Harald Bode - History of Electronic Sound Modification

7/28/2019 Harald Bode - History of Electronic Sound Modification

http://slidepdf.com/reader/full/harald-bode-history-of-electronic-sound-modification 1/28

0 I NTRODUCTI ON

730

1- 0

H story of El ect roni c Sound Mod f i cat i on'

` ) 6 . ) - t. cor msV

The hi story of el ect roni c sound modi f i cat i on i s asol d as t he hi story of el ect roni c musi cal i nst ruments andel ect roni c sound t ransmssi on, recordi ng, and repro-ducti on .

Means f or modi f yi ng el ect r i cal l y generat ed soundhave been known si nce t he l at e 19t h cent ury, whenThaddeus Cahi l l created hi s Tel harmoni um

Wth t he advent of t he el ect roni c age, spurr ed f i r s tby t he i nvent i on of t he el ect ron t ube, and t he mor erecent devel opment of sol i d- state devi ces, an ast oundi ngvari ety of sound modi f i ers have been creat ed f or f i l -t e r i n g ,di stort i ng, equal i zi ng, ampl i t ude and f r equencymodul at i ng, Doppl er effect and r i ng modul at i ng, compressi ng, reverberat i ng, repeati ng, f l angi ng, phasi ng,pi tch changi ng, chor usi ng, f requency shi ft i ng, ana-l yzi ng, and resynt hesi zi ng nat ural and a r t i f i c i a lsound

I n t hi s paper some hi ghl i ghts of hi stori cal devel -opment are revi ewed, coveri ng t he t i me f rom 1896 t ot he present .

1 THE ELECTROMECHAN CAL ERA

To gi ve a more compl et e account on t h i shi story, i ti s i mpor t ant t o i ncl ude t he t i me span that preceded t hepurel y el ect roni c era, and al so t o i ncl ude some hi storyof el ect roni c (and el ectri cal ) i nst r uments whose soundmodi f i cat i on devi ces f ormed an i nt egral par t of t heenti re system

A cl assi c case i s t he Tel harmoni um by ThaddeusCahi l l ( F i g. 1) , whi ch was bui l t around 1896 [1]-[10] .Thi s i nst r ument used t he pr i nci pl e of addi t i ve t onesynthesi s f or sound mani pul ati on and modi f i cat i on . Thei ndi vi dual t one col ors were b u i l tup from f undament al sand over t ones, generat ed by huge dynamos . For t hepurpose of generati ng pure sine waves f or t he synt hesi s,t he i ndi vi dual generat or coi l s were t uned w t h capac-i t o r s ,anot her means of sound modi f i cat i on .

* Based on papers presented at t he M dwest Acoust i csConfer ence, Chi cago. 1981 Apri l 25 and at t he 70th Con-vent i on of the Audi oEngi neeri ng So c i e t y,New York, 1981Oct . 30-Nov . 2) . Manuscr i pt recei ved 1984 J une 18.

HARALD BODE

Bode Sound Co . , North Tonawanda, NY 14120, USA

2 THE ELECTRON C ERA

PAPERS

After t he Tel harmoni um and especi al l y af t er t hei nvent i on of t he vacuum ube, scores of el ect roni c (andel ect roni c mechani cal ) musi cal i nst rument s wer e i n-vent ed w t h sound modi f i cat i on features . The Hammondorgan i sof speci al i n t e r e s t ,si nce i tevol ved from Cahi l l ' swor k . Many not abl e i nvent i ons i n el ect roni c soundmodi f i cat i on are associ ated w t h t h i si nst rument , whi chw l l be di scussed l ater .

Ot her i nst r ument s of t he earl y 1930s i ncl uded t heTrautoni umby t he German F Traut wei n, whi ch wasb u i l ti n several versi ons . The Trautoni um used reso-nance f i l t e r st o emphasi ze sel ect i ve overt one regi ons,cal l ed f ormant s [ I 1] - [ 14] . I n contr ast, t he German J orgMager b u i l tan organl i ke i nst r ument f or whi ch he usedl oudspeakers w t h al l types of dri ver syst ems and shapest o obt ai n di f ferent sounds .

I n 1937 t he aut hor creat ed t he War bo For mant organ,whi ch had ci rcui try f or envel ope shapi ng as wel l asmor e compl ex f i l t e r st han t hose used before . I t had twos e t s of f i l t e r sand a f our- voi ce assi gnment keyboard[ 15] t hrough whi ch, f or i nst ance, voi ces 1 and 3 coul dbe assi gned t o t he f i r s t f i l t erand voi ces 2 and 4 t o t hesecond f i l t e r( F i g. 2) . By maki ng t he pass regi ons oft he f i l t e r smut ual l y excl usi ve, compl ementary t onecol ors coul d be produced, whi ch sounded very pl easi ngt o t he ear [ 16] , [ 17] .

I n t he l a t e 1930s t he Hammond Novachord was cre-ated, whi ch al so had f or mant f i l t e r sf or over t one mod-i f i c a t i o nand envel ope shapi ng t o produce t ones l i k e

those of wnd and str i ng i nst r uments [18], [ 19] .

An i nt eresti ng means of sound modi f i cat i on i sf oundi n t he El ectr ochord by Oscar Vi er l i ng [ 16] and i n t heM essner pi ano [20]-[23] . I t was f ound t h a t t onal qual -i t i e scoul d be dramat i cal l y modi f i ed by changi ng t hel ocat i on of pi ckups ( i n t h i scase capaci t i ve) al ong t hestri ngs . For i nst ance, when pi cki ng up the osci l l at i onsat t he mdpoi nt, al l even harmoni cs wou d di sappear ,l eavi ng onl y t he odd har moni cs, t hus produci ng a hol -l ow cl ar i net l i ke sound Pl aci ng t he pi ckup at one t hi rdof t he st r i ng' s l engt h, t he t h i r d , si xth, and so f or t hhar moni cs wou d be cancel ed, and pi ckup poi nts at

J . Aud o Eng Soc . . Vol . 32, No 10 1984 October



PAPERS

other l ocati ons of t he s t r ing l ength woul d pr oduce yetdi f f erent harmoni c structures .

The El ectr ochord as wel l as t he M essner pi ano wereb u i l t wi t hout soundi ng boar ds, t hus el i mnat i ng thei rdampi ng ef f ect and pr oduci ng t ones wi th l onger decayt i mes . The same was t r ue f or t he Les Paul gui t ar, andi t mght be i nteresti ng t o l earn that Paul i nvent ed t hesol i d- body gui t ar as f ar back as 1927 [24] . I n hi s ear l yexper i ment s Paul used t he magnets of t he ol d-st yleheadphones, whi ch were equi pped wi t hs t e e ldi aphr agmsas membr anes . The G bson gui t ar evol ved i n 1941, andi t has s i nce been associ ated wi t h an i ncredi bl e numberand vari ety of sound modi f i cati on devi ces and met hods,some of whi ch w l l be di scussed i n mor e detai l .

From t he begi nni ng one i mpor t ant means of soundmodi f i cati on has been t he t r emol o and t he vi brato, thet r emol o bei ng an ampl i t ude modul at i on [25] and t hevi brato a f r equency modul at i on . I t i si nteresti ng t o not ethat post- sour ce f r equency modul at i on i n i t i a l l yposeda probl em For t h i s reason t he f i r s t Hammond organswere equi pped wi t h means f or ampl i t ude modul at i onor t r emol o .

I n t he md-1940s a del ay l i n e wi t h vari abl e i nduct orswas i nvent ed by Hanert , and af t er t hi sa di f f erent t ypeof vari abl e del ay l i n e wi th a number of del ay t aps anda capaci t i ve scanner was i ncorporated i n t he Hammondorgan (F i gs. 3 and 4) [ 26] , [ 27] . By combi ni ng di rect

TI RE r FYDOARD OF THE I NSTRUMENT FOR PRODUC NG MUSI C BY ELECTR C TY

and t he f r equencymodul at ed si gnal s, a t ype of chor alef f ect was produced [ 28] . Thi s l a i dt he f oundat i on f ort oday' s phasers . I n t he md 1950s W C Wayne, J r. ,proposed and bui l t a pur el y el ect roni c choral tonemodul ator f or t he Bal dw n organ [29] . A di f f erent ap-pr oach f or choral tone modul at i on was t aken by D LBonham i n t he ear l y 1960s [30], af ter he had createdsuccessf ul l y a pur el y el ec t roni c vi brato modul at or i n1958 [ 31] .

A uni que cont ri but i on i n sound modi f i cat i on devi ceswas made by Homer Dudl ey t hrough hi s creati on oft he voder and t he vocoder i n t he l a t e 1930s .

The voder [ 32] was a keyboar d- oper at ed i nst r umentcont r ol l i ng a number of bandpass channel s f or si mu-l at i ng t he resonances of t he human voi ce. Wth t headdi t i on of a tone source cal l ed t he buzz source and anoi se source cal l ed t he hi ss source, vowel s and con-sonants of a speaker were i m t a t ed .

The system became even mor e exci ti ng when t hevoder , bei ng an encoder, was combi ned wi t h a decoder .

Thi s combi nat i on was cal l ed t he vocoder , whi chcompri sed an anal yzer f or anal yzi ng t he speech and a syn-

t hesi zerf or remaki ng t he same speech [33], [ 34] .

For accompl i shi ng t h i s , t he audi o range was s l i cedup i nt o a number of bandpass channel s i n t he anal yzer ,whi ch correspond t o an equal number of bandpasschannel s i n t he synt hesi zer . I n each anal yzer channel

: .Y- v " " : n - mnes ". ! u r" n~ . t of a rmoratm or a pa r t i cul a r i n t r n ai t y. The vihrat i oni make t on" i ns t el ephone rm ~ t . t he other e i i d of a ui tt connect i ng

of the htl erent Ronerat om produce the di f f e r enc es i n t he t ones . - The musi c may he h=d w th equa l vol ume i n the room. , . . . r . . . , . .. . : : t . . . . ,. Lonc - eney m l e s away . .

. Fi g. 1 . Pl ayi ngconsol e of C a h i l lTel har moni um(courtesy Tom Rhea) .

J . Audi o Eng Soc . , Vol . 32, No . 10, 1984 Oct ober

HSTORY OF ELECTRON C SOUND MODIFI CATI ON

731



BODE

a control vol t age i s gener at ed w t h what we now c a l lan envel ope f ol l ower . Thi s control vol t age was t henf ed t o t he contr ol vol t age i nput of a vol t age- cont rol l edampl i f i er i n t he cor r espondi ng synt hesi zer channel .

By l i s teni ng t o t he recordi ngs of t he Dudl ey vocoderone noti ces tha t not onl y t he speech ar t i cul at i on i s bei ngremade but al so t he speech i nfl ecti on, whi ch clear l yi ndi cates t he presence of a pi t ch ext ractor- thatwor ks- as wel l as a pi t ch- t o-vol t age conver t er and avol t age- cont r ol l ed osci l l ator . I n t he cl osi ng secti on oft hi s ar t i c l ea f ewmore aspect s, modi f i cati ons, and ap-pl i cati ons of t he vocoder w l l be di scussed .

Thus f ar i t has been obser ved that one i mpor t antel ement i n sound modi f i cati on devi ces i s r epr esent edby a var i et y of f i l t e r s ,such as t he f or mant f i l t e r sof t heTrautoni umand t he Hammond Novachord, t he compl ement ar y tone f i l t e r sof t he War bo Formant or gan,and t he bandpass f i l t e r sof t he vocoder . Another i n-st r ument w t h st r o ng f or mant f i l t e r swas t he Bode Mel -ochor d ( F i g. 5) ( pr eceded by t he Mel odi um [ 3 5 ] , whi chwas bui l t f or several maj or broadcast stati ons i n WestGer many by t he l a t e 1940s and t he ear l y 1950s . The

Mel ochord was al so equi pped w t h c i r cu i t ry f or t hecontrol of attack and decay envel opes, vi br ato, and t hecapabi l i ty t o pl ay tr avel i ng f ormants, t he f r equency ofwhi ch was keyboard cont rol l ed. I n t he Mel ochord f ort he St ockhausen St udi o i n Col ogne t he modul ar conceptwas adopt ed, by whi ch external r i ng modul at or s, echochamber s, and t he l i k e coul d be i ncl uded i n t he system

Fi g.

2 Compl ement ar y f i l t e rr esponses of War bo For mantorgan .

732

J ~9

6

R43

Ifli 111111 ~~

soon I MMNUM

111

! 02346 8 ? 234

XI681' 23V68 2

[.l 04

V

-~ ~equenz~Hz)V

Fi g .3

. Del ay l i n ef or Hammond organ vi brato u ni t.

[36]-[38] .

A uni que i nst r ument combi ni ng many of t he meansof tone genera t i on and sound modi f i cati on known att hat t i me was t he RCA synt hesi zer ( F i g. 6) , whi ch wascreated under Har r y F O son .

I t made i t s debut i n 1955[ 39] - [ 41] . The RCA synthesi zer i s cont rol l ed by pr e-pr ogrammed punched t ape .

I t has such features as di g-i t a l l y cont rol l ed f i l t e r s , control of attack and decayenvel opes, di gi t al l y cont rol l ed pi tch and waveshapes,random noi se gener at i on, and f r equency and ampl i t udemodul at i on.

Around t he same t i me Les Paul became f amous w t hhi s mul t i t rack gui t ar r ecordi ngs, usi ng t ape speedt ransposi t i on and t he repeti ti on e f f e c t. The wel l - knownpi ece "Whi speri ng" was done i n t he ear l y 1950s . Be-si des bei ng an out st andi ng perf ormer, Paul i s an out -st andi ng i nnovat or . He i ntr oduced t he mul t i t rack r e-cor der [ ei ght t r acks on 1- i nch ( 25- mm t ape] i n coop-erati on w t h Ampex . He al so created Sel Sync . H srepeti t i on effect was done w t h a f i ve- head r ecorder .

H s t ape speeds were i n i t i a l l y60 and 30 i n / s ( 1 . 52 and0 . 76 m s) and l ater r educed t o 30 and 15 i n / s( 0. 76 and

0. 38 m s) . I t was Paul who i nt r oduced t he R AA curve.

AMPLIFI ER

Fi g. 4 . Basi c di agr amof Hammond vi b r at o uni t.

PAPERS

Fi g . 5 . The author t uni ng hi s f i r s tMel ochor d( 1947) .

J . Audi o Eng Soc . , Vo l. 32 , No 10 , 1984 Oct ober



PAPERS

Pri or t o t he tape era, Paul created t he r epet i t i one f f e c ton 16- i n (406-mm di sks w t h f i v epl ayback pi ckupsi n t he same groove w t h t he cut t i ng head Thi s was i n1941 .

Les Paul , of course, st i mul ated many i nnovators ,and due t o hi s success encouraged them o work i n t hef i e l dof new sound effects . Hi s i nf l uence i n many areasi s f e l t t o t h i s day . The aut hor was so i mpr ess ed by hi swork tha t he l at e rdevel oped a sound modi f i cat i onsys-t em consi s t i ng of a number of el ec t roni c modul es , as -

si gned t o two separ at e out put s t hrough a mul t i pl e- headt ape l oopdevi ce [ 42] ( F i g. 7) . These modul es , whi chwi l l be deal t w t h i n more d e t a i l , al so i ncl uded a r i ngmodul at or .

The r ing modul at or was at t he t i me a r el at i vel y l i t t l e -known sound modi f i cat i ondevi ce, mai nl y used i n s i n -gl e- si deband communi cat i on sys t ems . The mai n reasonwas t hat up t o t he m d- or l a t e 1950s i t was known asa s w t c hi ng c i r c u i t , whi ch woul d have sounded t ooharsh t o be usabl e f or sound modi f i cat i on.

I t was onlyaf t er r i ng modul at or s were bui l t w t h di odes, whi choperat e i n t h e square l aw r egi onof thei r t r ansfer f uncti on

( as was t he case w t h cer t ai n german um di odes) , t h a t

J . Audi o Eng Soc , V 0 . 32, No 10, 1984 October

Fi g. 6 RCA synthesi zer (courtesy Tom Rhea) .

H STORY OF ELECTRON C SOUND MOD FICATI ON

they s tar ted t o perf orm as f our - quadr ant mul ti pl i ersand became musi cal l y i nt e r es t i ng ( F i g. 8) [43], [ 44] .

The aut hor ' s modul ar sound modi f i cat i onsyst em wasbui l t i n l at e 1959 t hrough 1960 . I n i t t he mul ti pl i er-t ype r i ng modul at or and other sound modi f yi ngdevi ceswere used, such as an envel ope f ol l ower, a tone-burst-r esponsi ve envel ope generat or, a vol t age-contr ol l edampl i f i er, f or mant and other f i l t e r s , mxers , a pi t c hextractor, a compar at or and f r equency di vi der f or t heextracted pi t ch, and a t ape l oop repeater w t h dualchanne l process i ng[ 45] , [ 46] .

The modul ar concept proved at t ract i ve due t o i t s

versati l i ty, and i t was adopt ed by Rober t Moog whenhe created hi s modul ar synthesi zer i n 1964 Thi s syn-t hes i zer i ncl uded a vari ety of sound modi f i cat i on devi cesand system modul es , such as vol t age-control l edf i l t e r s[47], envel ope genera tor s , vol t age -cont r ol l edampl i -f i e r s , and sampl e/ hol d ci r cui t s . At a l at er dat e Boder i n g modul at or s and Bode f r equency shi f t ers ( whi chw l l be descri bed i n more d e t a i l )were al so added t ot he Moog l i n e .

By t he l a t e 1960s sound effect devi ces such as t he

wahwah appear ed i n t hepopul ar

enter t ai nment f i e l d.

733



The f i r s tsuccessf ul wahwah was reported t o have beent he "Cry Baby, " whi ch ori gi nat ed i n Engl and ar ound1965 .

I t worked w t h germani um tr ansi stors .A qui te

ef f ecti ve wahwah was, of course, t he Moog vol t age-contr ol l ed l ow- pass f i l t e rcapabl e of very pronouncedr esonances, whi ch coul d be act uat ed by a vol t age controlpedal .

I t i s under st ood t hat t he Mutron, an envel ope-act i vat ed vol t age-cont rol l ed f i l t e r , was w del y us eddur i ng t he 70s . [48] .

Anot her popul ar sound effect devi ce, whi ch startedi n t he md 1960s, i s i n t he cat egory of t he so-cal l edfuzz boxes . The story goes t hat t he fuzz started w t hJ e f fBeck maki ng a gui t ar recor di ng by overdri vi ng adef i ci ent pr eampl i f i er of hi s t ape recorder .

The f i r s tsuccessf ul fuzz boxes i ncl ude t he VOX di s-tort i on boost er, whi ch pl ugs i nt o a gui t ar and whi chori gi nat ed i n Engl and i n 1964 At around t he samet i me t he Ar bi t er f uz z f ace appear ed on t he scene [ 49] .

The use of t he fuzz effect i s qui te popul ar w t h gui tars,and i t can be enhanced by ext endi ng t he sustai n t i mew t h compressi on ci rcui t s [ 50] .

Ther e a r e , of course, qui te a number of ot her wahwahs

and fuzz boxes on t he mar ket , al l of whi ch cannot bement i oned w t hi n t he scope of t h i s publ i cati on .

Further el ectr oni c sound modi f i cat i on devi ces t hathave been successf ul t o t h i sdat e are f l angers and phas-e r s , and i t i s of i nt er est t o t r ace t he hi s t or y of thei rdi scovery and desi gn [ 51] , [ 52] .

The f l angi ng effect can be commonl y obser ved out-doors, when a j et f l i e soverhead, and t he di rect soundi s summed i n the ear of t he obser ver w t h t he soundr e f l e c t e dfrom t he gr ound, resul ti ng i n t he cancel l ati onof cert ai n f r equenci es and produci ng t he comb f i l t e re f f e c t ,commonl y referred t o as " j et sound . "

I n t he hi s tory of recor di ng t he story goes t hat w t h

t he i n t e n tt o achi eve doubl e tr acki ng w t h two recorders

Fi g . 7 . Modul ar sound modi f i er by t he author ( 1960) .

Phot o repri nted f rom l e c t r o n i c s ,1961, Dec . 1 . Copyr i ght ® 961,MGrawH l l I nc . A l r i ght s reserved .

734

w t h s l i ght l y di f f erent speeds on t he pi ece "The Bi gHur t , " t he f l angi ng effect was obt ai ned by acci dent .

Paul created t he f l angi ng e f f e c ti n "Mame' s Boogi e"w t h two di sk recorders, one of whi ch had vari abl espeed control ( 1945) . At a l a t e r t i me, w t h the avai l -abi l i t y of tape recorders, f l angi ng was done w t h twot ape recorders, oneof whi ch had var i abl e speed control( F i g. 9) .

A atuous recordi ng made t h i sway was "I tchy-coo Park" by Smal l Faces i n t he l ate 1960s [ 24] . ,

Af t er t he theory of f l angi ng had been est abl i shed f orsome t i me and t he i ndustr y was wai t i ng f or usabl e i n-tegrated c i r c u i t st o make del ay l i n e sof s u f f i c i e n tqual i tyand del ay t i me [53], Ri chard Fact or of Eventi de demonstrated el ectr oni c f l angi ng w t h a practi cal l y "con-t i nuousl y" vari abl e di gi tal del ay l i n e at t he Spr i ngConventi onof t he Audi o Engi neeri ng Soci ety i n 1973[ 54] . Pri or t o t h a t , Eventi de had been exper i ment i ngw t h bucket bri gade devi ces f or several year s [ 55] -[ 57] .

The Eventi de i nstant f l anger was i nt r oduced i n t hespri ng of 1975 .

I t was l a t e rf ol l owedby the pi tch changemodul e f or t he 1745M di gi t a ldel ay l i n e and t hen by

t he model H910 harmoni zer , whi ch was t he f i r s tusabl et r ansposi ng devi ce .

I n contrast t o t he wor k of Factor of Event i de, St evenSt . Croi x of Marshal l El ectroni c concentrated on t hef l e x i b i l i t i e sof a modul at ed del ay l i n e ,whi ch he cal l edt he t i me modul ator and f or whi ch new anal og del ayi nt egrated ci rcui t s were devel oped . Wth t h i s t i memodul ator a l arge vari ety of effects were i ntr oduced,such as aut omat i c doubl e t r acki ng, aut omati c t r i p l et r acki ng, negat i ve f l ange, posi ti ve f l ange, r esonantf l ange, " negat i ve k i l l e rf l ange," posi t i ve k i l l e rf l ange,"vi br at o, ar peggi o, pi tch quanti zi i ng, two-drum sl aps,reverb w t h detune, and others . The Marshal l t i me

modul ator was i nt r oduced t o t he t r ade i n 1976 .

General l y speaki ng, i n f l angers a comb f i l t e reffect

rr

t1

r

Fi g. 8 . Sw tchi ng and mul t i pl i e r - t yper i n gmodul ator s andout putwave shapes . ( a) W t h chopper- t ype o pe r a t i o n( s i l i c o ndi odes) . ( b) W t h mul t i pl i e r - t ypeoperati on ( germani umdi odes) .

J . Audi o Eng . Soc , Vol . 32, No 10, 1984 Oct ober



PAPERS

i s produced where t he spaci ng of t he peaks and not chesequal s t he r eci procal of t he del ay t i me . I n contrast, i nphasers, dependi ng upon t he desi gn paramet er s usedf or t he phase f i l t e r ,t he spaci ng of t he peaks and not chescan be made t o cover equal musi cal i nt erval s [58] . A l l -pass phase f i l t e r shave been known f or anal og comput ersr oughl y si nce t he 1940s . So bas ical l y the t echnol ogywoul d have been avai l abl e t o bui l d phasers at that t i me .

Accor di ng t o one repor t the f i r s tuser of phasers wasDodi e Fi el ds i n t he md 1950s . The Countryman phases h i f t e rbecame known i n t he ear l y 1970s . One of t hesuccessf ul phasers of t he earl y t i mes was t he Maest r ophaser, desi gned by Tom Oberhei m

On t he Moog 12- st age phaser t he number of phasi ngst ages as wel l as t he number of st ages i ncl uded i n t hef eedback l oop coul d be sel ect ed . The Bode Barber pol ephaser ( i ntr oduced i n 1981) i s capabl e of uni di rect i onal( i n f i n i t e )movement of t he comb f i l t e rpeaks and not ches .

A very i mport ant i ngredi ent i n sound modi f i cat i oni s the addi t i on of reverberat i on t o program materi al .

I n t he ol d days, that i s , i n t he 1930s, one used echochambers f or t h i spur pose, and w t h very good resul t s .

But t hey wre expensi ve and space consumng Then i n1941 came t he i nvent i on of t he Hammond spri ng r e -verberat i on devi ce, whi ch was i ncorporat ed i n hi s organt one cabi net [ 59] .

I t al so worked wel l i n st udi os, andi t s of f spri ng are s t i l lpopul ar .

A di f f erent appr oach f orpr oduci ng reverberat i on ef f ects was t aken by D W

Mart i n of t he Bal dw n Pi ano Company, who used coi lspri ngs, whi ch were mechani cal l y coupl ed w t h t hel oudspeaker cone [ 60] .

Anot her way t o produce r everberat i on effects suc-cessful l y i s , of course, w t h t ape repeaters . Af t er t headvent of usef ul del ay l i n e sa r t i f i c i a lreverberat i on be-came f easi bl e w t h t apped del ay l i nes . Schr oeder ofBel l Laborat ori es proposed a system f or nat ural rever-berati on, i ncorporat i ng a number of del ay l i nes andf eedback confi gurat i ons ( F i g . 10) [61] ; {62] . One oft he most successf ul reverberat i on devi ces s t i l l i n uset oday i s t he EMT pl at e r everberat i on devi ce .

As was menti oned bef ore, post - source f r equencymodul at i on i s very i mport ant t o enhance cert ai n programmater i al . The most f amous devi ce t o produce Doppl eref f ect vi brato by rot at i ng l oudspeakers was and i s t heLesl i e t one cabi net . A purel y el ectr oni c syst em f orsi mul at i ng movi ng sound sources was descri bed by J .

M Chowni ng i n 1971 [63], who proposed t he use ofal l of t he requi r ed par amet ers, . i ncl udi ng ampl i t udemodul at i on, f r equency modul ati 4, and reverberati on

Fi g. 9 . Fl angi ng setup w t h t wo t a p e recorders .

J . Audi o Eng Soc . , Vol . 32 . No 10, 1984 Oct ober

H STORY OF ELECTRON C SOUND MOD FICATI ON

i n f our i ndependent channel s t o achi eve t h i s and othermovi ng sound ef f ects . Pri or t o t h i sa system f or "mon-aural - bi naural t r ansmssi on of sound f or pr oduci ng aHaas effect" had been proposed by D W Mart i n i n1959 [ 64] .

Di f f erent and s t i l l rel at i vel y l i t t l e- known soundmodi f i cat i on devi ces are f r equency s h i f t e r s ,whi ch arecapabl e of pr oduci ng qui t e s t a r t l i n geffects . The f i r s tf r equency s h i f t e r swere i ntr oduced i n the 1950s by Heckand Buerck i n West Ger many [65] . They operat ed ont hepri nci pl e of het erodyni ng t he program materi al , f ori nst ance t hrough a 20-kHz carri er i nto a hi gher f r equencyrange passi ng one of t he si debands produced t hrougha si ngl e- si deband f i l t e r(f or i nstance, passi ng 20 kHzt o 30 kHz) and r ehet er odyni ng t hese f requenci es backi nto t he audi o range w t h a carr i er t hat devi at ed f romt he f i r s t ( 20- kHz) carr i er by t he amount of f r equencys h i f t ul t i mat el y desi r ed [66] .

A di ff erent var i ety of f r equency s h i f t e r snow suc-cessful l y i n use operat es on t he phase s h i f t e rand mul -t i p l i e rpri nci pl e [67] , [68] .

A dual phase s h i f t e rmodi f i est he program si gnal t o produce out put si gnal s, whi ch

are i n 90- degree phase rel at i onshi p rel ati ve t o eachother over a range f rom 20 Hz t o 20 kHz . These f eedi nt o t he f i r s t i nput s of two mul t i pl i ers .

A quadr at ur eosci l l ator produces si ne/ cosi ne- rel at ed s h i f tf r equenci es,whi ch are f ed t o t he second i nput s of t he t wo mul t i pl i ers .

The mul t i pl i er output si gnal s are typi cal l y t hose ofr i ng modul at ors . Due t o t h e i rphase rel at i onshi ps oneof t he si debands i s suppress ed when t hey are summedi n t he out put c i r c u i t ,and t he other i s doubl ed i n ampl i tude, thus produci ng a f requency- shi f t ed si gnal .

Frequency shi f ters can be used f or a vari et y of i n-t erest i ng e f f e c t s ,i ncl udi ng t he spi ral i ng echo e f f e c t ,whi ch i s obt ai ned by pl aci ng t h i s sound modi f i er i n t h e

f eedback l oop of a del ay ci r cui t ( or t ape del ay) . I ncooperat i on w t h Robert Moog a speci al model wascreat ed i n 1973 [ 69] - [ 70] , whi ch has an exponenti alcontr ol vol t age t o amount - of - shi f t i nt erf ace, so i t hasa keyboard t racki ng capabi l i t y . Thi s means t h a t unusualt i mbr es set up w t h t he f r equency s h i f t e rcan be mai n-t ai ned over t he ent i re keyboard range .

I n t he 1973 model a beat f r equency quadr at ur e os-c i l l a t o rwas used, whi ch was l a t e rr epl aced by a w de-

Fi g . 10 . Syst em f or n a t u r a lsoundi ng reverberati on ( a f t e rSchoeder [ 6 1 ) ).

735



r ange quadr at ur e osci l l ator ( 0. 02 Hz t o 5000 Hz) t oi mprove t he f r equency s t a b i l i t y( F i g. 11) [ 71] .

A di f f erent category of sound modi f i er s i s t h a t ofdetuni ng devi ces . The har moni zer by Eventi de al r eadyhas been menti oned Ot her products of t h i s ki nd aremanuf act ur ed by Lexi con and MXR o name j us t a f ewThe basi c pri nci pl e of these transposers was f i r s tdemonstrated i n t he l a t e 1940s on t he Spr i nger apparatus,a machi ne w t h mul t i pl e rotati ng t ape heads, whi ch i s

attached t oa

standard t ape recorder.

Another sound modi f i er of t he el ect r omechani calcategory i s t he Phonogen, whi ch has a ci rcul ar ar -rangement of 12 c aps t ans t o change t he t ape speedw t h i n t he 12 steps of t he tempered scal e .

The pi tch- tr ansposi ng i dea f i r s texecut ed by Spr i ngerhas stayed t he same i n t oday' s t ransposi ng devi ces,and t he basi c concept i s t h a t of s l i c i ngup t he programmater i al i n t o a s er i es of spl i ces of suff i c i ent l y shortdurati on and t o compress or expand these s l i c e sbeforer ecombi ni ng them Fi g. 12) .

I n contrast t o usi ng t he s l i c i ng met hod f or pi tcht ransposi ti on, where smoth t ransi t i on i s a mai n ob-

j ecti ve, i t can al so be appl i ed f or t he opposi t e purpose,namel y, t o change t he sound w t h each new s l i c e. Forachi evi ng t h i se f f e c t ,t he sampl e/ hol d met hod i s appl i edby assi gni ng di f f erent sound paramet er s ( for i nst ance,di ff erent f i l t e rf requenci es) t o each segment .

As ment i oned bef ore, f i l t e r i n grepresents a very basi cmet hod of sound modi f i cat i on. A uni que ki nd of f i l t e r

wor t h ment i oni ng i s t he s t r i ng f i l t e rby Moog, compri si ng f our groups of ni ne very sel ecti ve f i l t e r swhi chcan be act i vat ed i n di f f erent conf i gurati ons f or str ongl yaccertuated tone col ori ngs, i nc l udi ng those of str i ngs .

When al l f i l t e r sare act i vated, a t o t a l of 36 resonatorscover t he perf ormance r ange .

Fi nal l y, i n cl osi ng, a f ew mre det ai l s r el at i ng t ovocoders w l l be di scussed .

Long before Dudl ey' s vocoder became known, therewas an el ect romechani cal dri ver u n i t , known as Sono-vox, whi ch i mpar t ed vi brati ons i n t he r ange of voi cef r equenci es t o t he vocal cavi ty system when hel d agai nstthe area of t he l ar ynx, thus subst i tuti ng f or t he vocalcords and maki ng "sems ynt hesi zed" speech possi bl e .

Thi s i n a sense was t he f orerunner of t he a r t i f i c i a ll arynxs t i l l i n use today . Another i nterest i ng devi ce, whi chprec eded t oday' s vocoders, was cal l ed "t hebag, " w t ht he name of Bob Hei l associ at ed w t h i t [ 72] .

I t coul d

be n cknamed "the poor man' s vocoder . "I t

consi st edof a l oudspeaker dri ver system w thv vi nyl t ube fromt h i s dri ver f eedi ng i nt o t he muth of ; t he per f or mer,who then spoke vowel s w t h t he f r equenci es suppl i edby t he dri ver i nt o a mcrophone . Al t houghvery eff ecti veon vowel s, t he use of t h i sdevi ce was qui te l i m ted f or

736

Fi g. 11 . Bode f r equency, s h i f t e rmodel 735 Mark I I.

i nt el l i gi bl e speech .

Af t er Dudl ey, Robert Moog was t he f i r s t desi gnerof a vocoder usi ng semconductor t echnol ogy and acti vef i l t e r s. I t was bui l t f o r t he el ec t r oni c musi c st udi o oft he Uni vers i ty of Buf f al o i n 1968 . Af t er that other vo-coders f ol l owed. Those by Sennhei ser and EMS [73],[ 74] became known i n t he l a t e 1970s . I n 1977 t he aut hordevel oped a vocoder that devi ated from t he cl assi calcommuni cat i on- type concept eml oyed by Dudl ey and

others and was ai med toward t he use of di rect per-f ormance ( and ent ert ai nment ) appl i c at i ons ( F i g. 13) .

Thi s mdel f eatures a di rect bypass f or t he consonantf r equenci es s i nce i t was evi dent that onl y t he vowelf r equenci es had t o be encoded and decoded and not t heconsonant s, whi ch di d not have t o change anywayThi s s ys t em whi ch was pat ent ed [75], resul t ed i n ani nst rument of superi or i n t e l l i g i b i l i t y ,presence, and f a s tresponse ( F i g. 14) . Af t er these vocoders a number ofother products i n t h i s category appear ed on t he scene,such as t he Korg, t he El ect r ohar moni x, t he Syntovox,and t he Rol and, al l of whi ch use the convent i onal ap-proach .

3 CLOSI NG REMARKS

I t was t he purpose of t h i s pr esent at i on t o hi ghl i ghtthose devel opment s i n t he f i e l dof el ectr oni c soundmodi f i cat i on that were deemed t o be mst basi c andsi gni fi cant . I t w l l have been obser ved that some of t hepri nci pl es used today can be traced back t o t he veryearl y days of experi ment at i on, and t h a t many of themhave survi ved al l phases of t he technol ogi cal evol ut i on.

4 ACKNOWEDGMENT

The author w s hes t o expr ess hi s appreci ati on t o thosewho have suppor t ed t h i s work . Hi s speci al t hanks got o Dave Luce and Tom Rhea fo r thei r hel p i n provi di ngt he documentati on

Fi g. 12 . Basi c pl ayback confi gurati on of Spri nger devi ce .

Fi g. 13 . Bode vocoder model 7702 w t h 16 anal yzer out putand 16 synthes i zer i nput j acks for c r o s spat chi ng .

J . Audi o Eng Soc . ,Vol . 32, No 10, 1984 Ot ober



PAPERS

Fi e. 14 . Vocoder w t h consonant bypass .

5 REFERENCES

J . Audi o Eng Soc , Vol . 32 . No 10, 1984 October

[1] T Cahi l l , U S . pat ent 520,667 (appl i ed f or i n1895) .

[ 2] T Cahi l l , "The Generat i ng and Di st r i but i ngofMusi c by Means of A C Generat ors , " El ec. Wor l d,p 519 ( 1906) .

[ 3] T Cahi l l , "The Tel harmon um" El ec. Worl d( 1906) .

[ 4] T Cahi l l , "Musi c by El ect r i ci t y, " M Mel i usWorl d' s Week, vol . 12, pp . 7660- 7663 ( 1906 J une) .

[ 5] T Cahi l l , "The Cahi l l Tel harmon um" El ec .

Worl d ( 1906) .

[ 6] "Apparatus f or t he El ect r i c Generat i on andTransm ssi on of Musi c, " Sci . Amer . , vol . 96, pp . 205,210-221 ( 1907 Mar . 9) .

[ 7] W C . Woodl and, "Musi cal Probl em Sol ved byt he Tel harmon um" Sci . Amer . , vol . 96, p . 271 ( 1907Mar . 30) .

[ 8] T Rhea, "The Cahi l l Tel harmon um Part I , "Contemp Keyboard ( El ect roni c Perspect i ves), vol . 3,

p . 47 ( 1977 Feb . ).[ 9] T Rhea, "The Cahi l l Tel harmon um Par t I I , "

Contemp Keyboard ( El ect roni c Perspect i ves), vol . 3,p . 55 ( 1977 Mar . ).

[ 10] E Pet ers on, "The Ri ch Hi story of t he El ect roni cOrgan, " Keyboard, pp 32-36 ( 1983 Nov ) .

[11] O Sal a, "Das neue Mxtur Trautoni um" Mu-s i kl eben, vol . 6, pp 346-348 ( 1953 Oct . ) .

[12] H Gensmer , "Das M xtur Traut oni um" Mu-si kl eben, vol . 7, pp 245-247 (1954 J ul y- Aug . ) .

[13] W Grei ser, "Das M xt urTraut gni um " Musi ca,vol . 12, pp . 307-308 ( 1958 May) .

[14] F Tr aut wei n, "The El ect roni c Menochord, "Tech . Hausmt t . des Nordwest deutschen Rundf unks,

vol . 6 ( 1954) ; t r a n s l . by t he Nat i onal Research Counci lof Canada, Ott awa[ 15] T Rhea, "Haral d Bode' s Four Voi ce Assi gn-

mant Keyboard ( 1937) , " Contemp Keyboard ( El ec-tr oni c Perspecti ves) , p 89 (1979 Dec . ).

[ 16] H Bode, "Bekannte and neue Kl ange durchelektr i sche Musi ki nst r ument e, " Funktech Monat sh . ,no . 5, p . 67 ( 1940) .

[ 17] H Bode, "European El ect roni c Musi c I nstru-ment Desi gn, " J . Audi o Eng Soc , vol . 9, p . 267 ( 1961Oct . ) .

[ 18] "Novachord, " El ect roni cs ( 1939 Nov ) .

[ 191 "Pi anol ess Pi ano: Hammond El ectr i cal No-vachord Myst i f i esMusi ci ans, " Newsweek, vol . 13, p

HSTORY OF ELECTRON C SOUND MOD FI CATI ON

36 (1939 Feb . 20) .

[ 20] "Pi anow t h a Whol e Band i n I t: B . F M essner ' sEl ect roni c Pi ano, " Li t. Di gest, vol . 115, p . 23 ( 1933Mar . 25) .

[21] B . F M essner, "The El ect roni c Pi ano, " ProcMusi c Teachers Natl . Assoc , pp . 259-272 ( 1937) .

[22] B . F M essner, "El ect roni c Pi ano ProducedCommerci al l y, " El ect roni cs (1937 Nov ) .

[ 23] T Rhea, "B . F M essner ' s ' Stri ngl ess Pi ano' , "Contemp Keyboard (Electroni c Perspect i ves), p . 62( 1978 Apr . ) .

[24] I nt ervi ewsof Les Paul by t he author i n t he spri ngof 1981 .

[ 25] M Z Moz, "El ect ri cal Musi cal I nst r ument( El ectr o- Mechani cal Tremol o Ci r cui t ) , " U S . pat ent2 , 245, 354 (1941J une 10) .

[ 26] J . M Haner t , U S . pat ent 2, 509, 923 (appl i edf or i n 1946) (actual l y manufactured system f or pro-duci ng choral t one effect) .

[ 27] J . M Haner t , "El ect roni c Musi cal Apparat us( L - CDel ay L i new t h Var i abl eI nduct ors f or Post SourceVi brato Modul ati on) , " U S . pat ent 2, 382, 413, ( 1 945Aug 14) .

[ 28] J . M Haner t , U S. pat ent 2, 498, 367 (appl i edf or i n 1944) ( p r opos ed s ys t e m f or produci ng choralt one effect) .

[ 29] W C Wayne, J r . , "Audi o Modul ati on System( Choral Tone Modul ator) , " U S . pat ent 3, 004, 460 ( 1961Oct . 17) .

[ 30] D L . Bonham "El ect ri cal Musi c System( Choral Tone Modul ator) , " U S. pat ent 3, 083, 606 ( 1963Apr . 2) .

[ 31] D L . Bonham "Vi bra to Ci rcui t Compri si nga Br i dge Havi ng Non- Li near I mpedance El ements , "U S . pat ent 2 , 988, 706 ( 1961 J une 13) .

[32] H Dudl ey, "System or t he A r t i f i c i a lProduct i onof Vocal and Ot her Sounds ( Voder) , " U S . pat ent

2, 121, 142 (1938 J une 21) .[ 33] H Dudl ey, "The Vocoder, " Bel l Labs . Rec . ,vol . 17, pp 122-126 ( 1939) .

[ 34] H Dudl ey, "The Vocoder, " J . Acoust . Soc .

Am , vol . 11, no 2, p 169 ( 1939) .

[ 35] T Rhea, "Bode' s Mel odi um and Mel ochord, "Cont emp Keyboard ( El ect roni c Perspecti ves), p . 68( 1980 J an . ).

[ 36] H Bode, "The Mel ochord of t he Col ogne Studi of or El ect roni c Musi c, " Tech Hausmt t . des Nord-west deut schen Rundfunks, vol . 6 ( 1954) ; t r a n s l . by t heNat i onal Research Counci l of Canada, Ot tawa

[ 37] H LeCai ne, "El ect roni c Musi c, " Proc . I RE(1956 Apr . ); i ncl udes descri pt i on of Bode Mel ochord

of St udi o f or El ect roni c Musi c at Col ogne .[ 38] W Meyer- Eppl er , "Whi ch Poss ibi l i t i es Exi st

f or t he Meani ngf ul Appl i cat i on of El ect roni c Musi cI nst rument s?" i n Musi cal Acousti cs, Proc . 1st I CA-Congr . El ect ro-Acoust i cs (Del f t , 1953) ; f eat ures t heBode Mel ochord of t he Col ogne El ect roni c Musi c Stu-di o .

[ 39] H F O son and H Bel ar, "El ect roni c Musi cSynt hesi zer, " J . Acoust . Soc Am , vol . 27, pp . 595-612 ( 1955 May) .

[ 40] E T Canby, "Musi c Synt hesi zer (RCA SYN, "Audi o, vol . 40, pp 64- 65 (1956 May) .

[41] M Babbi t , "An I nt roducti on t o t he R . C. A Syn-thes i zer, " Musi c Theory, vol . 8, p 251 ( 1964 w nt e r ) .

737



BODE

[42] H Bode, "El ectr oni c Apparatus (Modul arSound Modi f i cat i onSystem w t h Tape Repeater) , " U S.patent 3, 069, 956 ( 1962) .

[43] H Bode, "The Mul ti pl i er Type Ri ng Modu-l ator, " El ectr on . Musi c Rev , no 1 ( 1967) .

[44] T Oberhei m "A `Ri ng Modul at or' Devi ce f orPerf or m ng Musi ci ans, " present ed at t he 38t h Con-vent i on of t he Audi o Engi neeri ng Soci et y, J . Audi oEng Soc . (Abstracts), vol . 18, p 334 ( 1970 J une) ,prepr i nt 708 .

[45] H Bode, "Sound Synt hesi zer Creat es NewMusi cal Ef f ects, " El ectr oni cs ( 1961 Dec . 1) .

[46] H Bode, "A New Tool f or t he Expl orati on ofUnknown El ectr oni c Musi c I nst rument Per f ormances, "J . Audi o Eng Soc . , vol . 9, p 264 ( 1961 Oct . ).

[ 47] R A . Moog, "Vol tage Cont r ol l ed H gh Pass/Low Pass F i l t e rf or Audi o Si gnal Pr ocessi ng, " present edat t he 17th Conventi on of t he Audi o Engi neeri ng So-ci ety, J . Audi o Eng Soc . (Abstracts) , vol . 13, p 260( 1965 J ul . ) , pr epri nt 413 .

[ 48] "Effects Devi ces Part 2, Vol ume and Wh- WhPedal s, " Cont emp Keyboard, p . 16 ( 1979 Apr . ) .

[ 49] "Effects Devi ces Part 3, Envel ope Fol l ower s,Noi se Gat es and Fuzz Tones, " Cont emp Keyboard,p 22 (1979 J une) .

[ 50] C Ander t on, "For Your Gui t ar, a Compressi onSustai ner, " Pop . El ectr on . , vol . 30, pp 63-64 ( 1969May) .

[ 51] "Effects Devi ces Part 1, Phasers and Fl anger s, "Contemp . Keyboard, p 20 ( 1979 Feb . ).

[ 52] C Ander t on, "Sound Modi f i cati onDevi ces f orKeyboards : An I nt roducti on, " Cont emp Keyboard, p9 ( 1978 July).

[53] B . Bl esser and F F Lee, "An Audi o Del aySystemUsi ngD gi tal Technol ogy, " J . Audi o Eng . Soc. ,vol . 19, pp 393-397 ( 1971 May) .

[ 54] R Factor and S . Katz, "The D gi tal Audi o Del ay

Li ne, " dbMag , p .

18 (1972May) .

[55] F Hi nkl e, "Bucket Br i gade Shi f t Regi st erGenerat es Const ant Phase Del ay, " El ectr oni cs, p . 110( 1964 J u l y 11) .

[ 56] W S . Boyl e and G E . Smth, "Charge Coupl edSemconductor Devi ces, " Bel l Sys . Tech . J . , vol . 49( 1970 Apr . ) .

[ 57] R Buss, "CCD s I mprove Audi o System Per-f ormance and Gener at e Effects," EDN p . 55 ( 1977J an . 5) .

[ 58] B . B a r t l e t t , "A Sci enti f i cExpl anati onof Phasi ng(Fl angi ng) , " J . Audi o Eng . Soc . (Letters to theEdi tor),vol . 18, pp . 674-675 ( 1970 Dec) .

[ 59] L Hammond, "El ectri cal Musi cal I nstr ument

( Coi l Spr i ng Rever berat i on) , "U

S.

patent 2, 230, 836

738

PAPERS

( 1941 Feb 4) .[ 60] D W Mart i n and A F Knobl augh, "Loud-

speaker Accessory f or t he Pr oduct i on of ReverberantSound, " J . Acoust . Soc . Am , vol . 26, pp 676-678(1954 Sept . ) ; coi l spr i ngs mechani cal l y coupl ed w t hspeaker cone

[ 61 ] M R Schroeder, "Natural Soundi ng A r t i f i c i a lRever ber ati on, " J . Audi o Eng Soc . , vol . 10, p 219(1962 J ul y) .

[ 62] M R Schr oeder and B . F Logan, "Col or l essArt i f ic ia l Rever ber ati on, " J . Audi o Eng Soc . , vol . 9,p 192 ( 1961 July) .

[ 63] J . M Chowni ng, "The Si mul ati on of Movi ngSound Sources, " J . Audi o Eng . Soc . , vol . 19, pp . 2-6 ( 1971 J an . ) .

[ 64] D W Mart i n, "Monaur al - Bi naur al Transms-si on of Sound f or Produci ng a Haas e f f e c t , "U S . patent2, 879, 683 ( 1959 Mar . 31) .

[ 65] L . Heck and F Buerck, "Kl angumormungeni n der Rundf unkst udi otechni k, i nsbesondere durchAnwendung der Frequenzumetzung, " El ektr on .

Rundsch . , p 1 ( 1956 J an. ) .

[ 66] H Bode, "Sol i dState Audi o Frequency Spec-trum Shi f t er, " presented at t he 17t h Convent i on of t heAudi o Engi neer i ng Soci et y, J . Audi o Eng Soc (Ab-s t r a c t s ) , vol . 14, p . 66 (1966 J an. ) , pr epr i nt 395

[ 67] T Rhea, "Haral d Bode' s Frequency Shi f tersand Vocoders, " Cont emp . Keyboard (El ectroni c Per-specti ves), p 86 ( 1980 Feb . ) .

[ 68] H Bode, "Frequency Shi f ters f or Pr ofessi on-al s, " db Mag . (1976 Mar . ).

[ 69] H Bode and R A Moog, "A H gh- AccuracyFr equency Shi f ter f or Prof essi onal Audi o Appl i cati ons, "J . Audi o Eng . Soc . , vol . 20, pp 453-458 ( 1972 July/Aug . ) .

[ 70] H Bode, "Apparat us f or Produci ng Speci alAudi o Effects Uti l i z ingPhase Shi ft i ngTechni ques ( BFO

Fr equencyShi ft er), " U S. patent 3, 800, 088 ( 1974 Mar .

26) .

[ 7 1 ] H Bode, "Mul t i phase Si gnal Osci l l ator ( Quad-rature Osci l l ator f or Frequency Shifter)," U S . patent4, 145, 670 (1979 Mar . 20) .

[ 72] C Andert on, Gui tar Gadgets ( Amco Publ i -cati ons, 1983) , chap 6, p 98 .

[ 73] N Condron and H Ford, "EM Vocoder , "Studi o Sound, p . 98 ( 1977 J ul y).

[ 74] B . Moog, "Vocal Sounds, Part I I: Vocoder s, "Cont emp Keyboard (On Synt hesi zer s) , p . 54 ( 1978May) .

[ 75] H Bode, "Anal og Speech Encoder and Decoder(Bode Vocoder) , " U . S . patent 4, 158, 751 ( 1979 J une

19).

J . Audi o Eng Soc .,Vol . 32, No . 10, 1984 Oct ober



PA"ERS

Haral d Bode, a graduat e of t he Uni versi t y of Hamburg, Ger many, and a post graduat e of t he Techni calUni versi ty of Berl i n ( Hei nri ch Hert z I n s t i t u t e ) ,becama c t i v ei n el ectroni c musi c i nst rument desi gn i n t he m d-30s . H s creat i ons i ncl ude the War bo For mant organ( 1937) , t he Mel odi um 1938) , t he Mel ochord ( 1947-1953) , mst w del y known t hrough t he wor k of Stock-hausen at Col ogne, West Germany Further i nst rument si ncl ude t he Pol ychord ( 1949), t he Bode organ ( 1951-l ater known as t he Estey el ectroni c organ), t heconcert

mdel of t he Cl aviol i ne ( 1953) , and a mdul ar syn-t hesi zer/ sound processor ( 1959-1960) . The Bode r i ngmodul at or s and f r equency shi f ters ( 1961) are f ound i nmany Amri can and f orei gn studi os . The Bode Vocoder ,devi at i ng from convent i onal concept s, was created i n1977

Bode hol ds mre t han 50 US and f orei gn pat ent s .

He served as AES sessi on chai rman f or musi c andel ectroni cs i n 1962 and 1964 He i s t he head of t heBode Sound Company of Nort h Tonawanda, New York .

J . Audio Eng Soc . Vol . 32, No . 10, 1984 October

H STORY OF ELECTRONI C SOUND MOD FI CATI ON

73 9 .



Li st of Tape Recordi ngs for MAC 81 by Haral d Bode

1 . - Trautcni um advanced model , 1961 recordi ng(Rem Gassmann' s Musi c to the Bal l et , as produced byThe rew . York C ty Bal l et Company under the di rect i onof George Bal anchi ne) .

2 . - Hammond rovachord, Tea f or Two, pl ayed by Fred Fei bel .

3 . - Homer Dudl ey Vocoder, 3 segments .

4 . - Dual Fcrmants of Mel cchord, Hamburg (1949)

Sound- on- Sound w th Mel ochord Hamburg

F . - Travel l i ng Formant a l a mel echord Col ogne (earl y 50' s)

a - vl angi ng w th whi te noi se .

11 . - Moog 12-st age nhaser w f eedback,

10 . - Marshal l Ti me Modul atora) Radi cal ti me compressi on ; Bi l l y Thorne : Chi l dren cf theh) Mul t i t rack mul ti _ol o uses of t i me modul ator ;

(Pl ati num record) Stevi e : < cnder : Ebony Eyes .

c) Resonant f l ange ; J ohn McLaughl i n : Phenonenoni Compul si ond) Pi tch quanti si ng,P) Fcho, Pi tch shi f t .

12 . - Bode Frequency shi f ter : a) Bel l sounds through exp controlh) spi ral i ng echo 3 sampl es .

c) Percussi on f ol l ower f or pi tchchange on drum .

13 . - Samnl e/ Hol d used on vol tage control l ed f i l ter .

14 . - Moog stri ng fi l ter .

15 . - "Poor man' s Vocoder" ( the "bag") .

16 . - Bode Vocoder : a) Vl al ter Cronki te si ngi ng the news, ( ~ , ~: x t b ) Funkvtcwn, , ~c) D scover Magazi ne, d) Atari .

17 . - I nf i ni te phasi ng on Barberpol e PhaserTMa) Pi nk noi se phased up, b) Chord on Pol ymoog phased upc) Phasi ng w th step f uncti on on chord sequence, '

d) Compl ex phasi ng pattern on Bass gui tar .

11, - EXMA : . (' c4WU i TP d' y., r c~2ul J ~c~Trf~4u~vc b' ~P. vgs~~" ( o Mu UTE I -)EC&

7 . - RCA Synthesi zer (1955)

P. - Modul ar Sound Modi f i er a) ki ng Modul ator,(1959/ 60) 1b) A-B Echo,

c) Percussi on Fol l ower,d) Voi ce tri ggered mel ody generator,e) Pi tch Extractor w octave coupl er,



( " eal , ~ kz

Oa- ah̀L `

a, 44 Op Ta , c k - l )"

.

U

~ Lk~~ L L

L~

~~~ u~1cz 1 -

00 Ou . . .. , , ~: i v~

0

Nv ~ i- -

UO ( N' , v ~t i G: e~ b, r

i

An--r~ o i , - SC)COV OX

)) J ~- ,N~ , 4) Ll r c"

v ,&L. ct 1Q(, rx_~ l t~ a . Y

L7

_

-- o Fl f F4 ' J '



RC C

RE, ( w S

2cc ~

Rcc~ 7

cC~ 8

R A to

PE(A11

e C, ~s l ' 4 c̀ c& , ~ MAC ~1

/ I J <L_ 2 2 4) .

r ~r

~N

l 4 ML4k~

v .

3y 0 - PI Gr, Goce-A sor r v - i

3S

Z

vG

~Dq V

3~a

4

Ij i s

v

r ,

u

, P4, , , , cmc /

2t , r ~ p~C t s

~7 rj l 0u~c- ti , t i r . z. ~e~

/11

110

J

0

~%

11c e r t K

[/~ /~

/ / u v <

15



I NTRODUCTI ON

H STORY OF ELECTRON C SOUND MOD FI CATI ON

by Haral d Bode

The hi story of el ectroni c sound mdi f i cati on i s as ol d as the

hi story of el ectroni c musi cal i nstrumnts and el ectroni c sound

transmssi on, recordi ng and reproducti on .

Means f or modi f yi ng el ectr i cal l y generated sound have been known

si nce the l ate 19th century, when Thaddeus Cahi l l created hi s

Tel harmni um

Wth the advent of the el ectroni c age, spurred f i rst by the

i nventi on of the el ectron tube and i n the mre recent decades through

the devel opmnt of sol i d state devi ces, an astoundi ng vari ety of sound

modi f i ers has been created f or f i l teri ng, di storti ng, equal i zi ng,

ampl i tude and f requency mdul ati on, doppl er ef f ect and ri ng

mdul ati on, compressi ng, rever-berati ng, repeati ng, f l angi ng, phasi ng,

pi tch changi ng, chorusi ng, f requency shi f ti ng, anal yzi ng and re-

synthesi zi ng natural and arti f i ci al sounds .

I am now goi ng to gi ve a revi ew of som of the hi ghl i ghts of the

hi stori cal devel opmnts, wth sl i des coveri ng the hi story f rom 1896 to

the present, and wth tape recordi ng=_ coveri ng a ti m span of mre

than 40 years of sounb mdi f i er devel opmnts .



I n order to gi ve a most compl ete account on the hi story

of el ectroni c sound modi f i cat i on, i t w l l be i mport ant to i ncl ude

the t i me span, whi ch preceded the purel y el ectroni c era, and al so

to i ncl ude some port i ons of the hi story of el ect roni c ( and el ectri -

cal ) i nst ruments, i n whi ch the means f or sound modi f i cat i on

f ormed an i ntegral part of the whol e system

cl as si cal case i n poi nt i s the "Tel harmoni um by Thaddeus

Cahi l l , whi ch was bui l t around 1897, Thi s i nstrument used the

pri nci pl e of addi t i ve tone synthesi s f or sound mani pul at i on and "

modi f i cat i on . The i ndi vi dual tone col ors were bui l t up f rom, ,

. 1f undamental s and overtones, generated i n huge dynamos ; and f or

the nurnose of aenerati nf f Dure si ne waves f or thi s synthesi s, the

i ndi vi dual crPnerator - coi l s were tuned w th capaci tors, another

nears f or sound modi f i cat i on . . . ,

"' t er the - el harTonJ " - , xre +speci al l y aOter t he i nvent i on

of the vacuum tub e, scores of el ect roni c musi c i nstruments were

i nvented w th more or l ess outstandi ng f eatures f or sound modi -

f i cat i on, nmonci these was the Trautoni um whi ch extensi vel y usedresonance f i l ters, : t o emphasi ze sel ecti ve overtone regi ons, cal l ed

f ormants,



M R2

I n contrast, the German J 6rg Mager bui l t an organ l i ke

i nst rument i n the earl y 30' s, f or whi ch he used l oudspeakers of

al l ki nds and shapes to obtai n di f f erent sounds .

Cahi l l formed the f oundati onhe ori gi nal work

ofThaddeus

for the devel opment of the Hammo nd

scone i n the earl y 30' s . Many notabl e i nvent i ons i n the f i el d

organ, whi ch appeared on the

of el ect roni c sound modi f i cat i on are connected w t h t hi s i ns tru-

ment, whi ch wl l be di scussed l ater .

I n 1937 I created the warbo Formant organ, whi ch had ci rcui tr y

type i nstruments . 1Z

A very i nterest i ng means for

modi f i ed by changi ng the

t i ve) al ong the st ri ng s. For i nstance,

t i ons i n the center, al l odd harmoni cs

of the l ength of the str i ng, the thi rd,

for envel ope shapi n g of the tones as wel l as f i l t ers of hi gher

c cmpl Pxi ty than those used bef ore . I t had two sets of f i l t ers and

a voi ce assi cTnment keyboard, through whi ch, for i nstance voi ces

1 and 3 coul d be assi gned t o the f i rst f i l ter and voi ces 2 and 4

to the second f i l ter . By maki ng the pass regi ons of t he f i l t er s

c ompl ementar y, c ompl ement ary tone col ors coul d be produced, whi ch

sounded very pl easi ng to the Far .

I n the l ate 30' s al so the Hammond Vovachord was created,

whi ch agai n made use of f ormant f i l ters for overtone modi f i ca ti on

and means for envel ope shani ng to produce tones of wnd and

sound modi f i cat i on i s found

i n the Fl ectro6hord by (`scar Vi erl i ng and the Messner pi ano .

st ri ng

i t was found, that the tonal qual i t i es coul d be dramati cal l y

l ocat i on of pi ckup s ( i n thi s case capaci -

when pi cki ng up the osci l l a-

woul d appear . At one thi rd

si xth and so fort h



harmoni c woul d be cancel l ed, and pi ckup poi nts at other l ocati ons

of the stri ng l ength woul d produce correspondi ng resul ts .

The rl ctrochord as wel l as the Messner pi ano were bui l t

w thout soundi ng boards, si nce these di d no t a nym o re se r v e any

usef ul purpose . The same was true for the LPs Paul gui tar , and

i t mght be i nteresti ng to l earn, that Les Paul i nvented the

sol i d body gui tar as f ar back as i n 1927 . . .. i n hi s earl y experi -

ment s Les Paul used the magnet s of the ol d day type headphones,

whi ch used steel di aphragm as membranes . The G bson Gui tar started

i n 1941 , and i t has ever si nce been associ ated wth an i ncredi bl e

number and vari ety of sound modi f i cat i on devi ces and metho ds,

some of whi ch wl l be di scussed i n more detai l .V

From the very begi nni ng one very i mportan t means of sound

modi f i cati on has been the tremol o and the vi brato, the tremol o

bei ng an ampl i tude modul at i on and the vi brato a f requency modul a-

ti on .

i t i svery i nteresti ng to note, that

post source f requency

modul ati on i ni ti al l y- nosPd a probl em and that the f i r st Hammon d

organs i n the earl y 30' s were equi pped wth means f or ampl i tude

modul ati on or tre mol o .

At a l ater ti me, that was i n th e md 40' s, a del ay l i ne

wth vari abl e i nductors was i nvented by Hanert, and a di f f erent

tyre of vari abl e d el ay . l i ne w th _a _ . _ .number of . . del ay taps and a

.

cana ci ti ve scanner was i ncorporated i n the Hammond organ . By

combi ni ng the f requency modul ated si gnal w th the di rect si gnal ,

al so a type of choral tone ef f ect coul d be produced and t he,

f ound a ti on was l a i d f or todays f l ang er s .



SZ- ~

S~ " S

A tremendous step f orward i n t he f i el d of sound modi f i cati on

devi ces was taken by Homer Du d l ey, by hi s creati on of the Voder

and the Vocoder i n the l ate 30' s .

The Voder was a keyboard operated i nstrument control l i ng

a number of bandnass channel s f or si mul ati ng the resonances of

a speaker . Wth the addi ti on of a tone source, al so cal l ed the

buzz source and a noi se source, al so cal l ed the hi ss source,

vowel s and consonants of the speaker coul d be i mtatedbe ; n- as Ear- Caw r

.he systembecame even more exci ti ng, when the Voder/ was

Decanter

combi ned w th apt FRreeAwr, and thi s combi nati on bei ng cal l ed the

vocoder, whi ch compri sed an anal yzer f or anal yzi ng the speech and

a synthesi zer f or remaki ng the same speech

Fcr accompl i shi ng thi s, the audi o range was sl i ced up i nto

a number of bandnass channel s i n the anal yzer, whi ch correspond

to an equal number of bandpass channel s i n the synthesi zer . I n

each anal yzer channel a control vol tage was generated i n what

we now cal l an envel ope f ol l ower, whi ch was then fed to the

control vol tage i nnut of a vol tage control l ed ampl i f i er i n the

corresocndi nd synthesi zer channel . 12

By l i steni ng to the recordi ngs of the Dudl ey Vccoder, i t

w l l be observed, , that not onl y the speech art i cul ati on i s bei ng

remade but al so the speech i nf l ecti on, whi ch cl earl y i ndi cates

the presence of a pi tch extractor - that worked - as wel l as

a pi tch- to- vol tage converter and a vol tage control l ed osci l l ator . -

I n the cl osi ng porti on of today' s presentati on I am goi ng to

deal w th a f ew more aspects, modi f i cati ons and appl i cati ons

of the 17 ocoder .



1R4

Y ) 7 / , ? S

RCD

n 7

S, U

Thus f ar we have observed, that one i mportant el ement i n

sound modi f i cat i on devi ces i s represented by a vari ety of f i l ters,

such as the f ormant f i l ters of the Trautoni um and the Hammond

Novachord, the compl ementary tone fi l ters of the Warbo Formant

organ and the band pass f i l ters of the Vocoder . Another i nstrument

wth strong f ormant f i l ters was the Bode Mel ochord, whi ch was

bui l t f or several maj or broadcast stat i ons i n t i 7es f Germany by the

l ate 40' s and the earl y 50' s . The Mel ochord was al so equi pped

wth ci rcui t ry f or t he cont rol of at tack and decay envel opes,

vi brato and the capabi l i ty to pl ay t ravel l i ng f ormants, the f re-

quencyuency of whi ch was keyboard control l ed .,

I n the Mel ochord f or t he

Stockhausen Studi o i n Col ogne the modul ar concept was adopted,

by whi ch external ri ng mcdul ators, echo chambers and thq l i ke

coul d be i ncl uded i n the syst em

J ust f or the compl et i on of the record , I shoul d menti on,

that around the same t i me I created the Bode organ, l ater known

as the Rst ey el ect ron i c crgar of the 50' s, whi ch used the pri n

ci ol e of harmoni c tone synthesi s . Si nce i t was, unl i ke the Hammond,

pure1Y el ectroni c, i t di d not need means f or post source vi brato

modul at i on . I nstead i t used synchroni zed Hart l ey osci l l ators wth

f requency modul at i on of the master st ages .

A uni que i nst rument combi ni ng many of the means of tonev

generat i on and sound modi f i cat i on known at that t i me was the

RCP synthesi zer, whi ch was created under Harry F . O son and made

i ts debut i n 1955 . The PCA synthesi zer was (and i s) cont rol l ed

by preprogrammed punched tape I t has such f eatures as di gi tal l y

cont rol l ed f i l ters, cont rol of at tack and decay envel opes, di gi -



tal l y control l ed pi tch and waveshapes, random noi se generati on and

f requency and ampl i tude modul ati on .

Around the same ti me Les Paul became famous w th hi s mul ti -

track gui tar recordi ngs, al so usi ng tape speed transposi ti on and1 1

the repeti ti on ef f ect . The wel l known pi ese " V~i. speri ng" was done

i n the earl y 50' s . Besi des bei ng an outst andi ng performer, Les

Paul was and i s al so an outstandi ng i nnovator . I t was Paul who

i ntroduced the mul ti track recorder (8- track on 1 i nch tape) i nHe O!SO J i tMOOLkceot~

cooperati on w th Ampex . &ew - 1 a ( ' t he` Sel Sync . Hi s repeti ti on

to have a tape, repeater . Thi s modi f i er al so had a number of

modul es, one of -whi ch was a ri ng modul ator .

Thi s, at the' ;- t i me, was a rel ati vel y l i t t l e known sound modi -

f i cati on devi ce, mai nl y known f rom si ngl e si deband communi cat i on

system . The mai n reason was, that up to the md or l ate 50 ' s

ef f ect was done w th a 5 head recorder . Hi s tape speeds were

i ni t i al l y 60 and 30 i ps and l ater reduced to 30 and 15 i ps . I t

was Paul who created the I RR F: curve .

Pri or t o the tape era Paul created the repeti ti on ef fect on

16" di scs w th 5 pl ayback pi ckups bei ng i n the same groove w th

the cutti ng head, Thi s was i n 1941 .

Les Paul , of course, st i mul ated many i nnovators and duo to

hi s success encouraged them to work i n the fi el d cf new sound

ef f ects . Hi s i nf l uence i n many areas i s fel t to thi s day .

I personal l y was so i mpressed by hi s work, that I l ater

started work on a sound modi f i cati on system whi ch natural l y had J



S '

J

thi s devi ce was a swtchi ng ci rcui t , whi ch sounded too harsh to

be usabl e f or sound modi f i cat i on . onl y af ter ri ng modul ators

were bui l t , whi ch operated i n the square l aw regi on of thei r

t ransf er f unct i on (whi ch was the case w th certai n Germani um

di odes) , they started to perf orm as f our quadrant mul t i pl i ers

and became musi cal l y i nteresti ng

Late i n 1959 through the begi nni ng of 1960 I bui l t a modul ar

sound processor, i n whi ch I used these r i ng modul ators and other

sound modi f yi ng devi ces, such as an envel ope f ol l ower, a tone

burst control l ed envel ope generator, a vol tage control l ed

ampl i f i er, f ormant and other f i l ters, mxers, a pi tch extractor,

a comnarator and f requency di vi der f or t he extracted pi tch, and

a tape l oop repeater wth dual channel processi ng

The modul ar concept proved i nteresti ng and usef ul , and i t was

adopted by ncb Moog, when he created hi s modul ar synthesi zer, whi ch

was i ntroduced i n' 1964 Thi s synthesi zer i ncl uded a vari ety of

sound modi f i cA on devi ces and syst em modul es such as vol tage

control l ed f i l ters, envel ope venerators,

vol tage control l ed ampl i f i ers, and sampl e/ hol d ci rcui t s . At a

l ater date al so Bode ri ng modul ators and Bode f requency shi f ters

were added to the Moog l i ne 20c

FS



that i s cn the market .

By the md to l ate 60' s sound ef f ect devi ces such as the

Pl ahwah f ound thei r entry i nto the popul ar entertai nment musi c ,

f i el d, Accordi ng to i nf ormati on made avai l abl e to me the f i r st

successf ul Wahwah was the "Cry Baby", whi ch ori gi nated i n Engl and

around 1965, I t st i l l worked w th Germani um t ransi stors . A very

ef f ect i ve Wahwah was, of course, the Moog vol tage cont rol l ed

l ow Dass f i l ter capabl e of very pronounced resoonances, whi ch. 1 , 4 j I A," -9% w, #~~

coul d be act uated by a control vol tage pedal , ; - -u YdI 5rstan d hat

the "Mutron", an automat i c Tti ' ahwah, - the successf ul sound modi f i er

of thi s ki nd ted a ,

Another popul ar sound ef f ect devi ce, whi ch started i n the

md 60' s, i s i n the category ef _ the so cal l ed Fuzz Boxes, The

story goes, that the Fuzz start ed w th J ef f Beck maki ng . a gui tar

recordi ng by overdri vi ng a def i ci ent preampl i f i er of hi s tape

recorder .

The fi rst successf ul f uzzboxes i ncl ude the VCX D stort i on

Bc oster, whi ch ol ugs i nto a gui tar, and whi ch ori gi nated i n

rncTl and i n 1964 . At around the same t i me the bat tery operated

Arbi ter Fuzz Face anneared on the scene .

There are, of course, qui te a number of other wahwahs and'a 4

fuzz boxes anq other sound ef f ect devi ces on the market , whi ch4 .,cL

- l aawe/ not menti oned, I s-i nce-i t--i sf the mai n purpose of t r i - ai s

~pres~a- t i enl to t race back the hi story of el ectroni c sound modi -

f i cati on rather than to _gi ve a catal og l i sti ng of everythi ng



Further el Pctroni c sound modi f i cati on devi ces that have

been successf ul to thi s date, are i n the category of f l angers and

phasers, and i t wl l be of i nterest to trace back the hi story of

thei r di scovery and thei r desi gn .

The f l anai nq ef f ect can be commonl y observed outdoors, when

a j et fl i es overhead, and the di rect sound . and the sound ref l ectedresul ti ng i n

f rom the ground are summed i n the ear of the observer, ) OaMd as~cxx

the cancel l ati on of certai n f requenci es and produci ng the comb

fi l ter ef f ect, most commonl y al so ref erred to as the "J etsound" . ec

I n the hi story of recordi ngs the story goes, that wth the

i ntent to produce dnubl e tracki nq wth 2 recorders wth sl i ghtl y

di f f erent V sneeds or the ni ece "The Bi g Hurt" the f l angi ng ef f ect

was produced acci dental l y .

Les Paul produced the f l angi ng ef f ect i n "b ames Doogi e"

wth 2 di sc recorders, of whi ch one had vari abl e speed control (1945)

At a l ater ti me, wth the avai l abi l i ty of tape recorders, f l angi ng

was produced w th 2 , - tare recorders, one of whi ch had vari abl e

speed control .A f amous reccrdi na made thi s way was "I tchycoo

Park" by Smal l Faces around the l ate 60' s .

Af ter the theory of f l angi ng had been establ i shed for some

ti me and the i ndustry was onl y w&a wai ti ng f or usabl e i ntegrated

ci rcui ts to make del ay l i nesof suf f i ci ent qual i ty and del ay ti me,

Ri chard Factor of , Eventi de fi rst demonstrated el ectroni c f l angi ng

wth a practi cal l y "conti nuousl y" vari abl e D gi tal Del ay l i ne at

the AES Spri ng conventi on i n 1973 . Pri or to that ' Eventi de had been

exneri menti nq wth BBD s for several years .



The Eventi de I nstant Fl anger was i ntroduced i n the Spri ng

fi rst usabl e transposi ng devi ce .

of 1975 . I t was l ater f ol l owed by the Pi tch Change Modul e f or the

1745M DDL and then by the Model H910 Harmoni zer, whi ch was the

I n contrast to the work of Factor of Eventi de Steven St .

Croi x of Marshal l El ectroni c concentrated on the f l exi bi l i ti es of

a modul ated anal og del ay l i ne, whi ch i s cal l ed the Ti me Modul ator,

and for whi ch new anal og del ay I C s were devel oped . Wth thi s Ti mev-ZVZ- , Cn, ~~n . cuL

Modul ator a l arge vari ety of Ef f ects . can- - - be, <PTodddAd, such as

Automati c Doubl e Tracki ng, Automati c Tri pl e Tracki ng, Negati ve

Fl ange, Posi ti ve Fl ange, Resonant Fl ange, negati ve Ki l l er Fl ange,

Posi ti ve Ki l l er Fl ange, Vi brato, Arpeggi o, Pi tch Quanti si ng,

2 Drum Sl ans, Reverb w th Detune and others . The Parshal l Ti me

Modul ator was i ntroduced to the trade i n 1976 . R/ t 7 ~~ .

General l y speaki ng, i n Fl angers a comb f i l ter ef f ect i s

produced, where the snaci nq of the peaks and notches equal s the

reci procal of the del ay ti me I n contrast, i n Phasers, dependi ng

upon the desi gn parameters used f or the phase fi l ter, the spaci ng

of the peaks or notches can be made to cover equal musi cal i nter-

val s . A l pass phase fi l ters have been known f or anal og computers

roughl y si nce the 40' s . So basi cal l y the technol ogy woul d haver

been avai l abl e to bui l d phasers atthat ti me Accordi ng to one

report the f i rst ' User of nhasers was Dodi e Fi el ds i n the md 50' s .

The Countryman Phase shi f ter became known i n the earl y 70' s .

Another successf ul phaser of the earl y ti mes i s the Maestro , Phaser,

whi ch was desi gned by Tom Cberhei m



I~O

Another l arge number of phasers of al l ki nds of si zes and

pri ce ranges have appeared on the market, and I l i ke to menti on

/ f the Moog 12 staqe Phaser, on whi ch the number of phasi ng st ages

as wel l as the number of st ages i ncl uded i n the f eedback l oop

can be sel ected . k1l

A very i mportant i ngredi ent i n sound modi f i cati on i s the

addi ti on of reverberati on to the program materi al . I n the ol d days,

that i s i n the 30"

s, one used echo chambers f or thi s purpose, and

w th very good resul ts . But they were expensi ve and space con-

sumng Then, i n 1941 came the i nventi on of the Hammond spri ngreverberati on, whi ch was i ncorpcrated i n hi s organ tone cabi net,

but whi ch al so i s very usef ul i n studi os, and the cf f spri ngs of

whi ch are st i l l copul ar . Another way to successf ul l y prcduce rever-

berati on ef f ects i s, of course w th tape repeaters . Af ter the advent

of usef ul del ay l i nes arti f i ci al reverberati on became f easi bl e

w th tanned del ay l i nes . Schroeder of Bel l Labs proposed a system

T 1 9 f or Natural Soundi ng _Reverberati on, i ncorporat i ng a number of

del ay l i nes and f eedback conf i aurati cns . The most successf ul

reverb devi ce st i l l i n use today was the EMT pl ate reverberati on

devi ce

As i t was menti oned bef ore, post source f requency modul ati onl

i s very i mportant to enhance certai n program materi al s . The most

f amous devi ce to " ; produce Doppl er vi brato by rotati ng speakers was

and i s the Lesl i e tone cabi net .

The f i rst el ectroni c phase shi f t vi brato was i ntroduced by

Don Bonham i n 1958 .



~~12 YS 7

Another st i l l rel ati vel y l i t t l e known type of sound modi -

f i cati on devi ces are f requency shi f ters, al though they are capabl e

of produci ng qui te startl i ng ef f ects . The f i rst f requency shi f ters

were i ntroduced by Heck and Btrck i n the 50' s i n Germany . They

operated on the pri nci pl e of heterodyni ng the program matei i al

f or i nstance through a 20 kHz carri er i nto a hi gher f requency

range, pass one of the si debands thus produced, through a si ngl e

si deband f i l t er ( f or i nst ance passi ng 20 to 30 kHz) and to re-

heterodyne these f requenci es back i nto the audi o range w th a

carri er that devi ated f rom the 20 kHz by the amount of f requency

shi f t ul ti matel y desi red .

A di f f erent vari ety of f requency shi f ters now successf ul l y

i n use, operates on the phase shi f ter and mul ti pl i er pri nci pl e .

A di al phase shi f ti ng network modi f i es the program si gnal to produce

output si gnal s, whi ch are i n 90o phase rel at i onshi p rel ati ve to each

other over a f requency range f rom 20 Hz to 20 kHz . These f eed i nto

the f i r st i nouts of - 2- mul ti pl i ers . A quadrature osci l l ator produces

si ne/ cosi ne rel ated shi f t f requenci es, that are f ed to the second

i nputs of the 2 mul ti pl i ers . The mul ti pl i er output si gnal s are those

of ri ng modul ators . Due to the phase rel at i onshi ps of the 2 output

si gnal s a f requency shi f ted si gnal i s produced when summng ther

2mul ti pl i er outputs . /

Frequency shi f ters can be used f or a vari ety of i nteresti ng

ef f ects i ncl udi ng the spi ral i ng echo ef f ect . I n cooperati on wth

Bob PToog a f requency shi f ter was created i n 1973, whi ch has an



S 60

S G 7r

R y

exponenti al control vol tage- to f requency shi f t i nterf ace, so i t i s

keyboard compati bl e ' ~? ,12

A di f f erent category of sound modi f yi ng devi ces i s that

of detuni ng devi ces . I al ready ment i oned the Harmoni zer by eventi de,

whi ch nowhas i ts compani ons by Lexi con, Pr- ,R and others . The basi c

pri nci pl e of these detuni ng devi ces was proven i n the Spri ngeri M -~-' ~- C 4 4 G' s Z

devi ce a mac}i nP" -wth mul t i pl e rotat i ng tape heads, whi ch i s

attached to a st andard tape recorder . Another devi ce i n the el ectro-

mechani cal category i s a ci rcul ar 12 capst an devi ce to change the

tape speed wthi n the 12 st eps of the tempered scal e ( PnQ~~~ ' ~»e)

The pi tch t ransposi ng i dea f i rst executed by Spri nger has

st ayed the same i n todays el ectroni c transposi ng devi ces, and the

basi c concept i s that of si Ktax sl i ci ng up the program materi al i nto

S.

(0 3 seri es of spl i ces of suf f i ci ent l y short durati on and to compress

er to expand these sl i ces bef ore recombi ni ng them

As menti oned before, fi l teri ng represents a very basi c

met hod of sound modi f- i cati on . A uni que type of fi l ters, that i s

worth menti oni ng, i s the str i ng fi l ter by Moog compri si ng 4 groups

of 9 very sel ecti ve fi l ters, whi ch can be acti vated i n di f f erent

conf i gurat i ons for i nteresti ng tone col ori ngs, i ncl udi ng those . of

stri ngs . When al l fi l ters are acti vated, a total of 36 resonators_ f

cover the performance range .Fi nal l y, i n' cl osi ng, I want to devote a f ew mnutes to the

Vocoders of the present .

vV c , C ~CaW - v, e ( t~r A k%a , 4 : Z 1 .-A h PLE HO 4 J , 7l co4y

S

~~~, ~~ J ! J / ?

oa r ,

r QL c r r



S

; ~. ~. o v - a - X 192- 9

An i nteresti ng, devi ce, whi ch preceded t oday' s modern Vocoders,

was cal l ed "The Bag" ; wt h t he nam of Bob Hei l associ at ed wt h i t .

I al so n cknamd i t "The poor man' s vocoder . I t consi st ed of a

sneaker dr i ver syst em wt h a vi nal t ube f r om th s dr i ver f eedi ng

i nto the mout h of t he per f ormr, who t hen si nce vowel s wt h t he

f r equenci es f rom t he dr i ver i nto a mcrophone . A t hough very ef f ect i ve

on vowel s, t he use of t hi s devi ce was l i mted f or i nt el l i gi bl e speech

I nci dental l y, I exper i mnt ed wt h a si ml ar devi ce i n t he l ate 40' s- {- T exk st &, v7ci n j ~t r - - C1 .?-a e a, . - / ? , , j b roVOk i i l - 1~29 ~ZAP4O

Af t er Dudl ey Rober t Moog was t he f i rst desi gner of a vocoder

wt h semconductor t echnol ogy and acti ve f i l ters, whi ch was bui l tf or t he el ect roni c musi c studi o of the Uni ver si t y of Buf f al o i n

1858 . Af t er t hat ot her vocoder s f ol l owed by Fennhei ser and FMS,

whi ch becam known i n t he l at ter har t of the 70' s . I n 1°77 I

devel oned a vocndpr of t he di rect Per f ormance t ype wt h a di r ect

bypass of t he consonant f requenci es, si nce i t was evi dent , that

nnl y t he vowel f r equenci es had to be encoded and decoded and not

t he consonant f requenci es, whi ch di d net have to change anyway .

Thi s syst em whi ch was nat ent ed, r esul t ed i n an i nst rumnt ofand presence &~ «78~

sueer i or i nt el l i ni bi l i t y/ and f ast r esponse . The Moog vocoder was

- ~t g bui l t under the sam patent . Af ter my vocoder a number of ot her

. SG 9 vncoders anapared on t he scone, such as t he Korg, t he R ect rohar -

S v mnn x, t he Synt wox and the Rol and, whi ch use t he convent i onal

svst pm annroach

C osi ng rpmarks s Th s concl udes my present at i on of t oday on the

hi story of el ect ron c sound modi f i cat i on . D` i m+t - e' , t i me10 -

avai l abl e I was onl y abl e t o t ouch t he t i p of t he i ceberg, but I

hope, t hat I have been abl e t he expose som i nt erest i ng hi dden

Documents

Harald Bode - History of Electronic Sound Modification