, 621, 621–622; variable-voltage regulators 620, 620–621, 621, 621
power supply rejection ratios (PSRR) 615
practical balanced input 573–576, 575, 576
preamplifier-crossover-power amplifier chain 506, 507
PSRR 615
Q: dip equalisers with high Q 402–404, 402–405; filter amplitude peaking and 150–151, 152; high-Q bandpass filters 334–335, 335; sealed-box loudspeakers 26, 26–27; variable centre frequency and low Q equalisers 400–402, 401
quasi-floating output 607
raised internal levels 504–506
recommended supply voltage 615
reflex (ported) loudspeakers 27–28
reflex (ported) subwoofers 527
relay output muting 501
reliability, negligible impairment of 56
requirements, crossover: acceptable group delay behaviour 53, 53–54; acceptable phase response 53; acceptable polar response 52–53; adequate flatness of summed amplitude/frequency response on-axis 51; general 51–54; negligible extra distortion 55–56; negligible extra noise 54–55; negligible impairment of frequency response 56; negligible impairment of reliability 56; negligible impairment of system headroom 55; sufficiently steep roll-off slopes between the filter outputs 51–52
resistors 425–428, 594; arbitrary resistance values 438–439; chip surface-mount (SM) resistors 427; combinations 439, 439–441; E24 resistor 429, 430; E96 resistor 429; excess noise 441, 442, 442; Gaussian distribution 431–435; Johnson and excess noise 441–442; MELF surface-mount resistors 427; non-linearity 443–445, 444; surface-mount resistors 427–428; thick-film SM resistors 427; thin-film resistors 427; through-hole resistors 426–427; types 426; uniform distribution 437–438; value distributions 435–436; values and tolerances 428–430; voltage coefficients 443
reverse-biased regulators 618
ribbon loudspeakers 30
ripple performance 621, 621, 621–622
room interaction correction 390–393, 392
ruthenium oxide (RuO2) 427
Sallen, R. P. 198
Sallen & Key highpass filters see highpass filters
Sallen & Key lowpass filters see lowpass filters
sealed-box loudspeakers 26, 26–27
sealed-box (infinite baffle) subwoofers 526–527
second order crossovers 70–81, 82–83; 1.0 dB-Chebyshev 80–81, 81–82; Bessel 79–80, 79–80; Butterworth 71–78, 72–77, 149; Linkwitz-Riley 78, 78–79;
second order filters: allpass 364–369, 365–368; distortion in multiple-feedback 321, 321–323, 322–323; distortion in 2nd order 305–310, 306–309; distortion in Tow-Thomas 324–326, 325; highpass 242–247, 274, 308–310, 309; lowpass 149, 198–209, 273, 273; mixed capacitors in low-distortion 310, 310–311; noise in 329–330, 331–332; state-variable 292–293, 293
security cover 501
security screws 501
Self variable-gain balanced input 581, 581–582
series resistance 9
servospeaker method 545
shunt-feedback amplifier 472, 477
shunt-feedback circuit 515; 5532 distortion 473, 474
shunt-feedback mode 493
shunt protection diodes 618
signal activation out of standby 535
signal-present indicators 501
signal summation 352, 352–353, 353
signal-to-noise (S/N) ratio 499, 503, 508, 515, 516
simulations: distortion 318–320, 319; notch filter 345
single-amplifier biquad (SAB) filters 276
single-opamp 5534 460
single stage filters: 4th order 314–318, 315–318; 5th order 229, 229, 229–230, 260; 6th order 232–234, 233, 233–234, 262; Butterworth 217–219, 218–220, 220, 232–234, 233, 233–234, 252–253, 253, 253–254; distortion in (see distortion); Linkwitz-Riley 221, 221–224, 222, 223, 224, 254–256, 255, 256; noise in 330–331; with non-equal resistors 224, 225; with other filter characteristics 224, 256, 257, 258; 3rd order 249, 311–312, 311–312
sixth order filters: single stage 232–234, 233, 233–234, 262; three stages 230–232, 231, 231–232, 260–262, 261, 261
slew rate 462; limiting distortion 466
Small, Dick 131
small-signal audio equipment 425
Solen split crossovers 69–70, 69–70
sound absorption in air 44–46, 45–46
sound pressure level (SPL) 36, 44–46, 45–46; allpass crossovers and 62
sound-reinforcement crossovers 501
sound-reinforcement subwoofers 538–539; cardioid subwoofer arrays 539; line or area arrays 539
Sowter 3292 output transformer 608, 609–610, 610
speaker protection 500
spiral arrays 37
spiral-format film resistors 436
St. Paul’s cathedral 36, 37, 38–39
state-variable filters (SVF) 288–292, 289, 290, 291–292, 502; 2nd order, variable-frequency 292–293, 293; 4th order, variable-frequency 293–295, 294–295; other orders of 295
statistical noise 432
stereo hi-fi balanced interconnections 562
straight-line arrays 34, 35, 37
subjectivism in crossover design 23
subsonic filters 263–264, 263–264, 499–500; combined ultrasonic and 264–267, 265–267
subtractive crossovers 131–132; 1st order 132–133, 132–133; 2nd order Butterworth 133–134, 134–135; 3rd order Butterworth 135, 136; 4th order Butterworth 135, 136–137, 137; delay lines for 379–381, 380–381; performing the subtraction for 141–142, 142–143; with time delays 137–141, 138–141
subwoofer drive units 530
subwoofers: applications 525; automotive audio subwoofers 540–541; aux-fed subwoofers 539–540; auxiliary bass radiator (ABR) subwoofers 527; bandpass subwoofers 528–529; dipole subwoofers 529–530; enclosure 526; hi-fi subwoofers 530–531; horn-loaded subwoofers 530; integration 537–538; isobaric subwoofers 529; reflex (ported) subwoofers 527; sealed-box (infinite baffle) subwoofers 526–527; subwoofer drive units 530; technologies 525–526, 526; transmission line subwoofers 528
subwoofers, home entertainment 531–532; crossover frequency control (lowpass filter) 534; crossover in/out switch 534; high-level inputs 532–533; high-level outputs 533; highpass subsonic filter 534; level control 533; LFE input 533; low-level inputs (balanced) 532; low-level inputs (unbalanced) 532; mono summing 533; phase switch (normal/inverted) 534; power amplifiers for 536–537; signal activation out of standby 535; variable phase control 535
subwoofers, home entertainment crossovers 535–536; fixed frequency 536; multiple variable 536; variable frequency 536
subwoofers, sound-reinforcement 538–539; cardioid subwoofer arrays 539; line or area arrays 539
sufficiently steep roll-off slopes between the filter outputs 51–52
supply filtering 448
surface-mount resistors 427–428, 428
switchable crossover modes 501–502
switched-gain balanced inputs 578, 578–580
Sydney Town Hall, Australia 33
symmetric crossovers 62
synchronous filters 190–193, 191, 191–192
system design, active crossover: active gain controls 514–516; amplitude/frequency distribution 507–510; circuit noise and low-impedance design 504; distributed peak detection 520–522; filter order in signal path 516–518; gain structures 510–513; mute switches 519–520; noise, headroom, and internal levels 503–504; noise gain 513–514; output attenuator 506–507; output level controls 518–519; phase-invert switches 520; power amplifier considerations 522; raised internal levels 504–506; switchable crossover modes 501–502
system design, active crossover, features of 499; control protection 500–501; input level controls 499; output level trims 500; output mute switches 500; output phase-reverse switches 500; subsonic filters 499–500; ultrasonic filters 500; usually absent, metering 501; usually absent, relay output muting 501
system headroom, negligible impairment of 55
Thevenin-Norton transformation 442
thick-film resistors 426
thick-film SM resistors 427
Thiele, Neville 125
Thigpen, Bruce 32
thin-film resistors 427
thin-film surface-mount resistors 445
third-harmonic distortion 450
third order crossovers 83–92, 84–93; 1.0 dB-Chebyshev 89, 91–92, 92, 93; Bessel 89, 90–91; Butterworth 84–86, 84–86, 135, 136; Linkwitz-Riley 86–87, 87–89
third order filters: allpass 369–373, 369–373; distortion in 311–314, 311–314; highpass 248, 248, 248–249, 274–275, 274–276; lowpass 209–215, 274–275, 274–276; multiple-feedback 274–275, 274–276; noise in 330–331
Thomson, W. E. 155
three stages highpass filters: 5th order 257–258, 259, 259; 6th order 260–262, 261, 261
three stages lowpass filters: 5th order 225–228, 226, 226–228; 6th order 230–232, 231, 231–232
through-hole resistors 426–427, 430, 443
time-delay filters 631–632; 1st order allpass filters 356–361, 357–361; 2nd order allpass filters 364–369, 365–368; 3rd order allpass filters 369–373, 369–373; allpass filters in general 355–356, 356; cascaded 1st order allpass filters 363, 363–364; filter technology 355; higher order allpass filters 373–379, 374–379, 376; physical methods of 353–354, 354; requirement for delay compensation and 347–348, 348; sample crossover and delay filter specification 355; signal summation 352, 352–353, 353
time delays: calculating 349–352, 350–351, 351; lowpass filters for 382–383, 382–383; for subtractive crossovers 379–381, 380–381; subtractive crossovers with 137–141, 138–141; variable allpass 381–382
topology, crossover 113–118, 114–118
Tow-Thomas biquad highpass filters 286–288, 287; distortion in 326–327, 326–327; noise in 332
Tow-Thomas biquad lowpass and bandpass filters 280–285, 281–283, 284–285; distortion in 324–326, 325
Tow-Thomas biquad notch and allpass responses 285–286, 286
transfer distortion 465
transformer balanced inputs 590–592, 591
transformer balanced outputs 607, 607–608
transformer coupling 592
transformer distortion 609–610, 610; reducing 611–614
transitional filters 182
transmission line loudspeakers 28–29
transmission line subwoofers 528
Trinity Church, Wall Street, New York 32–33
TRW-17 33
tweeters: 1st order crossovers and 63–64; active crossovers and 10; necessity of crossovers due to small size of 2; parasitic 2; ribbon loudspeakers and 30
Twin-T notch filter 336–337, 337
two stage filters: 3rd order 209, 209–210, 210, 248, 248, 248–249; 4th order 215–217, 216, 216–217, 251, 252, 252; 5th order 228–229, 229, 259, 260, 260
types, crossover: 1.0 dB-Chebyshev 80–81, 81–82, 89, 91–92, 92, 93, 99–101, 100–101; 1st order 63–70, 64–70; 2nd order 70–81, 82–83; 3rd order 83–92, 84–93; 3 way 70; 4th order 92–107, 107–108; allpass and constant-power 62–63; all-pole and non-all-pole 61; Bessel 79–80, 79–80, 89, 90–91, 99, 99; Butterworth 71–78, 72–77, 84–86, 84–86, 93–95, 94–95; constant-voltage 63; crossover topology and 113–118, 114–118; determining frequency offsets for 109–110, 110; Duelund 113; filler-driver 111–112, 111–113; Gaussian 103–106, 104–105; higher order 108–109; Legendre 106–107, 107–108; linear-phase 56–57, 101–103, 102–103; Linkwitz-Riley 78, 78–79, 86–87, 87–89, 95–97, 96–98; Solen split 69–70, 69–70; symmetric and asymmetric 62;
ultra-low-noise balanced inputs 598–600, 599, 600–601
ultrasonic and subsonic combined filters 264–267, 265–267, 628
ultrasonic filters 500
ultraspherical filters 193
unbalanced inputs 556–558, 557, 566; circuit resistances 574
unbalanced outputs 603–604, 604
unity gain: 2nd order highpass 243–244; 2nd order lowpass 199, 199–202, 201
US Crossover Patents 653
variable allpass time delays 381–382
variable centre frequency and low Q 400–402, 401
variable-frequency filters: highpass 267–270, 268–269; lowpass 239, 239–240; other orders of state-variable 295; state-variable 2nd order 292–293, 293; state-variable 4th order 293–295, 294–295
variable-gain balanced inputs 580, 580–581
variable output voltage IC regulators 620, 620
variable phase control 535
variable-voltage regulators 620, 620–621, 621, 621
vertical line arrays 34–39, 35–36, 38
voice coil heating 11
voltage-doublers 622
voltage-follower configuration 491
voltage noise density 600
von Helmholtz, Hermann 58