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Re: Lang's log scale sonograms

Subject: Re: Lang's log scale sonograms
From: Walter Knapp <>
Date: Fri, 14 Mar 2003 00:23:58 -0500
Steve Pelikan wrote:
> Lang et. al.:
> 
> At http://math.uc.edu/~pelikan/Dora/sonos.html
> 
> is an example of two sonograms produced from the same sound file.
> The "coarseness" of the log-scaled picture can be fixed by using a larger
> blocksize when doing the transforms --- as it was several pixels get the
> same power data at the lower frequencies.

I mentioned to my son about using a frequency variable FFT blocksize to 
help get around these problems. He figured it would not be hard to do 
static using a multipass analysis, but the multithreading to get it to 
run in realtime would challenge even his dual 1ghz G4. He did not see 
any problem to doing it in theory.

> And Walt's right (what else is new?) that the Dora program(s) are written
> in Java so that, in principle, they can run on Window, Unix, Linux, and Mac.
> I've only tried the first 3. If someone wants "help" getting java installed
> and
> Dora running, I'd be happy to trade a few emails  on
> the subject.

I'll see if I can get my son to run the program on his dual G4 running 
OSX. He's been writing a Java program these last few weeks so is all set 
up. It'll depend on how much time he has.

> On the subject of music vs. natural sounds, I completely understand Walt's
> sense that
> music (and the $$ associated with recordings of same) has nearly completely
> determined
> the course of development of recording aesthetics, technique and equipment.
> Probably not in the best
> interests of natural sound recordists. On the other hand, one of the best
> "ear" birders I
> know has perfect pitch and is very effective in communicating about bird
> sounds using
> the language of music.

I'm actually more at odds with sound tests that are appropriate for 
music, but may be far less appropriate for sounds in general. It's very 
hard to get good general analysis software as a result. On top of that 
many of the measures still commonly used were developed for analog tape 
or phonograph records, a whole nother problem...

Music is a single way of organizing sounds. As we think of it, it's not 
even universal in human society. And certainly not in the natural world. 
The natural world has perfect pitch too, just does not match our 
cultural rules.

I avoid describing calls by musical notation. They don't exactly fit 
that and doing so will cause our minds to reprocess what we actually 
heard to fit what we think we should have heard. Try to avoid tying 
natural sounds to music so you can hear them as they are.

The whole craft of recording the highly stylized calls of humans (music) 
in acoustically simple environments (buildings) brings people to using 
techniques that may be inappropriate for the infinite space and 
complexity of the natural environment. Or the acoustic projection 
techniques of animals. Pick up any book on mics and mic technique, and 
only the general stuff will help you for nature recording. So much of 
which mic is good bad or indifferent will be related directly to music 
too. All we can do is go back to basics and work out our own methods.

Walt




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