[Clam-devel] Re: GSoC: Enhancing chord detection

[Roman Goj]

Hi again, sorry for a double post, but I have a correction:

On 5/28/07, Roman Goj <roman.goj at gmail.com> wrote:
> Ad 2. Well this was a failure :( Admittedly I did not spend as much time
> on this - I got too excited with the results from the first try (forgot
> to eat my dinner today... this is going to be an exciting summer ;) ).
> For this experiment I took 20s out of the example CLAM Annotator song -
> Debaser-CoffeeSmell.mp3 and tried decomposing it using mono-frequency
> gabor atoms and harmonic gabor atoms (with frequencies f0, 2*f0,
> 3*f0)... and mostly what I see in the results are notes right next to
> the notes that should be there (the right ones absent) - like in short
> time Fourier transform with too short a window - one sees the energy
> near one's notes, without being able to perfectly pinpoint the right
> ones... Well perhaps this is a bit inconclusive, since I didn't have
> enough time to let the scripts work longer on the signal, perhaps over
> the night better results will be born (all excited about tomorrow
> morning - I'll be dreaming in gabors tonight ;) ). But for now - this
> test is a failure :(

Correction - I must have been blind and deaf and extremely tired
yesterday (didn't seem to be like that yesterday though...)
...because, checking the results of the second try today morning I
find there's an almost perfect correlation between my results and the
song...

A longer - 3 hour trial of harmonic gabor atoms MP in 100 iterations
decomposing the first 20s of  Debaser-CoffeeSmell.mp3 resulted in:
97 atoms perfectly fitting the most striking notes in the signal (as
judged by both my guitar+ear and CLAM's Annotator :) )
3 atoms showing notes neighbouring the real ones, I think these ones
are wrong (unless here my ears can't here them - Annotator shows some
faint signs of the notes presence, but I suppose that's just noise in
both the algorithms?)

I could maybe post the plot when I manage to setup my wiki account...?
:) (perhaps my account creation problems have something to do with the
new servers?)

Also - I have some ideas that should make the algorithm much, much
faster and that still in Matlab, so it should work faster when
compiled... so with this and the corrected results I dare declare both
my trials succesful! :)

I'm very sorry for the first misleading post - I didn't check the
first results thoroughly enough yesterday :( but I guess it's better
this way around than if I first said everything worked great...? :)

Roman