Maximum amplitude of a FFT signal…HELP!!!
I want to analyze an audio signal in real time with MAX/MSP 5, using fft (or better pfft). What I want to do is to find the maximum amplitude value (in dB) of the fft signal, and the relative frequency.
Has someone already created a similar patch?
I am able to get the amplitude and the frequency values but I am not able to find the maximum…The amplitude (converted by cartopol) is a signal….how can I get the maximum of a single signal?
I attached 2 patches I created. Feel free to modify them!
Thanks in advance
You are trying to achieve something that isn’t impossible but not easy either. There’s a few options
1. get everything out of the signal domain in order to perform calculations on lists; this is rather dirty
2. program your own objects in C or mxj~ that do what you want
3. have a look at FTS from ircam, which is designed for doing these type of things.
thanks a lot for the answer.
I am trying to write an object using the MAX SDK.
Anyway, why do you think is "dirty" to use lists of numbers coming out the fft?
What is exactly FTS? I am searching in google but I ask you please to you explain exactly what it is and why it can help me.
Thanks a lot!
|What is exactly FTS? I am searching in google but I ask you please to you explain exactly what it is and why it can help me.|
Sorry, that’s a mistake, it’s FTM, an extension to max/msp.
Dirty because, you can never be sure of receiving a list for every analysis frame, and there not really a method for collecting a number of values into a list in the first place. You could use poke~ and uzi the values out, but, yuck.
Thanks a lot.
Has someone else other suggestions?
Thanks in advance
read the manual at the pfft~ tutorial (26), heading called:
cartesian to polar conversion.
it is all there.
Quote:Has someone else other suggestions?
Thinking of it a little longer, yes. Jitter.
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Record the sonogram in a jitter matrix, then explore the sonogram, find maximums, etc.