Reverb and delay are two audio effects which can be used to give a track as well as your mix more width and depth. In some cases they can simply used as a bit of ear candy to keep your mix fresh and your listener engaged. Let’s talk when to use reverb and delay for different instruments and situations in your mix.
Reverb Vs Delay
First let’s differentiate between the two effects of reverb vs delay. While both effects are used to simulate reflections of sound bouncing off surfaces, there’s one substantial area where they differ: the decay of those reflections.
Delay is a very two-dimensional and, by comparison, a much simpler effect. It simply creates an exact copy of your audio and plays it back at an interval of your choosing.
In most delay plugins like one of my favorites, Echoboy from Soundtoys, the delayed signal can be synced to the tempo of your song.
It can then be played after intervals like an eighth, quarter, half, or whole note after the initial signal, making that delayed signal sound tight in the context of the mix.
I did a complete overview on the types of delay which covers time, basic notes, dotted, and triplet delays as well as specific types like slapback delay, so refer to that for more information.
Delay is much cleaner than reverb because it doesn’t simulate the size of the room via a longer or shorter decay of the signal, it’s simply an exact replica. You can add
Reverb is more associated with depth as this effect is used to simulate the decay of a reflection. This relates to how high and low frequencies differ:
Lower frequencies travel more slowly but are more resilient in their ability to reflect off of or pass through obstacles and walls.
This is reflected (no pun intended) in how longer reverb settings sound (darker/low frequency rich) versus shorter/faster settings (brighter/higher frequency rich).
You also generally have a lot more parameters which relate to how you’re coloring the reverberated instance of your audio as is shown in my favorite all around reverb, FabFilter’s Pro-R 2:
While delays typically just have a high and low pass filter, reverb’s like Pro-R 2 feature parameters outside of the decay time itself for affecting the width, depth, and overall character or tone of the reverberating signal.
When to Use Reverb and Delay
With that context, let’s get back to the subject of when to use reverb and delay in your mix.
While there are no hard and fast rules here above trust what sounds good (while keeping reference tracks at hand for context on what sounds good), delay is typically safer to use without worry of muddying up your mix.
That said, reverb has a lot of applications as its more effective for allowing you to take advantage of the third dimension of your mix. This is important both for creating a more interesting mix but also ironically a cleaner mix as this spaces tracks farther apart from one another with some tracks being up front and others being pushed farther back in the mix.
Enough vague overviews; let’s get into the specific instances of when to use reverb and delay.
When to Use Delay
First, let’s cover the most common and arguably effective applications of delay in your mix:
Vocals
Whether it’s a short slapback for a touch of width or a longer delay to improvise a little depth via some feedback and filtering, delay is great on vocals for giving that vocal more presence in the mix.
Specifically I like to create two Aux/Return tracks and drop a delay on each with slightly different settings to achieve that effect:
I went into how to use delay on vocals in more detail, so refer to that for more information.
You can also have a much longer delay for some vocal throws as a kind of call and response effect or simply to fill up an otherwise empty moment immediately following a certain vocal.
The benefit of a delay on vocals is that, like always, it’s a clean way to fill out the stereo field and place a greater emphasis on what is arguably the most important element in your mix, the vocal.
Snare
Snare delay is a great way to add some natural sounding size to your snare by way of a clean reflection:
As you can see from the recommended settings above (32 milliseconds with a high cut filter), the Haas effect is in play here.
This states that any delay under 40ms will be perceived as the same sound (with no separation detected). This can be applied to your snare or any track in your mix to create some natural sustain.
Turn that delay up slightly to achieve more of a slapback delay effect so you get a very short reflection on the snare to cheat a touch of (clean) depth into that snare sound as you’re giving the effect of a live room with that reflection.
Guitar
Delay works beautifully on lead guitar in particular, so much so that I did an entire overview on the best delay settings for lead guitar.
This included devoting time to one of the most recognizable guitar delays: the dotted eighth.
Whether you know the name or not, you’d recognize the effect.
The dotted eighth effect is on a lot of The Edge from U2’s famous guitar riffs from the 80’s in particular and on The Temper Trap’s biggest single, “Sweet Disposition”:
A little slapback delay sounds good on rhythm guitar when blended in conservatively to give it a little more size in the mix, as well.
Width
I could go on and on about specific instruments delay works well on, but as a general rule whenever you want some more clean size, sustain, or width to a track, try some delay.
Keep that 40ms cutoff in mind whether you just want some more sustain on the tail end of your audio or if you want that separation to create more of a sense of space.
When to Use Reverb
Because of the prominence of low end build up in reverbs by virtue of the aforementioned difference between high and low frequencies, it’s a good idea to apply high and low pass filters to your reverb.
Many reverbs like the FabFilter Pro-R 2 or even my stock Ableton Live reverbs feature onboard filters so that you can decide what frequency range of the reverb itself comes through.
Oftentimes called the Abbey Road Reverb Trick by virtue of its origins, filtering everything below 600Hz and above 6000Hz is a good way to keep that reverb tamed and clean, particularly on the low end.
Even if there aren’t onboard filters on your reverb plugin or you don’t like the results you’re getting from them, you can accomplish the same effect by placing your reverbs on Aux/Return tracks and following them up with EQ plugins to filter out the low and high ends:
You’ll find that you can get away with including more low end via the filter or even using a low shelf to cut away less of that low end of the reverb in a sparser mix. It’s when you have a lot of tracks fighting for a limited amount of frequency and stereo space that you want to be more aggressive with your reverbs.
Now that we’ve acknowledged the importance of cleaning up your reverb, let’s cover a few things you can and should apply it to in your mix.
Vocals
Likewise with delay, I’ll begin with vocals when talking when to use reverb because there’s a lot of great.
And likewise once again, I like two differet reverbs on my vocals; one shorter, one brighter:
Above is my cheat sheet taken from my complete overview on the best reverb settings for vocals.
Essentially I like two reverbs with the the second having double the decay and pre delay length as the first (with more width, as well).
You can blend in more or less of each as necessary, automating more in or holding back the second, larger reverb for bigger moments in the song when you need that vocal to take up more space in the mix.
Snare
Snare reverb is similar to delay, it just gives it a bit more of a realistic sounding decay.
You obviously don’t want to blunt or dull the sound of your snare as this is a huge driver of the energy of your mix, so keeping this short and bright is generally the way to go.
Here are some snare reverb settings which work well for snare reverb which you can apply to whichever reverb you’re using in your mix:
Specifically an EQ’d reverb of roughly half a second and a short pre delay of 10-20ms works well to represent a small room to give that snare a little more natural sounding sustain.
You can adjust the width and color of that reverb to taste, depending on the settings on your reverb.
Arguably the best TYPE of snare reverb to use is plate because it’s generally cleaner and brighter while still giving you some of that desired depth.
I put together a complete overview of plate reverb, so refer to that for more information.
Gated Reverb
Gated reverb is exactly what it sounds like: reverb which is controlled by a gate.
The gate is triggered by the level of the track you’re applying the reverb to. Essentially when the track stops playing audio, the gate snaps shut to silence the reverb with it.
This keeps the reverb tail tight and your mix cleaner, but most importantly it makes a track sound huge while it’s playing.
Here’s a snapshot, taken from my overview on how to use gated reverb:
Gated reverb particularly works well on the snare. This effect was used a lot on pop and rock records after it was initially and accidentally discovered by members of Genesis in the early 80’s during the recording of their “Abacab” record.
Check out my complete overview on how to use gated reverb on drums for more information.
Mix Bus
Depending on the mix, you can get away with dropping a reverb directly on the mix bus itself.
This works to add a little depth but more importantly a touch of cohesion to the mix because you’re applying this effect to every track in your mix equally, giving the sense that every track was recorded and existing in the same space.
Like I always preach when adding ANY processing to your mix bus itself, meaning the track which EVERY track feeds into, less is more.
The smallest of processing additions to the mix bus will have a huge impact, so be conservative with the Wet/Dry Mix percentage on a mix bus reverb and keep it below 15% at most.
Depth
Like with delay, I could go on and on talking about its various applications across your mix, but the only limit is your imagination.
Don’t forget the importance of its role in creating separation in your mix with contrasting amounts of depth between the various tracks. If you have frequency conflicts which can’t be resolved through complimentary cuts or panning, try sending a track farther back in the mix.
One more word on reverb; consider my overview of the best reverb settings if you’re looking to drop a reverb on an Aux/Return track you can apply across virtually every track in your mix:
LASTLY, while I mentioned delay for width and reverb for depth, don’t discount each’s application to the other.
In other words, we can easily use a brighter and drier reverb for a bit of width almost like a delay.
Conversely we can make use of the low pass filter on our delay to make that more contrasting delayed sound like it’s coming from deeper in the image because we perceive lower frequencies as being farther away.
Both reverb and delay have their places in your mix; use them to manipulate second and third dimensions of your mix and automate them in and out at key moments to keep the mix fresh and your listener engaged at all times.
