Examples of Complex Filters

Multi-pass processing

In some cases, repetitive declicking yields improved results when compared to single-pass processing, especially for recordings with very large click intensity.

In particular, the following three-pass processing is quite useful:

1. Remove large scratches by declicking the signal using the large value of the maximum length of detection alarms (e.g. 80) and a large or very large value of the detection threshold (e.g. 5.0).

2. Remove the remaining (usually small) scratches and clicks by declicking the signal using the small value of the maximum length of detection alarms (e.g. 20) and a normal or small value of the detection threshold (e.g. 3.5).

3. Denoise/dehiss the results obtained at the second stage.

We recommend the smoothing and postfiltering actions be switched off during the first two stages of processing.

Reverse time processing

For certain classes of disturbances, backward time processing gives better results than forward time analysis. For example, clicks with soft (round) front edges and sharp back edges usually fall into this category (click geometry depends on many factors such as the recording and mastering technology, properties of the recording medium, playback technique, etc.). Another advantage of reverse time processing is due to the fact that it tends to cope more favorably with transients occurring each time a new sound starts to build up.

When it comes to dehissing/denoising, time-reversal gives no processing advantages so the recommended order of processing is: Reverse, DeClick Plus, Reverse and DeHiss Plus or DeNoise Plus.