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LeafVocoder Questions
by Kurt B. Reighley
Editor, CMJ New Music Monthly


Kurt's Questions (received via e-mail) with Wendy's replies:

Question #1 -- What attracted you initially to the vocoder? What what it about the timbre/application/etc. of this device that made you want to utilize it in your work?

Reading about it in tech journals. It seemed like magic! Then I got a chance to try one at the NY World's Fair of 1964-65, at the Bell Labs pavilion. I was hooked! When I figured how to make it not just speak, but sing, it earned an assured place in a forthcoming new album. You know, it seemed an exciting idea to share! The first reactions were unanimous: everyone hated it! A playing synth was bad enough, but a "singing" synth? Too much, turn it off! Thus Timesteps was born, to "ease into" the first experience most folks would have with a "singing machine"... All to easy to forget this history now.

Question #2 -- Was the music for "Clockwork Orange" the earliest work in your canon to use the vocoder? Regardless, why did you feel the device was ideally suited for this specific project?

Yes, but the main vocoded portions were done BEFORE getting assigned to do the film, for the last mvmt of Beeth Symph #9, and Timesteps, nearly a year before working with Kubrick. The Ninth, m. IV, has a singing chorus -- so the suggestion to use a vocoder was automatically made by choosing to realize the piece. At that time it was all unexplored territory, we were the first audacious (or just plain silly) enough to attempt this. Many have followed, of course.

Question #3 -- Do you have any feelings, pro or con, about the pop culture baggage that's been attached to the sound of the vocoder as a result of some of the more popular, albeit arguably pretentious, uses of it in pop music? (I'm thinking about folks like Alan Parsons Project and Styx, not Kraftwerk or Laurie Anderson.)

Not especially. Most pop stuff is done for commerce these days, isn't it, not any real artistic motive nor curiosity? They try whatever stands the best probability to make money. Simple. I'm not too excited to observe that, nor repeating what's been done very well already, so the topic isn't at all interesting. Just the use of a vocoder does not prove a connection more than trivial. Evenso, I did hear a few spots in Parson's early work, like the Poe, that used vocoding decently, if also somewhat, as you suggest, pretentiously. And Laurie Anderson's always inventive in her work.

Question #4 -- What kind of vocoder do/did you prefer?

Felix Visser made the best ones, for his long-gone (alas!) Synton company, all during the 80's. Some other fine devices exist, as the EMI/Synthi big one, and Sennheiser's expensive one, those and dear Harald Bode's design that Moog's good 16-band one was similar to. The ultra-basic analog units were generally mushy-sounding. Synton's had the best intelligibility on spoken words for their original 32-band device, and musicality for the newer 14 band one I currently use: the Synton SPX 216.
 
Computerized versions can be better, but most so far aren't. Phase vocoders theoretically ought be even more precise and clear than channel units. I don't have as much experience with them, although there's a dandy one in the new SoundView program distributed by Peabody Digital (note: this APPL also contains the finest Sound Spectrograph program written for the Mac, developed by computer audio guru, Edmund Pirali.)

Question #5 -- Several of the contemporary pop musicians I've spoken to for this piece mentioned using the vocoder on materials other than the voice, ie. rhythms and such. Have you ever experimented/worked in this area?

I did this immediately after our first vocal uses, long before others "invented the same wheel". It can be effective. Best examples in my music are to be found all over "Beauty in the Beast", which will be rereleased in a new 20-bit version on ESD late this year. The notes to "BitB" mention a lot of the cases therein.

Question #6 -- What do you consider your greatest achievements? (Yes, it's that open ended -- there's much to be learned just from how folks interpret the question, isn't there?)

I guess this album, "Beauty in the Beast", is the most important in itself, pop culture considerations notwithstanding. And some of the new "Tales of Heaven and Hell" movements are surprisingly good, as I look back now. If you mean in synthesis, the LSI Philharmonic sound replicas in "Digital Moonscapes" were well in advance of decent sample based "orchestras in a box", and beyond into hybrid synthesis, still not too developed otherwise. But the way most folks interpret such questions is to point merely to what was most popular. SOB was an historic benchmark of sorts, I guess, but is hardly what might be counted a "greatest achievement" artistically. First steps are *learning* experiences. Wisdom can't arrive that young. That's just how human nature is made, don't blame me...! ;-)

Thank you, Ms. Carlos for a) your participation and b) making some great music that I've really enjoyed over the years.

Very kind of you, Kurt. Thanx for the good questions, and hope this is of help there at CMJ.

(Note: see the original 10-band vocoder at the top of the 1979 Moog synth on our Photos page, with a few comments about it and a list of all the other modules as well.)

Kurt B. Reighley
Editor At Large
CMJ New Music Monthly


Postscript Notes on Vocoders:

Since we've started receiving frequent messages from enthusiasts about vocoders, their use and history, let's add several additional notes about it to this page. There are now dozens of web sites which describe vocoders (and the voder) quite well. Since the list is constantly changing and expanding, we suggest that you type: <vocoder "homer dudley"> into the search string of your favorite Web Search Engine, and browse the many hits that will come up there.
 
Unfortunately, along with the current resurgence of interest in this nearly seven decade old device, a lot of urban legend pseudo-facts keep reappearing in a fog of factoids. So, just for the record:

1) The Vocoder was invented by Homer Dudley in the mid-30's. Dudley worked at Bell Laboratories, and this is where the first Vocoder took shape. The original vocoders, using tubes and bulky discrete components, occupied a tall rack of custom electronic modules, quite heavy, but elegant for its day.

2) VOCODER (note the spelling) is a shortening of Voice Coder. There's no second "r" in it (for vocal coRds?), puh-leeze. It literally coded a voice into control signals, then decoded those signals back into audible speech, in two mirror-image steps. Other "full" versions of the device's name, such as Voice Operated reCOrDER, are merely later plausible speculations, not at all what Dudley came up with.

3) Homer Dudley also invented the VODER (Voice Operating DEmonstratoR), an electronic speaking instrument, which was unveiled (and demonstrated hourly) at the New York World's Fair 1939-40. Inside the tall rack of sturdy electronic gear was a pitch controlled reedy oscillator, a white-noise source, and ten bandpass resonant filters. For a Voder to "speak" a talented, diligently trained operator "performed" at a special console connected to the rack, using touch-sensitive keys and a foot-pedal. These controlled the electronic generating components. The results, while far from perfect (it was damn difficult to operate!), were still entertaining and instructive of the principles involved.

4) The Vocoder was built in an attempt to save early telephone circuit bandwidth. So it had a prosaic "speech compression" goal (which the cost and complexity overrode). Dudley's breakthrough device analyzed wideband speech, converted it into slowly varying control signals, sent those over a low-band phone line, and finally transformed those signals back into the original speech, or at least a close approximation of it. It was also useful in the study of human speech, as a laboratory tool. Other applications came much later, including theatrical effects (robot voices) and singing synthesizers (now who would attempt a dopey idea like THAT? -- mea culpa...!).

5) The second half of a vocoder is pretty much the same as a voder. For the latter the performance console controlled those circuits directly and manually. But the Vocoder added a front half (with another, duplicate set of filters, along with as many envelope followers) which "analyzed" the energy in each band of an incoming speech signal. Then control signals (usually voltages), were output from this encoding stage into the decoding section. Given a well designed and adjusted unit, the resynthesized speech was often a very close match to the original. It was also easy to operate: you only had to speak into a mike fed to the encoding input.

6) Many "vocoding effects" from years ago were not actually done with a vocoder. Radio commercials in the 40's often featured speaking trains, door squeaks, talking mechanical or nature sounds, highlighting another popular device: the Sonovox. Gilbert Wright invented this mechanical means to impart the articulations of speech onto other sounds ("talk boxes" and "talk tubes" borrowed the idea more cheaply later on). The source sound was fed through a power amplifier into two small drivers, like loudspeakers -- but with each cone replaced with a flexible flat disk about 2" in diameter. When the disks were pressed on a performer's throat, on either side of her neck (most Sonovox performers were women, as with the Voder), audio sent into the drivers would substitute for vocal chord energy. The performer silently and carefully moved her mouth and tongue in the usual speaking gestures, also adding the "fricatives" ("s", "t", "sh", etc.). Close miking caught the result: be it a singing piano, crooning trombone, or talkative foghorn. Children's recordings from the 40's, like Rusty in Orchestraville, Sparky's Magic Piano, and several Disney animated cartoons (the train in Dumbo) feature the Sonovox. (The new DVD of Dumbo contains a video clip of it in action, take a look!) It's similar in resulting sound to a vocoder, but very different in execution and principle (physical, not electronic).

7) For a full "singing vocoder" effect, a singer's performance is input to the encoding section (you can just speak in rhythim, the pitch information is discarded). At the same time a bright synthesizer waveform is sent to the so-called "carrier input." That provides the raw energy for voiced sounds, equivalent to the vocal chords. Its pitch can be controlled from a music keyboard. Some vocoders have a noise generator onboard. If not, a white noise synth source is sent to the non-voiced input ("t", "s", "sh", "ch", "k" sounds need that). In many implementations a rapid switching circuit that alternates between voiced and non-voiced modes is built in. If not, external synth modules can be configured to provide the same result. A cruder if expedient technique is simply to mix the noise in with the oscillator, but the effect is less natural sounding.

8) At the risk of being preposterously premature, I'd like to alert all fans of the vocoder that a very bright (and witty) NYC author, Dave Tompkins, is currently writing a definitive book on Dudley's voice processing device. He's been interviewing many of us who've worked with vocoders over the years, and I expect it will be an excellent book. A whole secret world of vocoders being used in the 40s, 50s and 60s for defense purposes (yes!) comes as a complete surprise, along with many other long forgotten speech processing stories. I'd also like to thank Dave for recently bringing to mind the Eltro Mark II audio processor, which I've just documented on its own page (read all about it HERE). To tempt you to check it out, consider this surprising bit of trivia: Stanley Kubrick used the very same Eltro to create the lobotomized / dying voice of HAL in "2001," something I describe there, having experienced firsthand a little of this particular forgotten audio history.

9) BTW-- For more technically-minded fans of speech synthesis, there are several US Patent websites (can Google many of them, although you may already have your favorite) which have available online Dudley's original patents, including those describing early versions of the voder and vocoder. I like to save the PDF versions to print out for study later. The most interesting on this subject which I've found are the following patent numbers:

2,121,142  (Introducing the Voder)
2,151,091 
(Earliest Vocoder+ ideas)
2,243,526 
(Speech synthesis, part A)
2,243,527 
(Speech synthesis, part B)
2,466,880 
(Later Vocoder ideas)

--Wendy Carlos

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