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Open one of the two source soundfiles by typing command - O. Type
command - C to bring up the Convolve dialog. Open the second of the
source soundfiles by clicking on the Pick Impulse button. Click Moving to have
convolution move through the second soundfile, otherwise this process will
convolve against a fixed segment of the second soundfile. Click Brighten to
avoid over-attenuation of high frequencies. Select Triangle in the Window:
popup menu to smooth the convolution. If you prefer an unsmoothed
convolution, select Rectangle.
Now set the Length Used: number. This is used to designate how much sound
gets processed in each block. You can treat this number like the decay time
of a reverb, because convolution has a sound which is like a very complex,
tuned reverb. A length of 0.1 seconds (100 milliseconds) is a good place to
start. For higher settings of Length Used:, the memory requirement increases
exponentially.
Now that everything is set, click Process. Because the gain in convolution is
unpredictable, save the new soundfile in a format with a large dynamic
range. When the Save Soundfile as: dialog appears, select a File Type: of
NeXT (.snd) and a File Format: of 32 Bit Floating Point. Click Save and wait.