Size
Often referred to as depth or room size, size indicates the size of the room you’ll be putting your sound in with your reverb effect. The larger the size, the longer your reverb reflections will get.
The Size parameter allows you to control the size of the space the listener will perceive your sound in.
The bigger the size, the longer the reverb will take to occur, and vice versa for smaller size.
Size also affects the stereo image, with larger rooms usually giving a wider stereo image. Thus, the size parameter allows you to scale from longer, more expansive sounding reverb down to shorter, more intimate, and narrow reflections.
Setting your Size parameter in relation to your Decay is the key combo with reverb, so prepare to fiddle with these two steps a bit.
Decay
Also known as reverb time or RT60, Decay refers to the amount of time it takes for the reflections of your signal to run out of energy and stop.
Decay is the most important part of your reverb because it sets the amount of time it takes your reverb to return to silence.
Setting it too long leads to most of the problems associated with reverb and muddy mixes. When the reverb continues for too long, all the many iterations blend together and you can’t tell one sound from another—this is when you’ll know your reverb has gone too far.
As I mentioned before, Decay is traditionally scaled in relation to Size: larger rooms tend to have longer decays, so setting a large size with a long decay or a small size with a short decay is typical.
Most presets will likely do this automatically. But adjusting the two independently can create some really cool effects. So don’t be shy to go against conventional wisdom.
Set your decay time inversely to the amount of wet reverb signal you’ll add to your mix – in other words the wetter the mix, the shorter the decay, the drier the mix, the longer the decay
Reverbs with shorter decays have more freedom to be very loud because they will end quickly and not stick around muddying your mix. Reverbs with longer decays should be kept at a lower volume, otherwise your mix can sound like it’s lost in the Grand Canyon.
Hot Tip: For busy arrangements, use reverbs with shorter decays on individual instruments in order to keep their unique qualities crisp and clear.
Pre-Delay
The distance, or time, between your initial sound source and the first early reflections.
Pre-Delay gives you some space between your dry signal and the wet reverb signal.
A lower pre-delay time will give little or no time between dry signal and your reverb—thus simulating a small room—but can make your reverb messier.
Mid-sized pre-delays will give a slight delay to your reverb, simulating a larger space and keeping the dry signal and reverb clear of each other, removing muddiness.
Early Reflections
Sometimes called initial reflections or pre-echoes, Early Reflections settings determine the level of the very first reverb reflections you’ll hear.
Early reflections tend to sound more like echoes than normal reverb so treat them as such—if you want to create an echo or doubling effect, louder early reflections are excellent for this.
But be careful, echoes can interfere with the rhythm, tempo or groove of a musical piece. Stick to a lower volume to allow for easier blending.
Diffusion
Diffusion, also known as shape, represents the complexity of the room the reverb takes place in.
More complex rooms mean more surfaces to bounce off of and thus more diffusion. Diffusion also controls the density of the amount of reverbs, allowing you to create a more washy effect or have many distinct echoes.
Diffusion allows you to add (or remove) texture from your reverb. In the example above, diffusion levels are represented in the diffusion network section of the reverb.
Higher diffusion levels simulate a more complex space with many obstructions (think of a packed concert venue). It also creates a smoother, warmer, more coloured sound.
Lower diffusion levels simulate a basic shape with unobstructed, flat, reflective surfaces (think of an empty garage).
Lower levels create a clear, bright, less coloured sound. Diffusion can also affect the Decay time of the reverb, so this gives you another option to smooth out your reverb tails.
Hot Tip: Use a high diffusion settings to remove metallic clangs from percussion instruments.
Mix
Mix, also known as wet/dry mix, controls how much of your wet signal (signal with reverb) is mixed into your dry signal (without reverb).
The mix parameter is necessary because reverbs will be patched in as an aux send.
Your mix level (wet/dry) is overall your most important parameter.
It determines how your reverb is going to interact with the other elements of your mix and how much of your effect you’re folding back into your session.
Adjust the wet/dry mix level to add a little more or a little less reverb until it suits your mix perfectly. Always let your mix guide you for how much effected signal.
Hot Tip: Reverb tails are often more noticeable after mastering, so make sure to mix reference your track throughout to check your tails.
Because your reverb is set up as an auxillary send effect, you can have multiple different instruments sending different amount of dry signal to your reverb return.