Testing different frequencies of popular songs

[kihatan]

For this year's science fair project, I'm trying to make frequency graphs of certain frequencies in popular songs, and am going to compare them to see if music of same genre have similar characteristics. To do this, I need a program that can take a certain frequency, and graph its changes over the entire song. This would be preferably for seven or eight different frequencies. Thanks.

[DVDdoug]

I'm not sure what software is available, but I might be able to get you started.

A Spectrum Analyzer or Real Time Analyzer (RTA) will show you the frequency content of a sound, but these generally only show the instantaneous frequency content at any moment, rather than for the whole song. A quick search turned-up this FREE spectrum analyzer.

You might be look into Spectrograms and Spectrographs, which show frequency content over time.

There are programs like Matlab (and there are FREE Matlab clones) that should do just about any kind of analysis & graphing you want. But, I've never used Matlab and I have a feeling that it might take a LOT of study if you are not already familiar with it. if this was a university-level project, I'd say that's the way to go, but It's probably too much work for a science fair project (and you might need to know something about Fourier Transforms). Excel can do Fourier analysis, but you'd have to get the WAV file data into a spreadsheet, and at 44,100 samples per second, you'd have an unmanagable number of cells.

[steve]

What sort of output are you looking for? Something graphical or a table of numbers or something else?

Will something like this do?

firsttrack004.png (10.99 KiB) Viewed 572 times

This is a narrow band of frequencies centred on 500 Hz from a recording of "Reach Out I'll Be There" by "The Four Tops".

This was produced with Audacity 1.3.13 by applying the following code in the "Nyquist Prompt" effect:

Code: Select all

(setq f0 500)

(let ((s (if (arrayp s)(mult 0.5 (sum (aref s 0)(aref s 1))) s))
      (step (truncate *sound-srate*)))
   (mult 2 (snd-avg (highpass8 (lowpass8 s f0) f0) step step op-peak)))

The first number (500) sets the centre of the frequency band.
To produce an output similar to that above, convert the track to mono (if it is stereo) from the "Tracks" menu, then apply the "Nyquist Prompt" (Effect menu) with this code.
When it has finished processing the track will shrink to a tiny fraction of its original size (one second of audio becomes one sample), so use the "Zoom to all" button to zoom in. For a dB scale on the left, click on the track name and select "Waveform dB".
Zoom in as required vertically by clicking on the vertical scale and dragging across the height that you want to view. Right click on the vertical scale to zoom back out.

This "graph" could also be printed by selecting "Print" from the File menu, but you loose the vertical scale if you do that, so a screenshot may be better. There is a screenshot tool in the "Help" menu.

[kihatan]

I was looking at getting something graphical, but now am trying to figure out how to compare frequency spectra. I'm using UltimaSound, but if anybody has any idea how to compare frequency spectra, help would be greatly appreciated.