EMUSIC-L Digest Volume 67, Issue 06 This issue's topics: Shepard.mid.uu Shepard tones (5 messages) Shepard tones via synth (3 messages) Shepard.mid.uu (10 messages) What are shepard tones????? (2 messages) 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: Thu, 11 Aug 1994 15:27:58 -0700 From: Andrew Sharpe Subject: Re: Shepard tones Well, I tried to make a Shepard tone last night, and I pretty much failed. But, having never heard one before, it's difficult to say what I expected. Here's what I did (you may flame at will): Channel 1 - Basic ascending C Major scale, velocity 100 Channel 2 - Same scale, octave below, velocity varied from 20 to 127 Channel 3 - Same scale, octave above, velocity varied from 127 to 20 What am I missing? A# ------------------------------ Date: Thu, 11 Aug 1994 17:27:30 -0700 From: Andrew Sharpe Subject: Re: Shepard tones Sorry, I _was_ using volume, I tend to treat them as synonyms, because it appears that most sequencers do. Certainly, the two channels that had varying velocity settings _did_ indeed increase and decrease in volume. A# On Aug 11, 8:15pm, xrjdm@farside.gsfc.nasa.gov (Joe McMahon) wrote: : >Channel 1 - Basic ascending C Major scale, velocity 100 : >Channel 2 - Same scale, octave below, velocity varied from 20 to 127 : >Channel 3 - Same scale, octave above, velocity varied from 127 to 20 : > : >What am I missing? : : Try volume instead of velocity - that may help. : : --- Joe M. : : -- : "Somebody's got his finger on a DX7." (MST3K - "Being from Another Planet") ------------------------------ Date: Thu, 11 Aug 1994 20:15:46 -0500 From: Joe McMahon Subject: Re: Shepard tones >Channel 1 - Basic ascending C Major scale, velocity 100 >Channel 2 - Same scale, octave below, velocity varied from 20 to 127 >Channel 3 - Same scale, octave above, velocity varied from 127 to 20 > >What am I missing? Try volume instead of velocity - that may help. --- Joe M. -- "Somebody's got his finger on a DX7." (MST3K - "Being from Another Planet") ------------------------------ Date: Thu, 11 Aug 1994 21:04:02 -0700 From: Nate Waddoups Subject: Re: Shepard tones On Thu, 11 Aug 1994, Andrew Sharpe wrote: > Channel 1 - Basic ascending C Major scale, velocity 100 > Channel 2 - Same scale, octave below, velocity varied from 20 to 127 > Channel 3 - Same scale, octave above, velocity varied from 127 to 20 > > What am I missing? I did pretty much the same thing a couple/few months ago. As I recall, the biggest problem I had was finding a patch with the right dynamics. Those velocity=20 notes ought to be just barely audible, and the 127's ought to be reasonably loud. I never did get a truly convincing result, but it was pretty interesting. +-------------------+------------------------------------------------------- | natew@halcyon.com | You write Windows code? Mac code? OS/2 PM code? +-------------------+ Want a great job in the pacific northwest? Send me email, we'll talk... ------------------------------ Date: Fri, 12 Aug 1994 08:13:58 -0500 From: Joe McMahon Subject: Re: Shepard tones >Sorry, I _was_ using volume, I tend to treat them as synonyms, because >it appears that most sequencers do. Certainly, the two channels that >had varying velocity settings _did_ indeed increase and decrease in >volume. I'm wondering if it could be that the fade-in/fade-out might need to follow a logarithmic curve rather than a linear one (which is what I suspect you may be getting). Certainly the ear responds logarithmically, anyway... I apologize for not having a more technically-detailed description. Should I find one I'll post it. (Of course, anyone else who finds it before I do may feel free to do so.) --- Joe M. -- "Somebody's got his finger on a DX7." (MST3K - "Being from Another Planet") ------------------------------ Date: Thu, 11 Aug 1994 11:56:31 CST From: "Harry F.P. Haecker" Subject: Shepard tones via synth >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! I'm *surprised* at you. That's cheatin'! ;-) Cheating, at least in terms of knowing the grassroots basis of how to construct an example of one. However, if all else fails, I may have to resort to using my sampler in the fashion in which it was "meant" to be used... Actually, after Joe was nice enough to post the near-textbook quality definitions of the auditory illusions, I started wondering if my TG-77 would be better equipped to produce the effect via additive synthesis than the K2000RS. Synthetically Y'all's, Harry Haecker (haeckerh@nwrc.gov) ------------------------------ Date: Thu, 11 Aug 1994 17:11:29 -0400 From: "Keith C. Perry" Subject: Re: Shepard tones via synth >>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. Hmmm, I wonder... If someone was able to get that sample into the standard midi sample dump format and then uuencode and post it to the net or preferably give us a site to get it from well all could take adavange to it. Whoops, shame on me... Keith C. Perry - (800)-836-4599 ************************************************************************** * * *Floor Supervisor / Senior Consultant - Drexel University CRG, OCS Group * *Owner / Studio K Productions * * * * "Ok, ok, ok, nah wait- ar'ite, wait- ok, yea thats cool- but..." * * * * -Things you hear when someone is talking on the phone- * * * ************************************************************************** ------------------------------ Date: Thu, 11 Aug 1994 21:08:10 -0500 From: Arne Claassen ISE Subject: Re: Shepard tones via synth > Arne! I'm *surprised* at you. That's cheatin'! ;-) Cheating, at > least in terms of knowing the grassroots basis of how to construct an > example of one. However, if all else fails, I may have to resort to > using my sampler in the fashion in which it was "meant" to be used... Um... well, before i got the sample i'd heard of a shepherd tone but had never "heard" one, so i didn't know how to create it. After getting it i've been toying setting up a sequence for my Juno106 that emulates it using a loop and pitch bend. Since my computer's been out of commission, i've not been able to do this yet. I don't think my Juno could do it by itself, tho. -- 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, 29 Aug 1994 07:58:14 -0400 From: "B. Kirsch" Subject: Shepard.mid.uu Shepard Tones is analogous to a barbershop pole going up and up and up... If you look at the uu encoded file of Shepard that Andrew Sharpe posted, it seems to look banded like a barbershop pole. Is this coincidence? Barry Kirsch bkirsch@nadc.navy.mil ------------------------------ Date: Mon, 29 Aug 1994 16:35:14 -0400 From: Polaris Subject: Re: Shepard.mid.uu > Shepard Tones is analogous to a barbershop pole going up and up and up... > If you look at the uu encoded file of Shepard that Andrew Sharpe posted, > it seems to look banded like a barbershop pole. Is this coincidence? Sorri I didn't catch the beginning of this thread, but I was just discussing Shepard Tones last week. Check out the sheet music to Bach's Musical Offering to see Shepard tones in action. There are also a few pages devoted to Shepard tone's in Douglas R. Hofstadter's Godel, Escher, BAch: An Eternal Golden Braid [pp. 717-719]. In case you have it lying around. You can also check out Roger N. Shepard's article "Circularity in Judgments of Relative Pitch" which appeared in Journal of the Acoustical Society of America. The issue is vol. 36, no. 12 (december 1964) [pp. 2346-2353]. The is the definitive article on Shepard Tones and if you have a good college library around, they should have it. The piece by Bach has all kinds of wonderful things going on in it, so it's nice to have some critical literature about. Fortunately, my rommate has volumes of this kind of thing lying around. Anyway, this is the piece where Bach has imbedded his own name. Have fun and if anyone else has references, please send them to me as well as posting them here. Later, Polaris |9 (<--this is chop lickin' w/ a big grin if ya can't figure it out) __________________________________________________________________________ (*__________________________________________________________________________*) ___________ |\ ___ \ \ \ \ \ \ >>Wall of Sound Productions<< \ \ \__\ \ .MAKING.DREAMS.REALITY. \ \ _____\ \ \ \____| Internet: Taka-03@InfiNet.com \ \ \ Sound Bytes BBS: 614.761.1602 \ \ \ OLARIS MIDILink: via Sound Management BBS \ \____\ Ambient*Progressive House*Traxx*Trance*Ethnic \|____| Bubblegum Crisis*Bubblegum Crash*Dominion*Appleseed __________________________________________________________________________ (*____G_E_N_K_I__D_E_!___I_K_U__Z_O_!___M_A_T_A__N_E_!___R_A_V_E__O_N_!_____*) ------------------------------ Date: Mon, 29 Aug 1994 14:08:00 -0700 From: Peter Mueller Subject: Re[2]: Shepard.mid.uu " Check out the sheet music to Bach's Musical Offering to see Shepard tones in action. .... Anyway, this is the piece where Bach has imbedded his own name. You mean the Art of the Fugue, don't you? ------------------------------ Date: Mon, 29 Aug 1994 20:16:24 -0400 From: Polaris Subject: Re: Re[2]: Shepard.mid.uu > " Check out the sheet music to Bach's Musical Offering to see Shepard > tones in action. .... > Anyway, this is the piece where Bach has imbedded his own name. > You mean the Art of the Fugue, don't you? Actually, you are right. That is where I first heard of him doing this also. I guess with Musical Offering he spreads it accross the upper and lower registers. Come to think of it, Musical Offerings is the close cousin of Art of the Fugue. Bach was to perform at Potsdam and for the occassion he based MO on a theme given to him by Fredrick the Great. The tie here is the autonomous polyphonic style in both works. Actually MO lead to an improvised work (I don't recall the name--if it even has one) on his return to Germany from Potsdam which helped (along with AotF) bring to a close this style. Definitely AotF is the more famous and notable of the two. Thanks for the addition. Anyone else out there with examples of Shepard tones? I know there are more... (although AotF is NOT one of them) Later, Polaris |9 (<--this is chop lickin' w/ a big grin if ya can't figure it out) __________________________________________________________________________ (*__________________________________________________________________________*) ___________ |\ ___ \ \ \ \ \ \ >>Wall of Sound Productions<< \ \ \__\ \ .MAKING.DREAMS.REALITY. \ \ _____\ \ \ \____| Internet: Taka-03@InfiNet.com \ \ \ Sound Bytes BBS: 614.761.1602 \ \ \ OLARIS MIDILink: via Sound Management BBS \ \____\ Ambient*Progressive House*Traxx*Trance*Ethnic \|____| Bubblegum Crisis*Bubblegum Crash*Dominion*Appleseed __________________________________________________________________________ (*____G_E_N_K_I__D_E_!___I_K_U__Z_O_!___M_A_T_A__N_E_!___R_A_V_E__O_N_!_____*) ------------------------------ Date: Tue, 30 Aug 1994 08:24:12 -0400 From: Mark G Simon Subject: Re: Re[2]: Shepard.mid.uu > " Check out the sheet music to Bach's Musical Offering to see Shepard > tones in action. .... > Anyway, this is the piece where Bach has imbedded his own name. > > You mean the Art of the Fugue, don't you? Some scholars claim Bach employed a number-alphabet to encode messages into his scores (A=1, B=2, C=3, etc.). So that if a phrase of 10 notes (J) were followed by a phrase of 19 notes (S) and then 2 notes (B), 1 note (A) 3 notes (C) then 8 notes (H), one might find the name J S BACH in the music. These musical numerologists have investigated great chunks of Bach's music looking for things like this, and claim to have found his name, along with other words, mostly of religious significance (Christus, Jesu, etc), embedded in many of his scores. Whether Bach intended any of this is still under debate. In any case, this has very little to do with Shepard tones as described in previous postings, and I really would not expect to find this phenomenon in any score of JS Bach, except maybe for "Sheep May Safely Graze", and those, of course would actually be Shepherd tones. Mark Simon mgs2@cornell.edu ------------------------------ Date: Tue, 30 Aug 1994 09:47:16 -0400 From: binary sound 10011011 Subject: Re: Re[2]: Shepard.mid.uu > > Some scholars claim Bach employed a number-alphabet to encode messages > into his scores (A=1, B=2, C=3, etc.). So that if a phrase of 10 notes > (J) were followed by a phrase of 19 notes (S) and then 2 notes (B), 1 > note (A) 3 notes (C) then 8 notes (H), one might find the name J S BACH > in the music. These musical numerologists have investigated great chunks > of Bach's music looking for things like this, and claim to have found his > name, along with other words, mostly of religious significance (Christus, > Jesu, etc), embedded in many of his scores. Whether Bach intended any of > this is still under debate. In any case, this has very little to do with > Shepard tones as described in previous postings, and I really would not > expect to find this phenomenon in any score of JS Bach, except maybe for > "Sheep May Safely Graze", and those, of course would actually be Shepherd > tones. > the way i learned of this (in hofstedler's (?) book, _Godel, Escher, Bach_..it's real neat). But in German and some other languages, H is what we call a B flat. And, B is just B. To me, this is the more likely explanation, because the phrase is so strange it has to be intentional. =) the book explains it all a little more, including that stuff about the melody for Frederick and such. john ------------------------------ Date: Tue, 30 Aug 1994 09:27:59 -0500 From: Joe McMahon Subject: Re: Re[2]: Shepard.mid.uu > ... except maybe for >"Sheep May Safely Graze", and those, of course would actually be Shepherd >tones. Mark, have I forgotten to mention that you're evil? :) --- Joe M. -- "Now then, Rothwell," she hisses. "Program this!" (S. Verity) ------------------------------ Date: Tue, 30 Aug 1994 11:21:22 -0400 From: Mark G Simon Subject: Re: Re[2]: Shepard.mid.uu > > > the way i learned of this (in hofstedler's (?) book, _Godel, Escher, > Bach_..it's real neat). But in German and some other languages, H is > what we call a B flat. And, B is just B. To me, this is the more likely > explanation, because the phrase is so strange it has to be intentional. =) > the book explains it all a little more, including that stuff about the > melody for Frederick and such. Actually, it's the other way around. To the Germans B natural = H and B flat = B. Mark Simon mgs2@cornell.edu ------------------------------ Date: Wed, 31 Aug 1994 21:02:23 MEZ From: Thomas Subject: Re: Re[2]: Shepard.mid.uu > But in German and some other languages, H is > what we call a B flat. And, B is just B. To me, this is the more likely > explanation ... It's just the other way round. What you call B is a H for us and what you call B-flat is just a B. So by writing B-A-C-H (B-flat-A-C-B) Bach could well spell his name in notes. Interesting enough, the last fugue he wrote, (no 15 from The Art Of Fugue) ends unfinished shortly after introducing the 3rd theme which starts with just these notes. On the other hand, these notes form the symbol of the cross while being a symbol of suffering according to the baroque affection theory (I don't know the English expression for this). It is well known that Bach composed many of these numerological things as well as those acronyms intentionally. ... just what I know... Thomas ------------------------------ Date: Wed, 31 Aug 1994 16:12:29 -0400 From: Mark G Simon Subject: Re: Re[2]: Shepard.mid.uu > a symbol of suffering according to the baroque affection theory > (I don't know the English expression for this). The most popular English term is "Doctrine of the affections", to distinguish it from the aesthetic principal of contemporary academic music, which is the "Doctrine of the affectations". Mark Simon mgs2@cornell.edu ------------------------------ Date: Wed, 31 Aug 1994 14:19:23 -0700 From: atomic city Subject: Re: Re[2]: Shepard.mid.uu Mark G Simon jotteth.... > >The most popular English term is "Doctrine of the affections", to >distinguish it from the aesthetic principal of contemporary academic >music, which is the "Doctrine of the affectations". ZZZZZINGG! Score another one for the Ithaca Mangler! :) -- mike metlay * atomic city * box 81175 pgh pa 15217-0675 * atomic@netcom.com --------------------------------------------------------------------------- "The juvenile sea squirt wanders through the sea searching for a suitable rock or hunk of coral to cling to and make its home for life. For this task it has a rudimentary nervous system. When it finds its spot and takes root, it doesn't need its brain any more so it eats it. It's rather like getting tenure." (d. c. dennett, in "consciousness explained") ------------------------------ Date: Fri, 19 Aug 1994 14:12:07 EDT From: "Patrick C." Subject: What are shepard tones????? can someone explain? ------------------------------ Date: Fri, 19 Aug 1994 14:45:29 -0500 From: Joe McMahon Subject: Re: What are shepard tones????? >can someone explain? >From F. Richard Moore's "Elements of Computer Music" (n.b. - here's the exact description of the method of synthesizing them, folks! Sorry I didn't remember this was sitting on the shelf behind me...): [begin excerpt] One interesting and well-known acoustical illusion was discovered in the 1960s by Roger Shepard, a research psychologist who worked at AT&T Bell Laboratories while much of the early work on computer music was taking place... Shepard tones exhibit the peculiar property of _circular pitch_ in the sense that if one constructs a musical scale out of them, the pitches eventually repeat themselves when the notes of the scale are played consecutively upward or downward. The illusion is that the notes have either continually increasing or decreasing pitch while simultaneously staying at or near the same place, similar to the optical barber-pole illusion in which helical stripes painted on a rotating cylinder appear to move up or down as the cylinder rotates without ever moving off the ends of the pole. Shepard created this effect by synthesizing a complex tone consisting only of components that are equally spaced on a log frequency scale. For instance, if all components are spaced an octave apart, their frequencies are constrained to lie at _f_, _2f_, _4f_, _8f_, _16f_, and so on, where _f_ is the frequency of the lowest component.... [end excerpt] The frequency distributions have to fit a somewhat bell-shaped curve (actually an inverted cosine) for the illusion to work properly. This "amplitude window" stays fixed, as the notes move upward or downward, fading the low components in and the high ones out as the tones ascend, and vice versa as they descend. | a | m | p | * l | * * i | * * t | * * u | * * d | * * e | * * | * * * * +------------------------------------------ log(frequency) Jean-Claude Risset extended Shepard tones to tones which continuously glide upward or downward while maintaining their frequency relationships, almost exacly duplicating the barber-pole effect. It sounds like Shepard tones could be done with a little thought on the K2000, with its function-based processing, and it would be my guess that it would be difficult on most other digital machines, and perhaps just barely possible on an old-style patch-programmed analog machine. Realistically, this is probably best synthesized by calculations and then played back by direct D-to-A conversion or by a sampler. I would guess that Risset tones would _have_ to be calculated and synthesized, perhaps as a sample which could be looped. --- Joe M. -- "First up, it's John Tesh, with 'Whispering Firestorm', followed by Yanni and his 'Snoremaster of Tralfamadore.'" (MST3K - "Pod People") ------------------------------ End of the EMUSIC-L Digest ******************************