Retrieving frequencies from music


I'm working on a program that visualizes music using an oscilloscope and a

"frequency-spectrum". I got the oscilloscope up and running now, but I'm

kind of struggling with the frequencies. I know it's possible to retrieve

them using a Fast Fourier Transform, but I don't know anything about how to

interpret it. I'm using buffers that contain 1024 samples of music (that is,

4096 bytes for 16-bits, stereo sound and approx. 23ms at 44100Hz sampling

rate). If I got it right, the FFT will give me the amplitudes of all sines

that have frequencies divisible by 43Hz. But how about frequencies that

aren't divisible by 43Hz??

Another option might be the use of filters, a low-pass filter for every

thousand Hz.. I don't know what technique is used by e.g. WinAmp, maybe

someone can tell me how to get some more information on this matter..?

I'm also looking for characteristics in sound... What are the things in

sound that are specific for sound? I mean things like tempo, volume,

frequency.... but also timbre & pitch, maybe it's even possible to retreive

certain chords from music.... But I guess it's all pretty hard to do....

Anyway, if there is ANYONE out there who knows more about this stuff, or

anyone who's interested.... please share information with me, I will be very


Many thanks,

Robert de Groote.


  • Hello !

    I don't know wheter you've already found the answers to your questions, anyway ... I'm working on a similar problem, and think I found something that could be useful for you too. Write me:

    Szocs Geza, UBB-Cluj.

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