Wulf's Webden

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Cheap Deverb

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Reverb is added to audio signals to create a sense of depth and space. People can spend good money on effects to provide this processing. If you record in a large room with reflective surfaces, you get it for free but with the significant caveat that you can’t turn a simple knob if there is too much reverb and it is interfering with the clarity of the signal.

Actually, that ‘101’ view isn’t strictly accurate. There are audio plugins, grouped under the generic heading of ‘deverbs’, which can do that but I haven’t found a free one yet. I need to do something though because, for the service recordings I’m doing in church, I’ve either got the option of capturing the room (way too much reverb) or recording the mic signal from the desk (which mutes congregational responses and has an annoying background interference that I haven’t managed to eliminate yet).

The cheapest I can find so far is £80 and it doesn’t have a free demo to let me assess whether it is worth it. However, for once the YouTube algorithm came through and, after a lot of fruitless searching on Tuesday, Wednesday brought me a video from Simon Larkin (below) which, in turn, was inspired by a post from riddlermike.

Simon’s Deverb Video

I’ve experimented and found a slightly different workflow on Logic Pro. Rather than duplicating the track, I send it through an Aux bus. If you send 100% of the signal and then, with a gain plugin, reverse the polarity of both channels, you hear nothing. However, if you then add a compressor on the bus (adjusting the audio signal) you can tweak what makes it through – use a fast attack (nothing lost at the start), a low threshold (most of the signal makes it through) and a release time that doesn’t make the result sound too clipped. I also discovered that sending a signal fractionally higher or lower than the main channel preserved a little bit of the background noise, making the effect less obvious.

It is a kind of noise gate but feels easier to control. It does a good job on attenuating the reverb tails, which helps with speech clarity although it can’t do anything about the early reflections which are audible partway through a word. I think it does improve matters though and I will seek feedback after this Sunday’s service to see if it will do or if I need to continue my search and perhaps even splash some cash on solutions.