Recording a convolution reverb
Capturing a space's reverb using convolution
In audio signal processing, convolution reverb is a process for digitally simulating the reverberation of a physical or virtual space. It is based on the mathematical convolution operation, and uses a pre-recorded audio sample of the impulse response of the space being modelled. To apply the reverberation effect, the impulse-response recording is first stored in a digital signal-processing system. This is then convolved with the incoming audio signal to be processed.
The primary goal of a convolution reverb is to sample real spaces, in order to simulate the acoustics of the sampled space.
Using a small Genelec monitor I played a sine sweep (12 sec, 30 sec, 60 sec) in the 6-storey stairwell that is used as a fire escape at London College of Communication. The tall enclosed nature of this space combined with hard concrete surfaces and lots of stairs create a unique and spacious reverb. 2 Fostex digital recorders were used, one to play back the sine sweep and one to record in both mono and stereo.