For more information about frequency-warped FIR convolution, look here.

This module performs warped convolution of the currently selected waveform with the waveform (in this case it is better to say "coefficients") actually present in the Windows Clipboard. This means that, before using this module, You have to load in the Windows Clipboard (not in the CoolEdit Clipboard !!!) the Warped Impulse Response that You want to use as a filter. See later for instructions on how to convert a "normal" IR into a "warped" IR, that is, how to compute the WFIR filtering coefficients which approximate a given FIR.

After copying the WFIR coefficients to the windows Clipboard as a WAV file, pressing the "Convolve with Clipboard"  button, the Following dialog Box appears:

In this case, as it is shown, we want to convolve the stereo input of the current audio data with both the channels of the IR, which are used as simmetric cross-talk-cancelling filters.

When OK is pressed, tha standard Progress Meter of CoolEdit appears, until the convolution process is finished. At this point the final dialog box is displayed, reporting statistics about the warped convolution process:

Pressing OK, the new convoluted waveform is displayed.

For creating pre-warped IRs, You must first load onto the clipboard the original FIR response to be warped. Then create an empty waveform, generate in it a piece of silence of reasonable lenght (usually longer than the original FIR), and edit it in such a way that the first sample is maximized (made equal to + 32767).

At this point, warp-convolve the newly-generated waveform with the clipboard, but assigning a negative value to the warping coefficient. The result is the set of filter coefficients which mimic the original FIR response, when employed in a WFIR processing with positive warping coefficient. You can usually cut the tail of the warped IR, as it contains details related to the high-frequency response, which are thus "smoothed away".