[Clam-devel] [PATCH] tonal analysis with configuration - episode 2

[Roman Goj]

Hernán Ordiales wrote:
> On 7/7/07, Roman Goj <roman.goj at gmail.com> wrote:
> [snip]
>> Btw. are there any "dead simple" test signals for CLAM? The included
>> songs are nice, but I'd love to have something even simpler and very
>> obvious for testing and with graded complexity... i.e. play a single
>> note... play "happy birthday" with single notes... play "happy birthday"
>> with chords and single notes... play "happy birthday" with a simphony
>> orchestra and finally... make a jazzman play "happy birthday" ;) And of
>> course a woman and a man to sing it... I know it's best to present CLAM
>> with some nice complex sounds but it's easier for testing and learning
>> about the algorithm (for me or future clam users) to have simple signals
>> (I guess...) (also my supervisor pointed out, while I was doing a
>> presentation on analysing music with STFT, Constant Q, Matching Pursuit
>> that I should really be using a clean Wave file for testing how the
>> actuall algorithm works, not an mp3... I'm definitely not an expert in
>> how mp3s work, but according to my supervisor one might "tune in on the
>> algorithm parameters" for a specific encoding scheme, so it might be
>> better to use waves to be general... what's you opinion on this?) ...So
>> could I add myself a future TODO - record/find in the public domain
>> these simple signals or are they already there or should I not waste my
>> time on it anyway?
> 
> i think CLAM only provides mp3 only as matter of space... anyway a
> couple of short examples in wav or links wouldn't hurt
> 
> maybe look here? http://freesound.iua.upf.edu/

Thanks, great! I should've found that while I was doing my MP spike,
would've come in useful :)

I also like the sounds here - single notes sampled in really big files:
http://theremin.music.uiowa.edu/MIS.html
:)

> I can't see your point clearly, you also could tune an algorithm to a

well... no wonder you couldn't, because I didn't see it clearly either,
so I couldn't explain it clearly ;)

Point is (I suppose...) something like this - compression algorithms are
(or should/could be) based on psychoacoustics - they should rip all the
unnecessary info out of the wave - all the sounds one wouldn't hear
anyway, but could spoil or help detection algorithms?... I'm not sure it
really matters though... :) (or,for that matter, that mp3 can really do
any complicated stuff) Maybe I'll test it sometime? chord extraction on
a wave and then on an mp3... hmm... we'll see if my supervisor had a
point ;)

Anyway I really know little 'bout compression (ok, I know mp3 filters
the higher frequencies above some threshold, rude if you aks me ;) ), so
I can only keep guessing :)

> fixed example... I think main problem it's about lossy property of
> mp3... (basically you're losing spectra and resolution... and if you
> chain encodings would be worst and worst)
> 
> [snip]

cheers,
roman