There’s more to great‑sounding reverb than loading and tweaking your favourite plug‑in.
No matter how good the reverb plug‑ins that you own are, there are times when the best results can only be obtained using additional processing, either before or after the reverb. In this article, I’ll look at a number of techniques. Some can prevent the reverb clashing with other sounds and help it to sit better in the mix, while other options can add an impression of power, or inject interest and movement. For most of what follows, I’ll assume that the reverb plug‑in is hosted in a bus fed by aux sends from the various source tracks in your DAW session.
Since reverbs add sound to a mix, they have the potential to obscure other sounds, and often cause a build up of ‘mud’ in the low and low‑mid frequencies. To counter this, try rolling some low end off the reverb signal with a high‑pass (low‑cut) filter. Assuming you’re using your reverb as a send effect, try putting a 200Hz 12 or 18 dB/octave filter before or after the reverb. This should work pretty well for most sounds, including vocals. Similarly, rolling off the top end can help if the reverb sounds too sharp or ‘glassy’. In a reverb, there’s rarely much of use above 10kHz, so set a 12 or 18 dB/octave low‑pass (high‑cut) filter there and roll it down to taste. Engineers have combined low‑ and high‑pass filters on the reverb for decades — using both at once in this way is sometimes known as the ‘Abbey Road reverb’ trick.
More detailed sculpting is possible with a parametric EQ, but unless you particularly want to change the tonality of the reverb compared with the source there’s usually no need. If you do go down this road, broad‑brush moves (wide‑Q or shelving boosts and cuts) are usually better, though if the reverb unhelpfully accentuates any resonances, esses or fricative sounds you can try countering that with narrow cuts. That said, there are often better tactics than EQ for that, as I’ll explain later.
Some reverb plug‑ins include high‑ and low‑pass filters, so you won’t always need to use dedicated EQ plug‑ins. Also note that other common reverb controls allow you to damp the highs or change the relative decay times of high and low frequencies; using these can sometimes sound better than filtering everything.
A separate EQ does come in handy, though, where several tracks share the same reverb but you see a benefit in EQ’ing the reverb differently for each source. To do that, create a separate bus for each source you’re sending to the reverb and put an EQ on each bus. Then route these busses to your reverb track. This way, you can have a master reverb EQ on the reverb track, and an independent one for each source on its own bus. Reaper users can also EQ a send without this intermediate bus stage, as described in Martin...