is it possible to remove correlation between volume and spectrum in getAudioSpectum()?

Question

I've been making a music game in which I use myAudioSource.getSpectrumData() to get spectrum. But I noticed that the spectrum directly depends on the volume of the sound, in direct proportion: the bigger volume the bigger spectrum. And that brings problems like: zero volume makes game to stop, big volume makes it too sensitive and to work incorrectly. I've tried to normalize the spectrum but it's correlated anyway, just in [0,1]. Make some transformations with volume? It will correlate anyway.

Is here a way to get spectrum data or transforms it in some way so that it will be independent from volume?

For example, if a song is too loud so the biggest part of values from spectrum will be in [0.9, 1] for normalized spectrum data. If the same song make quieter, it will be [0.1, 0.3] interval.

Code:

private AudioSource src;

private void Start()
{
     _samplesArray =  new float[64];
}

private void Update() 
{
      // Every frame get spectrum into _samplesArray with size 64
      src.GetSpectrumData(_samplesArray, 0, FFTWindow.Rectangular);
}

Answer 1

That makes totally sense:

• If the volume is low then on the entire spectrum you get lower values / ranges / peaks
• If the volume is high then you can expect the entire spectrum to move to a higher range

You can / have to simply normalize the spectrum using e.g.

using System.Linq;

...

_samplesArray = _samplesArray.Select(s => s / src.volume).ToArray();

or without Linq maybe better to understand

for(var i = 0; i < _samplesArray.Length; i++)
{
    _samplesArray[i] /= src.volume;
}