FabFilter

Hi,

I have found a strange behavior with the Pro-Q3 with a Low/High Cut band in Brickwall mode.

To replicate this, use any saw wave for example, with shortest attack and release so there is no tail in the source audio. Then put a Pro-Q3 on it and set a Low Cut at any frequency in Brickwall mode. You will hear a short ringing at that frequency right after the source file is done playing. You can accentuate this issue if you put a distortion plugin after, as it will increase that ringing's volume.

In my testing I used a sawtooth wave on F2 and the Low Cut frequency set at 179Hz.

If you change the Pro-Q3 to linear phase, you will start hearing this ringing slightly before the audio begins. The higher the linear phase quality, the longer the "pre-ringing".

I have observed this issue in both Cubase (vst3 version), and Ableton Live 9 (vst2 version) - although I did more extensive testing in Cubase.

Anyone else encountering this behavior?

I just saw that some of this was talked about here www.fabfilter.com/forum/3330/what-exactly-is-pro-q3-brickwall-doing#comment0

In my case it was significant enough that I wasn't understanding at first why my audio file had a release tail due to the ringing.

This is completely normal behavior and you'll find this in any EQ or filter plug-in.

Cheers,

Thanks for the response!

Best,

In my case, it was so bad that I thought I had left my mic unmuted in the room and that there was a low resonance being induced by it when
I was listening to play back. I was recording a VO. I had a Brickwall engaged on the channel at 80Hz - but not any more...;-) I changed the slope to be less aggressive and all was well