FabFilter User Forum

WaveLab Pro - processing with Pro-Q 2 & 3 adds silence to the end of a file

I have been noticing Pro-Q 2 and 3 will add silence to the end of a file post-processing in WaveLab Pro 9.5 (I am on 9.5.50).

As an exercise, I performed this on a 100ms audio file, and the result was a 271ms audio file (ie. 171ms of silence was added by Pro-Q).

This is not something that I have experienced with other plugins.

James Langford

Hi James,

Pro-Q 2 and 3 report a "tail size" of 8192 samples: this is to accommodate the possible length of a filter response. This explains the 171 ms increase in file length.

If we wouldn't do this, the host could cut off the response of the plug-in just after the incoming audio which could result in an audible click depending on the type of filtering that is performed.

I hope this explains things for you!


Frederik (FabFilter)

Hi Frederik,

Yes, this makes sense. After posting, I was wondering whether it might be something like this.

Thanks for the explanation!

James Langford

I'm using ProQ 3 hosted by Sound Forge 15. Pro Q 3 is adding 340 ms of silence to each filtered file. This is a problem as many of these are being concatenated at run-time and ducking is dependent on file length.
Could you trim back to original length or does the plug-in not have that information?

I really like the result that I am getting with ProQ 3 (VST3 64 bit) but I don't want to have to clean up 800 files and currently the trim function isn't supported by the batch converter of SF15.

David Thiel
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