[music-dsp] Splitting audio signal into N frequency bands

[Thilo Köhler]

Hello all!

I have implemented a multi-band compressor (3 bands).
However, I am not really satisfied with the splitting of the bands,
they have quite a large overlap.

What I do is taking the input singal, perfoming a low pass filter
(say 250Hz) and use the result for the low band#1.
Then I subtract the LP result from the original input and do
a lowepass again with a higher frequency (say 4000Hz).
The result is my mid band#2, and after subtracting again the remaining
signal is my highest band#3.

I assume this proceedure is appropriate, please tell me otherwise

The question is now the choise of the filter.
I have tried various filters from the music-dsp code archive,
but i still havent found a satisfiying filter.

I need a steep LP filter (12db/oct or more),
without resonance and fewest ringing possible.
The result subtracted from the input must works as a HP filter.

Are there any concrete suggestions how such a LP filter should look like,
or is there even a different, better way to split the audio signal
into 3 bands (or N bands)?

I know I can use FFT, but for speed reasons, I want to avoid FFT.

Regards,

Thilo Koehler