Some reverb tips
this came out on Gearslutz a few weeks ago. You might find it useful.
The prominence of the instrument will determine how live the reverb should sound. Why? The reverb is going to reinforce whatever is feeding it. If you have a lead vocal generating a flat reverb, and the drums generating a bouncing reverb, your drums are going to get the attention - which can be good or bad, depending on the scenario. That being said, let's say you want the lead vocals to be the focus. Instead of throwing a compressor on your lead vocals, bus your lead vox to an aux channel, and then compress. Go to the uncompressed vocal channel, and throw an aux send to your reverb channel. This will give you controlled vocals, but live space!
We will be sending other instruments to our reverb channel, but let's focus on getting the reverb right on just our lead. If we can get it right here, everything else falls into place. To do this, we need the reverb loud, the diffusion and decay/density and room size all the way down, the time, and the predelay all the way down. You may have to turn the time up a little so you can actually hear the reverb, but you want to hear it as close to a pulse as possible.
Start with the predelay. This is the first rhythmic element of your reverb. Let's say your bpm is 120. That means you have one half note every 500ms. You have one quarter note every 250 ms. You have one eighth note every 125ms, you have one sixteenth note every 63ms. 32nd notes at 32ms. In order to have the predelay trigger the reverb in a rhythmic fashion, it needs to be at one of these measures. I'd go with 32 or 63ms, because we want the reverb to still feel attached to it's source sound. Also, you notice how I rounded up? That's to put the reverb "behind the beat." This helps create a rhythmic pocket. I might even suggest moving the predelay higher a couple ms, just to make that pocket a bit more solid, and so that the hit of the reverb isn't directly overtop the next part of the music.
Now move on to the Duration. Using the same time rubric, we can determine how long we want our time to be. Texturally, we want our reverb to be clean. This means a long time is going to create a wash sound, and defeat the work that we did on the pre-delay. The reverb time in a small room is very quick. A quarter of a second, give or take. Rhythmically, we want our reverb to pull us into the meter of the song. So we want our length to line up along the same rubric we found for the predelay. Let's say 250ms. This way, we're moving right along to the quarter note pulses. BUT! Consider that our predelay is set to, say, 34ms. This means we have the tail of the reverb pulling us to the beginning of the next reverb, not the beginning of the next pulse. Subtract your predelay from your time, 250-34ms. Set your reverb time to 216ms. Remember, even if you don't hear the difference between 216 and 230, if the track is going to get heavily compressed, that difference WILL stand out.
-Side note- predelay and time are subject to taste. Use the math to get where you want. I usually find the math gets me right there. But make adjustments and go with what sounds best.
Size. Size will effect the tightness of the sound. This is more creative, but here's a good starting place: Divide your time by ten, and round to the closest integer. That's a good number of ft for your room size. Adjust up or down according to tone and texture. Too large will get a spacey characterless sound. Too tight will sound almost more like a echo/delay.
Decay/Density. This is somewhat ambigous, and different processors will give you different results. Basically, I equate this to presence. Remember you have your reverb up loud now, so adjust the presence to match with the instrument that's feeding it. You probably want your reverb a nudge less present than that.
Diffusion. This basically refers to how far the source sound is to your ear. Unless you plan on sending each element to its own reverb (using the same processor with the same settings and using different diffusions is not a bad idea if you have the time) set the diffusion as the average distance between the furthest element in the mix and the closest. If you picture your sound stage as having the drums at the other end of the room as the audience, and the vocalist being halfway toward the audience, you want your diffusion to be 75%. There will be other ques from the mixing of the instruments themselves to put them in their own space.
Damping. Picture the material you want your room to have. Is it metal walls? Is it oak wood? Picture your ideal room and how it sounds, then adjust the damping to meet that. Damping is how long frequencies persist during the period the reverb is presence. Basically fiddle until you get it right. Your going to eq in a moment anyway.
BUT FIRST
Compression? Sometimes, there is a lot of attack sound in reverb. Especially when hot transients from your drums are feeding into it. It might be worth taking a compressor and setting as fast an attack as possible and a really quick release, just to ease off the transients. But be careful. Compression will eat the energy out of your reverb (if there's too much energy afterall, that's the point). Err on the side of caution, and if you're not sure, leave it out. I find I don't usually need to compress out the transients in the reverb. But every now and then, I do.
Ok, now EQ. The idea of the reverb is to lie underneath your sounds. You will find that as other instruments start feeding the reverb, you get fatty build up somewhere in the high mids, somewhere in the mids, and sometimes in the bass/sub bass. Your goal is to find the fattest point in these three sections and use a wide bandwidth to ease this build up away. A HP filter may not be bad to get rid of the bass build up. You can generally cut out anything below 70Hz. Be honest though, that rule doesn't apply 100% of the time - maybe 90% of the time.
FINALLY, start lowering the sends on each instrument individually. Solo one instrument at a time. Lower the send volume until the reverb exists, but the total clarity of the instrument is still present. After this is done for all instruments, start adjusting the send levels by little bits based on what sounds best: Here's a tip: Normally we like to put heavy reverb on things like strings and pads. While that seems logical, it's actually not the way to go. Think about this, if you have a constant tone playing at one level, even if it's way down in the mix, won't it stand out? Take instruments that naturally sustain at one level, or have lots of compression on them, and reduce the amount of reverb. The more dynamic instruments like vocals, should have the most reverb. That means drop the reverb in your heavily compressed drums, and your sustaining pads - not boost the reverb on your vocals. Less is more.
NOW, the final test.
Mute your audio. Mute your reverb aux channel. Wait a minute, shake your head out. Stand up, get a drink of water. Come back and unmute your audio.This is the dry sound, no reverb. Listen for a moment, then unmute the reverb. Does it sound like the song just came to life!?
If it does - your done. If it doesn't, it's back to the drawing board.
