pitch tracking at very low (and sub-audio) frequencies

Mar 1, 2011 at 4:39am

pitch tracking at very low (and sub-audio) frequencies

i have an audio signal coming into max that i want to use to control other things. it’s a slightly mellowed-out squarewave that varies between about 100hz right on down to 0hz. I need to be able to detect the frequency.

I’ve been experimenting with jehan’s pitch~ without much luck — it doesn’t seem to be able to make much sense out frequencies in this range. Anybody have any ideas?

#55255
Mar 1, 2011 at 4:52am

maybe a bank of reson~ objects?

#198873
Mar 1, 2011 at 5:25am

This kind of low tech but if it’s really just a variant of a square wave and you have a guarantee of only 0 only twice per wave , why not just measure the zero crossings?

#198874
Mar 1, 2011 at 6:04am

hmm yeah. what object can you use for that?

#198875
Mar 1, 2011 at 7:25am

[zerox~]

#198876
Mar 1, 2011 at 11:21am

a cheap and nasty solution perhaps..
less reliable for higher frequencies of course.

– Pasted Max Patch, click to expand. –
#198877
Mar 1, 2011 at 5:32pm

[zerox~] doesn’t seem to work too well because i have to turn the signal vector up ridiculously high to get any usable data. kthozoid i’ll check out your method.

#198878
Mar 1, 2011 at 6:07pm
– Pasted Max Patch, click to expand. –
#198879
Mar 1, 2011 at 6:13pm

(the minimum object~ and the three divisions aren’t really necessary.

#198880
Mar 3, 2011 at 6:20pm

wow, thanks audiomatt. brilliant solution. This works very well.

#198881

You must be logged in to reply to this topic.