Re: [music-dsp] Pointers for auto-classification of sounds?

2012-06-13 Thread Charles Turner
On Tue, Jun 12, 2012 at 2:48 PM, douglas repetto
doug...@music.columbia.edu wrote:
 I just tend to get over-critical of the claims people make about what
 they're doing. So much of the intersection between science/math/art/music is
 over-hyped that I've developed some sort of hype allergy.

 And because I'm a nerd I get all worked up about
 the imprecision of the language used to talk about these things in the arts.

 Sorry for being such a nerd, I'll stop spamming the list now!!!

Hardly spam:

The work, as Morton Feldman once said in a somewhat different
context, rhapsodizes its own construction, exalts the intricacies of
the structure through which it has acquired existence. Instead of
revealing such properties as linear continuity, thematic and motivic
development, formal cohesion, etc.-properties to a large extent
jeopardized by the disappearance of a conventional syntax-the work
reflects upon its own constitution. It is not surprising, then, that
many composers establish systematic scaffoldings of great complexity
on which to build their music, feats of dazzling virtuosity possessing
considerable interest in their own right. The formal properties of the
work become its true subject matter and thus a topic of primary
interest. This explains, I think, why there is a tendency for each new
work to have a system uniquely its own. This is perhaps overstated,
yet if one thinks of a composer like Stockhausen, or even Ligeti or
Xenakis, one sees that it touches upon an important facet of recent
compositional thinking. The construction of the system has itself
become an essential and inseparable component of the creative act.

Robert Morgan, _On the Analysis of Recent Music_, 1977
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Re: [music-dsp] Pointers for auto-classification of sounds?

2012-06-11 Thread Charles Turner
Well! An embarrassment of riches: enough for a graduate seminar at a
non-free university... ;-)

Thanks everyone who kindly contributed to this thread. There's a
summer worth of insight and information here, so rather than make
superficial comments, I'll return when I better understand my problem.

Ross pretty much guessed my interest. Trying to see whether it's
possible to automate the exploration of the parameter space of a
synthesis algorithm. Imperative to something like that would be a
procedure to analyze large quantities of sound data. Hence timbre
classification. Of course, the process could be really simple:
eliminating the settings that produced zero output, or immediately
went into self-oscillation. But who knows where the line between too
many to audition and convincing timbre classification lies?

I did manage to find prior work in this area. Bill Tozier pointed to
the Humies:

http://www.genetic-programming.org/hc2011/combined.html

One of the winners gave me the term EvoMusArt and some searching on
SpringerLink led me to papers. I've collected some here if anyone's
interested:

http://vze26m98.net/music-dsp/

(I don't think any of these were behind a paywall.)

I liked Colin Johnson's paper johnson-2006.pdf, though in general I
found most of this work disappointing from a musical perspective.

Best wishes and thanks again!

Charles
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Re: [music-dsp] Pointers for auto-classification of sounds?

2012-06-11 Thread Charles Turner
Another paper: Palle Dahlstedt's Creating and Exploring Huge
Parameter Spaces: Interactive Evolution as a Tool for Sound
Generation from the 2001 ICMC:

http://quod.lib.umich.edu/i/icmc/bbp2372.2001.006/1?view=pdfsize=100
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Re: [music-dsp] Pointers for auto-classification of sounds?

2012-06-11 Thread Charles Turner
Hahaha!! I had exactly the same experience in 2004 with a MSP patch I
made. I finally generated one fantastic sound, and on the next
compilation of my external, I couldn't recreate the sound with the
same GP data. The MXO went the way of Metrowerks and the PPC...

I do have a different thought now, and an interest to return to the
process, but we'll see.

On Mon, Jun 11, 2012 at 1:06 PM, douglas repetto
doug...@music.columbia.edu wrote:
 I ended up with really simple things like is the signal non-zero? is there 
 any variation in the amplitude?

Yeah, these are pretty useful metrics, always worth keeping in mind.

Best, Charles
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Re: [music-dsp] Pointers for auto-classification of sounds?

2012-06-11 Thread Charles Turner
On Mon, Jun 11, 2012 at 2:32 PM, Phil Burk philb...@mobileer.com wrote:
 Wind was howling and rain was generating grains of sound before life even 
 evolved.

I agree with Phil here. I started with a single sine period and
evolved stuff that would deform it:

http://vze26m98.net/music-dsp/philthomson-01.png

C.
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Re: [music-dsp] Pointers for auto-classification of sounds?

2012-06-11 Thread Charles Turner
On Mon, Jun 11, 2012 at 2:35 PM, douglas repetto
doug...@music.columbia.edu wrote:

 Let's hear it!

OK. Perhaps haven't stood the test of time as well as your sound, but
it came out of nowhere, and I loved the appearance of the waveform:

http://vze26m98.net/music-dsp/chp%20g%2002.png
http://vze26m98.net/music-dsp/chp%20g%2002.aif

and another:

http://vze26m98.net/music-dsp/my0-1.png
http://vze26m98.net/music-dsp/my0-1.wav
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Re: [music-dsp] Pointers for auto-classification of sounds?

2012-06-08 Thread Charles Turner
On Fri, Jun 8, 2012 at 1:56 PM, Thomas Young
thomas.yo...@rebellion.co.uk wrote:
 You haven't really explained which aspect of the timbre you want to use to 
 organise the sounds

Thanks. Very useful question. I'll pursue it.

Bon ouikend!

Charles
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[music-dsp] [OT] Rebecca Kim contact info?

2012-03-07 Thread Charles Turner
Hi all-

It occurred to me that someone here might know how I can contact
Rebecca Kim. I like to speak to her about the work she did on this
presentation of _Bohor_, the electro-acoustic work by Xenakis:

http://www.music.columbia.edu/masterpieces/notes/xenakis/index.html

If anyone has any leads, please contact me offline.

Thanks!

Charles
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Re: [music-dsp] Boulez

2012-02-25 Thread Charles Turner
On Feb 25, 2012, at 6:34 AM, Andy Farnell wrote:

 And whereas I do agree with Pierre Boulez here, maybe it
 is misguided to turn to reductionism and simplicity for
 their own sake. It may be equally hopeless to embark
 on a quest for authenticity this way. 

Hi Andy-

I should apologize for hastily listing the publication date of the book. The 
book collects his Darmstadt lectures from 1954-56, so it comes from a much 
earlier time. I don't think Boulez would have changed his mind on things 
though. Sounds like you come from a much more Schaefferian era.

Isn't the point not to take sides, but recognize the tension? Cultures that are 
busily exploring harmonic relations, haven't simultaneously plunged deep into 
the world of rhythm. Music is just too big a subject, and some of its 
properties exist in a dialectical relation to others. Although we all enjoy a 
sweet dessert, we don't put sugar in everything. (Unless you're the Nestle 
company!)

My point was that the checkpoint raised by callbacks feeding a sample buffer 
may come from resistances outside the technical world. Boulez sees timbre as 
the enemy of harmony. Could very well be that the callback is the result of a 
cultural outlook, and not the result of engineering design…

Best, Charles

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[music-dsp] Bandlimiting, Aliasing and Reconstructed Signals

2010-12-23 Thread Charles Turner
Happy Holidays Everyone!

I wanted to ask a question provoked by reading the SuperCollider Users' mailing 
list, which had me thinking I didn't understand the underlying concepts that 
were being discussed.

I went back and looked at stuff like Hamming's _Digital Filters_ and 
Oppenheim's _Signals and Systems_, although I'm greatly challenged by the math 
most of the time. Also, the discussions of sampling theory are just that: the 
authors are happy to shift back and forth from A-D and D-A to clarify a 
general theory, but as I'm interested in SYNTHESIS, taking away the finer 
points of signal reconstruction isn't always easy.

Here's my limit case: let's assume some typical laptop with CD-quality sound 
generation capability with a sample rate of 44.1khz and sample size of 16 bits. 
I create a sinusoidal waveform on the computer with a period of 4,410hz. I 
choose to create this waveform by feeding 4,410 divisions of the unit circle 
into a sine function. In other words, I calculate a unique value for each 
sample of the period at the sample rate of the laptop's D-A converter.

As this waveform is sent out the DAC, I assume it's subjected to a zero order 
hold of approximately 0.023 milliseconds. The DAC may also do it's own 
filtering of the signal before going out to a set of speakers.

My questions are:

1) Is the synthesized signal aliased? If so, how can we anti-alias it?

2) Is the signal band-limited? If not, do we want it to be, and how do we do it?

I'd also ask the same question about a similarly synthesized square wave. That 
may seems a bit simple, but there was the assertion on the SC-list that 
smoothing (I think that was the word) helped a loudspeaker figure out where 
it needed to be at a given point in time. I understand generally the point the 
poster was making, but isn't this a slippery slope? Not all speakers are 
designed with the same frequency response, so unless we tailor waveform 
synthesis to the specific characteristics of a loudspeaker, aren't we in danger 
of smoothing either too much or too little?

Also, a square wave is a square wave: it has sharp transitions. What timbral or 
spectral components of a square wave are intrinsic to its waveform, and what is 
introduced by a particular DAC and speaker combination? Or in other words, is 
the acoustic result of a synthesized square wave its resultant output, or is it 
something that sounds good?

Comments, links and/or laughter welcome.

Thanks, Charles

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