EMUSIC-L Digest Volume 67, Issue 04 This issue's topics: Fractals, chaos, perception, and synthesis 3D Fractals Auditory perception and chaotic processes (15 messages) automata synthesis addendum Your EMUSIC-L Digest moderator is Joe McMahon . You may subscribe to EMUSIC-L by sending mail to listserv@american.edu with the line "SUB EMUSIC-L your name" as the text. The EMUSIC-L archive is a service of SunSite (sunsite.unc.edu) at the University of North Carolina. ------------------------------------------------------------------------ Date: Tue, 9 Aug 1994 08:43:03 -0500 From: Brian Good Subject: 3D Fractals Magnus Barber writes: > (Another question for the fractal-knower: (not related to > music) is a 3d fractal possible? How could this be displayed?) Sure. You should be able to find a picture of a Sierpinski sponge in one of the pop fractal books. brian good ------------------------------ Date: Wed, 10 Aug 1994 11:05:05 -0500 From: Joe McMahon Subject: Auditory perception and chaotic processes (was: physical modelling) [I sent this directly to Peter yesterday when I meant to include the whole list. Thanks for sending a copy back, Pete! -- JM] Peter Thorpe writes: >I'm not sure that there is an analog in sound to the beautiful pictures >created by fractal/chaotic algorithms. Hmmmm. How about the chaotic behaviors of the forced vibrations of air columns in traditional musical instruments? I agree that it is a different experience, certainly, but perhaps this is related to why physical modeling can sound more "real" than sample-based synthesis. I'm of the opinion that one of the reasons that analog is popular now is that the texture of analog synths is partially shaped by chaotic interactions among the operational parts. I remember Bob Moog making a remark about how component layout could make a major difference in whether an analog synth sounded "good" or not. >You >can't see a sound as a whole, and how would you know that the wonderful >picture you had on the screen sounded good? Very true. I think that the capabilities of the eye are much easier to explore than those of the ear. We know far more about visual illusions than we do about auditory ones - I believe that most of the well-known ones, such as Shepard tones, paradoxical stereo perception, phase illusions, and the like were never scientifically investigated or quantified until recently (say the last 20-30 years). Musicians (especially orchestra composers) have taken advantage of some of them (particularly paradoxical stereo perception), but formerly no one had been studying why these "tricks" worked. I'm not sure we know with enough precision *how* the ear works to be 100% sure (in the sense of an algorithmic process) of producing a given effect in a musical context. Perhaps further study of musical invariants is necessary to determine what is happening during the perception of sound and music. --- Joe M. -- "Now hold it down for an hour. Okay, now hold it down until you get a recording contract from Windham Hill." (MST3K) ------------------------------ Date: Wed, 10 Aug 1994 14:29:40 -0500 From: Arne Claassen ISE Subject: Re: Auditory perception and chaotic processes (was: physical > Very true. I think that the capabilities of the eye are much easier to > explore than those of the ear. We know far more about visual illusions than > we do about auditory ones - I believe that most of the well-known ones, > such as Shepard tones, paradoxical stereo perception, phase illusions, and > the like were never scientifically investigated or quantified until > recently (say the last 20-30 years). Musicians (especially orchestra > composers) have taken advantage of some of them (particularly paradoxical > stereo perception), but formerly no one had been studying why these > "tricks" worked. I've got a Shepard tone patch for my EPS and it fascinates me, even though the quality is not that great. I don't think i'm familiar with the other "tricks" Joe mentioned. Where can i find the theoretical basis of these "tricks" including Shepard tones? -- Arne F. Claassen ----------------------------------------------------------------------------- Nine Inch Nails on MTV Unplugged - "The whole band is onstage. Chris is behind the drums and a tape deck not plugged in, no sound. Everybody's waiting to play. He hits it again. Nothing. I yell at him. He hits it again. Nothing. Then we smash our gear and walk offstage!" ------------------------------ Date: Wed, 10 Aug 1994 16:03:38 EDT From: "william.b.fox" Subject: Re: Auditory perception Joe said: > [ big snip ] > such as Shepard tones, paradoxical stereo perception, phase illusions, and > the like were never scientifically investigated or quantified until > [ another snip ] I'd like to see the definitions of these tricks. Anybody have tips on how to program these on a synth or compose them into an orchestral piece? Bill Fox wbf@aloft.att.com ------------------------------ Date: Wed, 10 Aug 1994 16:03:43 CST From: "Harry F.P. Haecker" Subject: Re[2]: Auditory perception and chaotic processes (was: physi >I've got a Shepard tone patch for my EPS... Hi, all... Could you briefly explain what a Shepard tone is, and could a K2000 mimic this effect? What is the "trick" that it plays on one's auditory perception? Also, what's an EPS synth? I'm glad this thread is going on, since I had thrown a similar topic out to everyone about three months ago concerning natural chaotic systems and physical modelling. Harry Haecker (haeckerh@nwrc.gov) ------------------------------ Date: Wed, 10 Aug 1994 17:10:46 -0500 From: Joe McMahon Subject: Re: Auditory perception and chaotic processes (was: physical Shepard tones; these give the illusion of perpetually descending or ascending scales, without any change of octave. Sort of like Escher's stairs which go round and round but never go up or down. This is done by having a tone with companion tones an octave above and an octave below the "center" tone, fading the high tone out and the low tone in as the scale ascends, and vice versa as the scale descends. A very odd sensation. Paradoxical stereo perception: there are a lot of strange things that go on with stereo perception. For instance, if you supply two tones which are a few Hz out of tune with each other, one to the left and one to the right ear, beats will be perceived even though the two waves never interact physically. The normal explanation of beats depends on the reinforcement and cancellation of the wavefronts as they travel through space to reach the ear. Even with complete isolation of the two ears, the beats are still perceived. It's possible that the internal resonances of the head are allowing the beats to be perceived, but it's still not definitely explained. Also, if a descending scale is presented to one ear and an ascending one to the other, the actual perceived sound is one voice descending halfway and then ascending, with the voice in the other ear ascending halfway and then descending. It's possible to play other tricks with a melody which actually jumps around quite a bit with a different one in the other ear; this same organizational oddity takes over and produces a different perception. This has been used by ochestral composers, though I've forgotten the best example - it used an interaction between the first and second violins on the opposite sides of the orchestra to produce a texture different from that played by either. Phase illusions: most often exploited by things such as the "stereo-wide" switch on boom-boxes. Turning this on adds a certain amount of out-of-phase information from each channel to its opposite, fooling our internal head-transfer functions into thinking that the sound sources are physically further apart than they actually are. (I'm not precisely sure of the mechanism here, but recall that this is it; corrections, please?) Of course, in mono this will cause some phase cancellation, making the sound "weak". Most of these can be simulated on a reasonably-programmable synth; someone on the K2000 list had mentioned using the phase illusion stuff as a means of "widening" a sample. Information is dredged out of my memory; there was a Scientific American article on the beat perception stuff in the late 70's/early 80's; Shepard tones have been around longer than that, as I recall - most books on human perception will at least mention them; the phase illusions have been, as I mentioned, exploited in boom boxes and in Carver's "Sonic Holography" equipment. --- Joe M. -- "Somebody's got his finger on a DX7." (MST3K - "Being from Another Planet") ------------------------------ Date: Wed, 10 Aug 1994 20:12:00 -0500 From: Arne Claassen ISE Subject: Re: Re[2]: Auditory perception and chaotic processes (was: physi > Could you briefly explain what a Shepard tone is, and could a K2000 > mimic this effect? What is the "trick" that it plays on one's > auditory perception? Also, what's an EPS synth? As far as i understand a shepard tone is one that gives the illusion of continually ascending or descending. The EPS is a sampler, so my shepard tone is just a sample of a single period of that tone. I got the sample off the net somewhere. I.e. it'll work just as well on a K2000 if you can get a sample. -- Arne F. Claassen ----------------------------------------------------------------------------- Nine Inch Nails on MTV Unplugged - "The whole band is onstage. Chris is behind the drums and a tape deck not plugged in, no sound. Everybody's waiting to play. He hits it again. Nothing. I yell at him. He hits it again. Nothing. Then we smash our gear and walk offstage!" ------------------------------ Date: Wed, 10 Aug 1994 23:10:15 -0500 From: Siberian Khatru Subject: Re: Auditory perception and chaotic processes (was: physical With respect to shephard tones, I didn't know it when I first saw the term (shepherd tones) but I had run across the same phenomenon a few years ago. I remember a short article in Keyboard magazine which explained how to simulate a "sonic barberpole" (their term). It didn't click until I read Joe's definition of "shepherd tones". I can't recall off the top of my head (or any part for that matter) which issue it was in, so I'll look and post post it when I find it. Cheers, Jon Southwood jsouthwo@keller.clarke.edu ****************************************************************************** "I once played poker with a deck of tarot cards. I got a full house and four people died."-Steven Wright "If I had only known, I would have been a locksmith."-Albert Einstein "Truly great madness cannot be achieved without significant intelligence." -Henrik Tikkanen ****************************************************************************** ------------------------------ Date: Thu, 11 Aug 1994 08:51:13 -0700 From: "Shawn T. Rutledge" Subject: Re: Auditory perception and chaotic processes (was: physical > I've got a Shepard tone patch for my EPS and it fascinates me, even though the Do you know where you got it? IE, is it on the net somewhere? -- _______ KB7PWD shawn.rutledge@asu.edu (_ | |_) html: http://enuxsa.eas.asu.edu/~rutledge/home.html __) | | \__________________________________________________________________ * virtual reality * sci fi * freedom of information * alternative energy * ------------------------------ Date: Thu, 11 Aug 1994 10:51:51 -0500 From: Macalester College Music Department Subject: Re: Auditory perception and chaotic processes (was: physical One of the best examples I know of two opposing melodic structures in first and second violins combining to produce a melody in the ear which no single instrument plays is the violin(s) melody which appears at the opening of the fourth movement of Tschaikowsky's Symphony #6, (Pathetique). Is this what you were thinking of? I would be interested in learning of other examples. +-----------------------------------------------------------------------+ + Ed Forner Macalester College Music Department + + in%"forner@macalstr.edu" voice (612) 696-6189 + +-----------------------------------------------------------------------+ ------------------------------ Date: Thu, 11 Aug 1994 12:47:30 -0500 From: Joe McMahon Subject: Re: Auditory perception and chaotic processes (was: physical Ed Forner writes: >One of the best examples I know of two opposing melodic structures in first and >second violins combining to produce a melody in the ear which no single >instrument plays is the violin(s) melody which appears at the opening of the >fourth movement of Tschaikowsky's Symphony #6, (Pathetique). Is this what you >were thinking of? I would be interested in learning of other examples. Very probably. I was also just now remembering that there was a NOVA episode entitled "What is Music?", which went into this quite a bit; this is where I remember the symphomic example from. Wendy Carlos has used this trick very interestingly in her piece "Geodesic Dance"; she also used it to very good effect in the Scarlatti keyboard sonatas realized on "The Well-Tempered Synthesizer". I believe that this is out of print and not available on CD - I'd love to be wrong! She dissects a section of one of the sonatas, playing the parts separately and then all together, on her "Secrets of Synthesis" album. --- Joe M. -- "Somebody's got his finger on a DX7." (MST3K - "Being from Another Planet") ------------------------------ Date: Thu, 11 Aug 1994 18:45:14 EDT From: "Brian R. Warren" Subject: Re: Auditory perception and chaotic processes (was: physical > Information is dredged out of my memory; there was a Scientific American > article on the beat perception stuff in the late 70's/early 80's The article you are probably thinking of is "Musical Illusions" by Diana Deutsch, Scientific American, October 1975, p. 92. I haven't seen the article yet, so I can't supply specifics about the contents. More recently, Diana Deutsch published an article in Scientific American, "Paradoxes of Musical Pitch," August 1992, p.88. It goes into some detail about experiments she performed, creating Shepard tones and observing perceptual responses. She tested groups of subjects in both England and California, and found that each group perceived the Shepard tones in a different way, due to the differences in their speech patterns. ------------------------------ Date: Thu, 11 Aug 1994 17:48:00 PST From: Barry Klein 714-932-7493 Subject: Re: Auditory perception and chaotic processes (was: physical Where can this "Secrets of Synthesis" CD be purchased? I can't find it in stock anywhere. b_klein@a1.wdc.com ------------------------------ Date: Thu, 11 Aug 1994 21:03:41 -0500 From: Arne Claassen ISE Subject: Re: Auditory perception and chaotic processes (was: physical >>I've got a Shepard tone patch for my EPS and it fascinates me, even though the > > Do you know where you got it? IE, is it on the net somewhere? It was on the EPS mailing list FTP site. Since then the list and the site has moved and i've lost touch with it. Sorry. -- Arne F. Claassen ----------------------------------------------------------------------------- Nine Inch Nails on MTV Unplugged - "The whole band is onstage. Chris is behind the drums and a tape deck not plugged in, no sound. Everybody's waiting to play. He hits it again. Nothing. I yell at him. He hits it again. Nothing. Then we smash our gear and walk offstage!" ------------------------------ Date: Mon, 15 Aug 1994 13:16:00 -0700 From: Peter Mueller Subject: Re[2]: Auditory perception and chaotic processes (was: physical >>I've got a Shepard tone patch for my EPS and it fascinates me, even though the > > Do you know where you got it? IE, is it on the net somewhere? It was on the EPS mailing list FTP site. Since then the list and the site has moved and i've lost touch with it. Sorry. -- Arne F. Claassen try ftp-ing oak.oakland.edu /pub2/eps/ I haven't looked for shepard tones there, but that's where the eps site is (it's no longer at reed) -Peter. ----------------------------------------------------------------------------- Nine Inch Nails on MTV Unplugged - "The whole band is onstage. Chris is behind the drums and a tape deck not plugged in, no sound. Everybody's waiting to play. He hits it again. Nothing. I yell at him. He hits it again. Nothing. Then we smash our gear and walk offstage!" >-- Saved internet headers (useful for debugging) >Received: from AUVM.AMERICAN.EDU by ucsd.edu; id TAA17506 sendmail 8.6.9/UCSD-2 >Message-Id: <199408120212.TAA17506@ucsd.edu> >Received: from AUVM.AMERICAN.EDU by AUVM.AMERICAN.EDU (IBM VM SMTP V2R2) with >Received: from AMERICAN.EDU (NJE origin LISTSERV@AUVM) by AUVM.AMERICAN.EDU (LM >Date: Thu, 11 Aug 1994 21:03:41 -0500 >Reply-To: Electronic Music Discussion List >Sender: Electronic Music Discussion List >From: Arne Claassen ISE >Subject: Re: Auditory perception and chaotic processes (was: physical >Comments: To: EMUSIC-L@AMERICAN.EDU >To: Multiple recipients of list EMUSIC-L >In-Reply-To: <9408111544.AA24303@ebs330> from "Shawn T. Rutledge" at Aug 11, >X-CCaddr: Bcc: peter mueller AT ucsdlibrary >X-CCaddr: *To: EMUSIC-L@AMERICAN.EDU at @UCSD ------------------------------ Date: Mon, 15 Aug 1994 16:20:38 -0700 From: "Shawn T. Rutledge" Subject: Re: Re[2]: Auditory perception and chaotic processes (was: physical > try ftp-ing oak.oakland.edu /pub2/eps/ > I haven't looked for shepard tones there, but that's where > the eps site is (it's no longer at reed) Looked - nothing there, at least not under any obvious name (ie, a name containing "shep"). Also did an archie search - found a "shepard.tar.Z " - guess I'll find out what that is. -- _______ KB7PWD shawn.rutledge@asu.edu (_ | |_) html: http://enuxsa.eas.asu.edu/~rutledge/home.html __) | | \__________________________________________________________________ * Interpedia * PIC * IEEE * freedom of information * cyberspace * ARS * ------------------------------ Date: Wed, 10 Aug 1994 13:36:16 -0500 From: Joe McMahon Subject: automata synthesis addendum I'm going to check the CMJ WWW site later today, but here's another thought on converting automaton states to waveforms: Run a wide automaton (e.g., several hundred bits) and sum all of the "on" bits in each state. 16-bit resolution would give you up to a possible 2 to the 16th or 65536 cells. Plenty of room to let configurations evolve. Remembering the waveform plots from the article, I'm betting this was actually the method, not the one I mentioned before. However, given that there are now analysis tools which will (with a lot of work) allow you to design an automaton withing certain bounds of behavior, this might be worth pursuing. --- Joe M. -- "Somebody's got his finger on a DX7." (MST3K - "Being from Another Planet") ------------------------------ End of the EMUSIC-L Digest ******************************