**** All replies to this message should be sent to r...@eddie.mit.edu; I do n_t read these newsgroups. I will summarize and post any info I receive back to the net!
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I am a musician/hacker with an interest in sonic imaging (sonic holography). I am familiar with the Carver sonic hologram generator and the basic principle used by the device. However, I recently became aware of some experimental techniques in this area that are based, so I've been told, on some of same principles used in modern radarequiptment (E.G. for beam steering). Unfortunately, I forget the jargon term used to describe the process, but its something like "phase encoding ... :-)." Does anyone out there have any info on this?
In order to experiment with sonic holography, I would like to obtain a computer which is suitable for real-time audio processing. I'm sorta familiar with the Amiga, and less so with the Mac. The Amiga, as I understand, has a special]purpose chip used exclusively for audio signal processing, as well as A/D and D/A hardware in the basic system box. Whatyis the speed and resolution of the hardware? I was under the impression hhat the sample size is only 8 bits (poor resolution if ya ask me). What is thM?hhardware on the Mac like?
As I see it, my choice of what system to buy is based on the following. First, I need a fast processor (at least 1 mip +), I would estimate at least 1 meg of ram (more is always better), and an environment flexable enough to facilitate large-scale program developement (E.G. UNIX or equivalent). Secondly, I am blind, so I don't want hardware/software hooked to a grmphical user interface (gimme a good old command-lin5-interpreter like CSH and I'll be happy). From what I understand, graphical user interfaces are an integral part of todays music type software (samplers, sequencers etc.), as well as machines/os's like the Mac and Amiga. Does anyone know to what extent this is true, and how I might avoid this trap?
Thanx for your help. Any information/comments will be most apriciated. Please send all replies to me, however, for I don't read these Newsgroups!!!
-- -- Rich (r...@eddie.mit.edu). The circle is open, but unbroken. Merry meet, merry part, and merry meet again.
Sonic holograms ? Yes, a friend of mine has a Carver as well. Mighty impressive.
I'd be interested in whatever anybody has along these lines for the Amiga.
Plus, there is an audio illusion I've been looking for, for quite a while now. Basically it is an ever increasing tone.
There was a display at the Ontario Science center, ohh, 12 years or so ago, about MC Escher, that had a ball bouncing "up" an ever increasing staircase, with this tone, going up in pitch.
It went up in pitch for the 1/2 hour I stood there. :-)
Any clues ?
-- Richard J. Sexton INTERNET: rich...@gryphon.CTS.COM UUCP: {hplabs!hp-sdd, sdcsvax, ihnp4, nosc}!crash!gryphon!richard
I was at the New York City Audio Engineer Society convention last month, there was a company there which was selling compact disks of "holograms". The demonstration was really impressive. There was definitely a 3D effect especially the haircut thing where they have scissors going around you head and they trim the back with an electric razor. All with a standard CD player and ordinary headphones. Rodney Peck Rodney_Peck@rpitsmts%itsgw.rpi.edu
>There was a display at the Ontario Science center, ohh, 12 years or so >ago, about MC Escher, that had a ball bouncing "up" an ever increasing >staircase, with this tone, going up in pitch.
>It went up in pitch for the 1/2 hour I stood there. :-)
The effect you are looking for is produced by having two tones, one an octave above the other. As they rise in unison, the lower tone slowly becomes louder and the higher one becomes softer, until when they have gone up an octave, the upper tone has completely died out and the lower is where the upper started. Then you bring in a weak tone where the lower one started, and repeat. The ear fools you into thinking it is rising forever.
It might work better with more than two tones at octave intervals, but the idea is the same.
A sound that goes up in pitch for 1/2 hour is possible. The human ear has an amazing capacity to detect subtle changes in pitch. I have played around a bit, and gotten tones starting a reletively high(10Khz?) frequencies to go up in pitch for 3+ minutes. My guess is that they really just started at a very low frequency and went up to a very high frequency at some slow rate. If anyone has a bent for such things you can compute the 20hz-20Khz hearing range, into delta-hz/sec, and figure out from some source if the human ear could detect this slow of a change. On the other hand, I might not know what the heck I am talking about.
[-----------------------------------------------------------------------] [ Michael J. Bauers ( senior Computer Science at NDSU ) ] [ Reply to: NU100356@NDSUVM1 or ncbau...@ndsuvax.UUCP ] [ ] [ For God so loved the world that he gave his only son so that whoever ] [ believes in him will not perish, but shall have eternal life. ] [ ] [ Disclaimer: Frankly I do not think NDSU cares what I think, ] [ or even that I think at all. ] [-----------------------------------------------------------------------]
I think the proper name for something that produces a sound that appears to have an ever-increasing pitch is a continuously-rising tone generator. To make one, you create many tones, more or less evenly distributed over the entire audible frequency range. As a component tone rises to a frequency exceeding normal hearing, it is eliminated and replaced by a tone with a frequency that is below the normal hearing range. Since one can't hear the tones being eliminated or added, all one is left with is the impression of continuously-rising tones. -WBE
> Plus, there is an audio illusion I've been looking for, for quite > a while now. Basically it is an ever increasing tone.
> There was a display at the Ontario Science center, ohh, 12 years or so > ago, about MC Escher, that had a ball bouncing "up" an ever increasing > staircase, with this tone, going up in pitch.
> It went up in pitch for the 1/2 hour I stood there. :-)
> Any clues ?
Yup. I saw a film of this back in the 70's. The film was created at Bell Labs. The effect is easy to reproduce. The bouncing sound is the sum of several frequencies from 0 - 20 Khz weighted by a gaussian distribution with the hump of the curve starting at the lowest frequencies. Now increase the volumn on adjacent frequencies by sliding the distribution up the scale. Your ear assumes that the loudest frequency is the one that you heard the last time but increased in pitched. In fact it heard all frequnecies but focused on the most predominant (loudest).
As you slide the volumn weights towards the high frequencies the gaussian distribution wraps around to the low end of the frequency spectrum and the tone that your ear thought it was hearing (the high end), fades off into the distance. By this time though it has picked up the increasing volumn of the lower tones and is following them up the scale.
Repeat endlessley.
All this time we were watching a film of a ball bouncing up and Escheresque staircase and feeling like a bunch of laboratory mice.
--
John T. Nelson UUCP: sun!sundc!potomac!jtn Advanced Decision Systems Internet: j...@potomac.ads.com 1500 Wilson Blvd #512; Arlington, VA 22209-2401 (703) 243-1611
I tried this, on a programmable synth, and it don't work. What you get is kind of a Barber-Pole scale, but I can definitly recognise the roots. I tried it both starting on the root and ending on the root, and starting on the root and ending on the 7th, in the Major, Minor, and Minor Harmonic Scales.
What does seem to work is simply to use at least 4 seperate voices to gernerate independent, evenly spaced tones with increasing frequency. When a voice reaches an upper bound (the higher the better) set it back to something under 40hz. Also, non-linear (increasing) functions of freq. vs time seem to work better, but the programmablity of the synth hindered me from better exploration of possible functions.
Both of these sounds are intersting. If I ever decide to learn to program the audio portion of the Amiga maybe I'll writeup a quicky demo of these effects.
(Richard Sexton) writes: > There was a display at the Ontario Science center, ohh, 12 years or so > ago, about MC Escher, that had a ball bouncing "up" an ever increasing > staircase, with this tone, going up in pitch.
> It went up in pitch for the 1/2 hour I stood there. :-)
> Any clues ?
See Johann Sebastian Bach's "endlessly rising canon". This is a very old illusion, based on the fact that a note sounds very much like the same note in the next octave.
Display hack time, Leo? -- -- Peter da Silva `-_-' ...!hoptoad!academ!uhnix1!sugar!peter -- Disclaimer: These U aren't mere opinions... these are *values*.
I'm posting a Macintosh version of the Shepard Tone effect to [SUMEX]<INFO-MAC>. The program lets you go up or down forever, and includes an animated ball rolling around an endless staircase. See pages 717-719 of _Godel, Escher, Bach: an Eternal Golden Braid_ Douglas Hofstadter, Basic Books, New York, 1979, for a description of the sound algorithm.
--- David Phillip Oster -- This sentence is a life-like replica Arpa: os...@dewey.soe.berkeley.edu -- of one by Douglas Hofstadter. Uucp: {uwvax,decvax,ihnp4}!ucbvax!oster%dewey.soe.berkeley.edu
Followup to rec.audio, which is where this belongs.
In article <2...@gryphon.CTS.COM> rich...@gryphon.CTS.COM (Richard Sexton) writes: >Sonic holograms ? Yes, a friend of mine has a Carver as well. Mighty >impressive.
I borrowed one for a test listen. I found that it did make a slight difference in the sound, but only in a very small sweet spot, and not one that was uniformly better for all material. I was not impressed, even given the price of $100 (used).
>Plus, there is an audio illusion I've been looking for, for quite >a while now. Basically it is an ever increasing tone.
Piece of cake. The trick is to play sine waves at a certain note in all octaves simultaneously. Say you start at A. Then you begin with a mixture of A27.5, A55, A110, A220, A440, A880, A1760, A3520, A7040, A14080 and maybe even A13.75 and A28160 if your equipment is up to it. The relative volumes are higher in the middle and taper off toward the upper and lower registers.
Now, you increase the pitch of each wave slightly, and adjust the volumes so that the lower tones are a little louder, and the upper tones are a little softer, in order to keep the "center of gravity" in frequency space at the same place. Repeat this until you have "gone up" one octave; at this point you can delete the tone which is inaudibly high and insert a new tone an octave below the lowest one. Guess what? You now have exactly the same signal that you began with, and can start over. Repeat indefinitely.
-- Howard A. Landman {oliveb,hplabs}!intelca!mipos3!cpocd2!howard howard%cpocd2.intel....@RELAY.CS.NET "Lather. Rinse. Repeat."
In article <1...@sugar.UUCP> pe...@sugar.UUCP (Peter da Silva) writes:
>See Johann Sebastian Bach's "endlessly rising canon". This is a very old >illusion, based on the fact that a note sounds very much like the same note >in the next octave.
More specifically, it's a piece in Bach's _Musical Offerings_. Each of the pieces are intriguing in their own right. I'm not knowledgeable enough in music theory but I recently perused over a book that was devoted exclusively to anaylyzing _Musical Offerings_. Very interesting!
The piece starts on one key but after the piece nears the 'end', it has changed to another key, and the 'end' of the piece runs smoothly into the start of the piece, this time with the new key. The key goes on changing until you've reached the original key, and so on and so on and so on and so...
A similar work (without the key changes but with the tail -> head sort of loop) was done by Chopin. I can't remember what it was called, though it was a piano piece (big surprise! - for Chopin :-) If anyone is interested, I can dig it from my notes...
>-- Peter da Silva
-a.g. hirai "You have just begun reading a sentence which you have just finished reading." -- Eiji "A.G." Hirai @ Swarthmore College, Swarthmore PA 19081 | Tel. 215-543-9855 UUCP: {rutgers, ihnp4, cbosgd}!bpa!swatsun!hirai | "All Cretans are liars." Bitnet: vu-vlsi!swatsun!hi...@psuvax1.bitnet | -Epimenides Internet: bpa!swatsun!hi...@rutgers.edu | of Cnossus, Crete
In article <1...@sugar.UUCP> pe...@sugar.UUCP (Peter da Silva) writes:
>(Richard Sexton) writes:
>See Johann Sebastian Bach's "endlessly rising canon". This is a very old >illusion, based on the fact that a note sounds very much like the same note >in the next octave.
More specifically, this is a piece called "Canon per Tonos" and it's in J.S. Bach's _Musical Offering. The canon is able to repeat itself because Bach made the 'tail' notes of the canon flow smoothly into the 'head' notes of the canon. More importantly, the canon starts in the key of C minor but when we near the end of the piece, it changes to the key of D minor. So we keep on playing in the key of D minor but when we near the 'tail' again, it changes to E, and so on and so on... Eventually, it reaches the key of C minor, to start all over again!
Bach's _Musical Offering_ also contains other interesting pieces too. Check out Hans Theodore David's _J.S. Bach's Musical Offering_ to see how involved and beautiful this collection of musical delights is! The book is devoted exclusively to the analysis of _Musical Offerings_. Bery bery interesting...
Another piece which repeats itself is Chopin's _Mazurka in F minor_, opus 68 posthumous (1849). You can play this piece without end, though it doesn't have the neat key changes that "Canon per Tonos" has.
I posted a query for any pieces the net-readers know about that are similar to these, but the response so far has been under-whelming. Oh well.
-a.g. hirai "You have, of course, just begun reading the sentence that you have just finished reading." - Peter M. Brigham
-- Eiji "A.G." Hirai @ Swarthmore College, Swarthmore PA 19081 | Tel. 215-543-9855 UUCP: {rutgers, ihnp4, cbosgd}!bpa!swatsun!hirai | "All Cretans are liars." Bitnet: vu-vlsi!swatsun!hi...@psuvax1.bitnet | -Epimenides Internet: bpa!swatsun!hi...@rutgers.edu | of Cnossus, Crete
> A similar work (without the key changes but with the tail -> head > sort of loop) was done by Chopin. I can't remember what it was called, > though it was a piano piece (big surprise! - for Chopin :-) > If anyone is interested, I can dig it from my notes...
As I remember, the original question asked for an endlessly rising tone. These various plays on cyclic nature of the western scale achieve a similar effect, but are not quite what was asked for.
Western music is based upon a 12 tone system. These tones are sub- divided into sets of 7 notes which form scales (usually 7 notes). These subsets form alternative contours. When progressing through the keys rather than moving in one tone steps, the 5th member of a given scale forms the next most obvious key. By doing so the scale being changed to will contain only one note not found in its predicessor, which ex- plains why it is the next obvious key. This is layed out clearly for the ear in J.S. Bach's studies of the well tempered scale.
Taking this into account, it should be possible to derive any number of always rising progressions. Of course doing so in an artfull manner requires skill, insight, and talent. What I find fasinating about Bach's work is the precise control of multiple modes of the keys.
Interestingly enough, the well tempered scale is not true to the ear. IE: if I tune my guitar by ear to a given major scale, it will sound fine in that scale, and its cousins, but degrades with distance from the original root. Clearly the well tempered clavier (spelling?) is full of consistent distortions to make the circle of 5ths fit. At least I think this is so. Any knowlegable theory experts care to enlighten me?
In article <2...@crash.cts.com> hai...@pnet01.cts.com (Wade Bickel) writes:
> As I remember, the original question asked for an endlessly rising > tone. These various plays on cyclic nature of the western scale achieve > a similar effect, but are not quite what was asked for.
I am suprised that no one has cited the "Little Boy Suite" on this topic. I cannot remember the composer's name, although I seem to recall that he was French. This was one of the works composed with Max Mathews' Music V system; and, as I recall, it goes down, rather than up. Nevertheless, the principle is applicable in either direction.
The composition was based on a timbre whose Fourier spectrum was periodic. Thus, it could be extrapolated both above and below the limits of human hearing. One could then gradually lower the fundamental, creating the sense of a descending pitch. However, new partials would enter from above as others would drop off below; and the effect was one of an endlessly descending tone. (The dramatic effect was intended to be that of the dropping of the "Little Boy" atomic bomb.) I have heard this referred to as the "fencepost" effect, because it is like driving past a long row of fenceposts with new ones always entering the visual field and no end in sight.
In article <4...@venera.isi.edu> smol...@vaxa.isi.edu.UUCP (Stephen Smoliar) writes:
>I am suprised that no one has cited the "Little Boy Suite" on this topic. >I cannot remember the composer's name, although I seem to recall that he >was French. This was one of the works composed with Max Mathews' Music V >system; and, as I recall, it goes down, rather than up. Nevertheless, >the principle is applicable in either direction.
Jean-Claude Risset, in late 1960's, Bell Labs. He used this and similar effects in some other pieces, too (I think in "Mutations", but I don't remember this for sure right now).
As for mentioning this piece(s), I had an impression that wasn't the kind of "perpetuum mobile" the original poster was seeking.
--I am suprised that no one has cited the "Little Boy Suite" on this topic. --I cannot remember the composer's name, although I seem to recall that he --was French. This was one of the works composed with Max Mathews' Music V --system; and, as I recall, it goes down, rather than up. Nevertheless, --the principle is applicable in either direction. --...the effect was one of an --endlessly descending tone. (The dramatic effect was intended to be --that of the dropping of the "Little Boy" atomic bomb.)
Jean-Claude Risset, published on Decca 710810 "Voice of the Computer" 1970. (The piece is fine as music, too). --
Martin Taylor {allegra,linus,ihnp4,floyd,ubc-vision}!utzoo!dciem!mmt {uw-beaver,qucis,watmath}!utcsri!dciem!mmt m...@zorac.arpa Magic is just advanced technology ... so is intelligence. Before computers, the ability to do arithmetic was proof of intelligence. What proves intelligence now?
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