Deconvolution

Hi all,

I’m in desperate need of help. I’m trying to deconvolve a 20Hz-20Khz sine sweep impulse from and Impulse Response recording of a concert hall so I can isolate the reverberation and convolve it with dead sounds such as a DI guitar.

Ive been trying to build a convolution filter similar to the ‘forbidden Planet’ patch that can be found in the examples folder under ‘FFT-Fun’ but I don’t know what I need to do. I need to somehow filter out the sinesweep whilst in the frequency domain but I’m not sure how to do this in max. Apparently to do this requires a ‘deconvolution filter’ which should be an inverse of the sweep impulse I used when recording the IR (which went from 20Hz -20KHz in 15 seconds) . I tried using a Line~ object to generate a ramp from 20 to -20,000 and then used this to scale the spectral output of an FFT but this didn’t remove the impulse.

Does anyone know how this can be done?

Andy