Forum

Graphic eq 31

Hi guys!

It’s possible converting FFT signal to 31 graphic eq, I need analize audio track and convert to 31 graphic eq to visualitzer the bars.

Try Resample, or just change the spread count on the fft node itself

You can explain or put and example please. I don’t understand the method.

… no text …

jordi1.v4p (4.4 kB)

Good. Io. I understand that you said.

But If I use a simple sinewave generator tone not correspont with de 31 band.

I use the simple feedback trainer to generate a tone. And check.
http://sft.sourceforge.net/

jordi1.1.v4p (8.0 kB)

Are you taking into account the sampling rate of the AudioIn node ?

No, I use 44100hz this is default value. An my sound card is configured to this sample.
I should do something with this value?

You are bumping into the fact that the fft is linear and a 31 band EQ or in your case spectrum analyser is 1/3 octave and logarithmic. You will need to recombine the fft bins into 31 new bins but not linearly.

good Sunep.

I found this information in vux-doc to extract the freq of each fft bins.
If I understand.
Sample Rate 44.100hz
FFT size 512

The FFT bin number 1
1* (44.100/512) = 86,13hz

FFT bin number 20
20 * (44.100/512) = 1722,65hz

It’s correct to separate the fft bin with this parameter and decide the bin 20, 21, 23, 24 represent the 1khz octave.

I understand to the sunep. But the problem it’s i haven’t an idea to make the recombine fft bins into 31 new bins but not linearly.

Can I help me?