Reverb and delay turn a pile of recorded tracks into something that sounds like it happens in a place. They are also the fastest way to ruin a mix. When everything has a wash on it, the vocal loses its edge, the drums blur and the low end gets heavy for no reason. The fix is not to use less effect everywhere. It is to choose the right sound, shape it and clean it.
Short reverb or long reverb
The most important setting is the decay time, the time it takes for the tail to fade. A good rule: the busier and faster the song, the shorter the tail.
- Short (a room or small plate, up to about a second): adds body and glue without pushing sounds far away. It suits fast songs, dense arrangements, drums and rap vocals.
- Long (a hall or large plate, two seconds or more): adds size and emotion. It suits slow ballads, ambient music and sparse arrangements, where there is room for the tail to bloom.
Listen to where the tail ends. If it's still ringing when the next phrase begins, it is covering the next words. Shorten it or tuck it under the vocal in the gaps. If the tail has died long before the next note, you can afford to make it longer.
Pre-delay: keep the voice in front
Pre-delay is the short gap between the dry sound and the start of its reverb. With no pre-delay, the reverb starts immediately, the sound feels pushed back and the words lose definition. With 20 to 80 milliseconds as a starting point, the dry vocal hits first and the space blooms behind it. A longer pre-delay, set to a sixteenth or an eighth note of the tempo, lets you use a big reverb without smearing the lyrics.
To test it, listen to a word that begins with a sharp consonant. If its start is still clear, the setting works.
Send or insert
Use a send for almost everything. You create one reverb on an auxiliary track, set it to 100 percent wet, and send each instrument to it in the amount you want. All the tracks share the same space, so the mix sounds consistent, and you save processing power.
Many mixes need only two or three reverbs: a short room for drums, a plate for the vocal and, for special moments, a long hall.
Use an insert, the reverb placed directly on the channel, only for a deliberate effect, like a reversed reverb on a snare hit or a single sound that should live in its own space.
Delay timing from the tempo
Delay is cleaner than reverb because the repeats are separate and rhythmic. Set the time from the tempo, so the echoes fall on the groove. One quarter note in milliseconds is 60000 divided by the BPM.
- At 100 BPM: a quarter is 600 ms, an eighth is 300 ms, a dotted eighth is 450 ms and a sixteenth is 150 ms.
- At 120 BPM: a quarter is 500 ms, an eighth is 250 ms and a dotted eighth is 375 ms.
Most plug-ins can sync to the tempo for you. Use an eighth for a quick echo, a dotted eighth for a rhythmic bounce and a very short setting, around 80 to 120 ms, for a vintage slapback on a vocal or a guitar.
Keep the feedback low so that the echoes fade after a few repeats. For vocals, a delay that only catches the last word of a phrase often sounds better than a constant echo. Automate the send so it opens only on those words.
Clean the effects
This is the step beginners skip, and it is why mixes turn muddy.
- High-pass the effect returns. Cut the lows from the reverb and delay returns, starting around 200 to 400 Hz. The low end of a reverb adds weight that the bass and kick already provide.
- Low-pass the highs. Rolling off from about 6 to 10 kHz stops the tail from competing with hi-hats and harsh "s" sounds.
- Duck the tail. Put a compressor on the reverb or delay return and trigger it from the vocal. The effect then gets quieter while the singer sings and rises in the gaps.
- Keep the sub dry. No reverb on the kick's low end, on a bass or on an 808.
- Check in mono. Very wide reverbs can thin out when the track is summed to mono.
These numbers are starting points. Adjust them by ear.
What this looks like in different genres
- Pop or ballad vocal: a plate of about one and a half to two seconds, 30 to 60 ms of pre-delay and a soft dotted eighth delay.
- Rap and trap: a close, mostly dry vocal, a short room or small plate and delay throws on the ends of lines. Ad-libs can take more wash.
- House and dance: short reverb on drums, longer on claps and a vocal tail that ducks with the kick or the voice.
- Acoustic and folk: a natural-sounding room or small hall. On plucked instruments such as the tar, a big digital hall tends to smear what the instrument already gives.
- Ambient: long and wide, but with the lows cut and only a few other layers in the way.
Before you finish, mute the returns and check that the mix is still clear, then check it in mono and on a phone speaker.