Ok, so now I have modified the FHT code a little bit.
I hooked the audio signal to A1, and it turns out that most of the
unwanted signal is being leaked to A0.
So I thought why not take the leaked signal in A0 and remove it from A1 as noise cancellation.
After testing out all of the Analog inputs I noticed that the Unwanted signal is being leaked throughout all of the
analog inputs, but the music itself is less noticable the further away you go from the noise reference input.
So I connected the Audio signal to A5 instead, and use A0 as noise reference.
Works pretty good

Ok, now I will create a new thread regarding other things about FFT.
Once again guys, thank you a lot!
The cluttering is fixed Magician

I attached my sketch so you can try it out for yourself
