Re: Software for chord identification

[Eric Jacobs <ericj@xxxxxxxxxxxxxxxxxxx>]

I play a few instruments casually, but I don't consider myself a 
"musician" (I don't compose, and I don't have the skills to 
improvise well).  I have a reasonable ear, but I don't have perfect 
pitch.  I can catch the obvious differences - gross pitch errors - 
but more subtle errors are harder for me.  I make it a point to
listen to live music as much as possible, and I keep a few 
instruments around for checking sounds when I'm not sure (piano, 
drum, guitar).  But if I had some tools to augment or validate 
my ears, that would be even better.

Besides pitch and tempo, what are the other sonic markers to listen
for?  I listen for timbre (harmonics) and sometimes percussion is 
helpful (does it really sound like a snare or a cymbal?).

Again, I would love to make this a bit more scientific if I could.

Eric


-----Original Message-----
From: AUDITORY Research in Auditory Perception
[mailto:AUDITORY@xxxxxxxxxxxxxxx]On Behalf Of robert gjerdingen
Sent: Wednesday, September 07, 2005 4:05 PM
To: AUDITORY@xxxxxxxxxxxxxxx
Subject: Re: Software for chord identification


On Sep 7, 2005, at 5:21 PM, Eric Jacobs wrote:

> If I know what chord is being played (call this "actual chord") - and I
> do know what chord should be played (call this "ideal chord") - I can
> adjust the recording speed as required to reproduce the ideal chord.

Eric,

	I agree with Leon that "chord" may not be the best entry point to 
determine original pitch and therefore turntable speed.  Since chords 
are aggregates of pitches, and since knowing the "ideal" chord means 
knowing the ideal pitches, and since early recordings strongly 
foreground the vocalist or soloist, it would probably be sufficient to 
isolate a known "ideal" pitch and run it through a 
fundamental-pitch-extraction algorithm.

	While it might be possible to have a high degree of confidence in the 
ideal pitch of early classical instrumental recordings, confidence 
would be much lower in popular or classical vocal recordings.  In both 
realms pitch was often adjusted up or down for the comfort (or vantity) 
of the singer.  Nonetheless, if you really do know the ideal pitch, 
then the degree of error in pitch determination would probably be less 
than for other measures (e.g., vibrato rate).  On a different tack, if 
your recordings are of dance music, you might be able to use 
high-confidence recordings (e.g., movie soundtracks) to estimate what 
the Italians once called the _tempo jiusto_, or the "right tempo" for a 
given genre of dance (e.g., foxtrot, tango, etc.).

	Currently the very best software for comparing the actual pitch to the 
ideal pitch is known as a musician :)

Bob Gjerdingen
Northwestern Univ.