Pumping Reverb

This next little trick is so fresh, it's still hot from the oven. I've only just started using this one on some very recent tunes.

So, you've got a nice little synth stab, a clean guitar riff or maybe just a little plink sound like the one just here:

Bland, boring and doesn't have any character whatsoever. The first thing you then think of is "Hey, I'll put some reverb on it just like I learnt last week. It will then have it's own space and maybe even a bit more character." Let's see how that sounds...

Yeah not bad. It certainly sounds a lot better but it is still not quite enough, is it?. The technique that I've been using to make it more interesting involves setting the original sound to trigger the pumping of the reverb using a sidechain compressor. Sound complicated? It's not really. Have a look at this picture.

You can see that from the input sound (ie. your synth stab, guitar etc.), the unchanged signal goes directly to the master output. However, this sound is also routed to a reverb that is set to 100% wet. Before we sum this with the unchanged signal, however, it is run through the compressor which, with the sidechain, lowers the signal each time the stab hits or the guitar is strummed. Think of it as the reverb only being heard when the original signal is not.

This is what it sounds like:

See how the reverb has now got it's own rhythm? And in the context of the song, it sounds like this:

Much more interesting than the bland plinking sound we had originally. Can you hear the reverb pump?

The easiest way to set this signal path up is to use your returns (sends) with the reverb and compressor sitting on one return. In Ableton Live, however, you can utilise the racks by having one chain for the dry signal and one chain for the reverb and compressor. You may even want to save this rack for use in future projects.

In this song I have even used a similar technique on the bassline but instead of the sidechain compressor, I used the sidechain fakey to keep a constant pump. Can you hear it here?

For those of you who were paying attention you may have noticed that I have an EQ in front of the reverb in the chain above. Now you don't have to EQ the reverb chain every time (and you could even use the EQ in the reverb itself) but it can be useful to throw a high pass filter on it. This cuts out the low end of the reverb and gives the reverb more of an air-like wooshing sound.

Things to try at home

- Adjust the levels of the dry signal and the compressed reverb signal to taste. Sometimes less reverb is more.

- Adjust the EQ of the reverb signal. Sometimes you want that rumble in your reverb

- Try out the compressor settings above but also try different thresholds and attack and release times.

- Why not sidechain fakey if you want a constant rhythmic pump.