Everything you Need to Know about Reverb

Reverb is by far one of the most useful and interesting effects in modern production. From a mixing point of view it can be necessary to place dry recordings in an imagined space, from drum mics, lead vocals, guitars, percussion etc. From a sound design and production angle you can radically change the tonal makeup of a sound.

I am always excited when getting a new bundle of plug-ins to check the reverbs out, from the run-of-the-mill rooms, halls and standard simulations to the more ethereal, drone-tastic ones.

In this article I want to have a quick look at some of the different types of reverb available, some of my favourites and some reverb party tricks.

Natural Reverb

Reverb is both something we add out of choice but also a natural phenomena we might actually seek to eradicate from our recordings. Believe it or not, not every room actually sounds as nice as a cathedral some sort of utopian glazier.

My home studio for example has certain frequencies that build up due to the nature of the materials the walls, floor and ceiling are made from, their distance and position from each other and probably a whole other plethora of things.

*The Hagia Sophia, Istanbul. Image © Europeish.*

Broadly speaking, this is undesirable, and most recording environments I’ve been in have sought to damped any natural reflections in the build and acoustic treatment of the room and micing techniques.

The Audio Examples

For the purpose of this article I’m going to use the same four audio examples for each type of reverb. Here they are dry with no other effects.

Clean guitar (courtesy of the very talented Martin Case)

D16 Group Drumazon (909 simulator)

Analog bass (Teisco 60f)

Fender Rhodes Mk II

Plate Reverb

One of the sexiest sounding reverb is that of a plate reverb. Plate reverbs are large metal sheets with a membrane at one end and a contact mic at the other. A signal is fed into the membrane which rattles the metal sheet and the contact mic feeds the resulting tones back into the desk.

I remember working at The Strongroom and there being several EMT 140 plate reverbs in the biscuit cupboard (of all places!) – these were hooked up to various desks across the building and at any one time you could send out to them and return the signal in Pro Tools ready to use. Of course the signal would have to be printed (as with any outboard).

Realistically, most of us will never own a real pate reverb, but the lads at Waves (amongst many others) have decent emulations of them. ~~The below video is by Waves, exploring the plate reverbs at Abbey Road Studios.~~

*EDIT* Oddly the video has been taken down. Boo hoo. Here’s a replacement video by LBA Studios:

Plate reverbs sounds fantastic on vocals and drums, clean guitar, horn sections, most anything. Of course my experience with plates has only ever been simulations but their sound quality is pretty decent.

For the below audio examples I’ve used another Waves plug-in, the Renaissance Reverb, using various presets from the Plate folder.

Clean guitar

909

Analog bass

Rhodes

Spring Reverb

By far my favourite analog reverb source is spring reverb. Anyone who’s ever opened a guitar amp might have come across spring reverb when they put it down too hard or have tripped over it. You get this thundering clatter caused by the springs vibrating.

Like the plate reverb, a signal is fed into one end of a spring/some springs and then passed back out the other. It’s duller sonically than the plate, which has more of a shimmering, bright quality.

For the spring reverb examples I used my Doepfer A-199, which meant a bit of a setup to get it working. Inside Logic I sent out to a bus with a very short delay on it, some EQ and a limited. This went out of output 3 into a Radial ReAmper which ran into a Doepfer A-119.

Clean guitar

909

Analog bass

Rhodes

The signal path for this got a little fiddly. After the A-119 it ran into the spring reverb then into a high-pass filter, ALM S.G.B and into a passive vactoral VCA with a DC offset from MATHS. Finally this ran out of the modular into a valve pre-amp and into Logic where it could be printed.

For a more in-depth look at using external hardware, please read this. Anyway, if you’re still with me, here’s the audio examples run through the spring reverb. All that changes in these examples was how much high-pass filtering was going on.

Algorithmic

This is what probably 99% of us are familiar with – the reverb that comes bundles with DAWs as standard. Logic comes bundled with the Silver Verb, Platinum Verb and users from before Logic X might remember the Gold Verb. Live has the imaginatively named Reverb plug-in and other DAWs will have their bread and butter ‘verbs too.

Algorithmic reverb works much in the same way delays units work – using lots of little delays to simulate the sound of a room. Since the 1980s, close micing has become more widely used than ambient micing, and close micing while it retains more of the original signal captures less of the room. This move towards close micing has meant reverb was being more widely used to fake ambience.

Reverb units like the Lexicon PCM-60 allowed simulation of rooms, halls, cathedrals and even the plates and spring type reverbs analog units could produce. The flexibility of this type of reverb is obvious, as there are controls for the balance of frequencies, amount of early reflections, pre-delay, diffusion and many other parameters allowing you to carefully sculpt the ambience you want.

*A Lexicon 480L on an SSL desk, a classic ’80s combo.*

For my audio examples I’ve opted for a free plug-in from the guys at TAL software, the Reverb III. Whilst this is a plate emulation plug-in, it allows us a great deal of control of various aspects of the reflections, aside from a standard dry/wet balance we have a low and hight cut filter, room size, stereo width and a pre-delay control too.

Clean guitar

909

Analog bass

Rhodes

Parameters Commonly Found on Reverbs

Regardless of which plug-in you’re using, there are a few commonalties that will be of most reverbs. I’m going to look at Logic’s PlatinumVerb to explore these. This isn’t a nice exciting reverb by anyone’s definition, it’s more of work horse, but you need some of those to hand when mixing as they’re less CPU intensive and can perform simple tasks while remaining flexible.

Whilst the below example if fairly standardised, not every plug-in will share exactly the same terminology, or some features may be added or omitted. Always check the manual.

I’ve highlighted various features in different colours. Let’s start off on the top left with the orange panel – Early Reflections. This is the term for the initial reflection of a sound in a space. Most spatial plug-ins differentiate this from the rest of the body of the reverb.

Here we can set a predelay (duration of time before the early reflection), the shape of the room it’s based in (having an effect on its tone) and the stereo image of it. Logic’s manual explains:

The optimum Predelay setting depends on the type of input signal—or more precisely, the envelope of the input signal. Percussive signals generally require shorter predelays than signals where the attack fades in gradually. A good working method is to use the longest possible Predelay value before you start to hear undesirable side effects, such as an audible echo. When you reach this point, reduce the Predelay setting slightly.

Just to the right in yellow we have the Room Size, where we can set the distance the opposing walls are from our signal. Underneath we have (in blue) the Reverb section. This is the body, or tail or the reverb.

Similarly to the Early Reflections panel we have sliders for Initial Delay and [stereo] Spread. We can also determine a Crossover frequency, this is where the signal is split for individual processing. Anything above the frequency is processed as high, and below is bottom-end.

This leads us nicely to white panel, which allows a basic EQ circuit. These parameters should be fairly self explanatory. Next to this in pink is controls for our reverb’s tail. Density controls the space between the reflections. Find the sweet spot depending on what you’re inputing.

Next is Diffusion. Algorithmic reverbs works similarly to delays in that they create lots of tiny echoes. It’s probably desirable to reduce Diffusion for percussive sounds and increase it for things like vocals. This parameter also affects the stereo controls elsewhere on the plug-in.

Lastly we have Reverb Time. This might seem strange since we’ve set the Room Size already, but this allows controls of the high-band’s reflections. It’s a bit of a balancing act finding an optimum point between the Room Size and Reverb Time but it’s ultimately more flexible to have both controls. It allows the premise you could be in a big but unreflective room, or a small but reflective room.

The last two colours I’ve not detailed are pretty simple. In red we can balance between the amount of Early Reflection and Reverb [tail] and the green section is a simple Dry/Wet control. Ensure when using reverbs as a return track that you set the dry values to off!

Some Great Algorithmic Reverbs

There’s a tonne of great reverbs out there, all at different price points. I’ll kick off with the Eventide Blackhole. This is a huge, cavernous ‘verb that doesn’t break the bank, and Eventide have been known to do some discounts from time to time. In a similar vein is Valhalla Shimmer and Reaktor 5’s Space Master – all three are excellent ambient sound design tools.

If you’re after something a little more traditional there’s two free reverbs worthy of note, the aforementioned TAL III and Voxengo’s OldSkoolVerb. Not free but cheap is the Focusrite Scarlett Reverb. All three are good work horses but ultimately nothing special, though that’s not a dig, you need things like these in your arsenal.

For a more classic sound I can highly recommend the Lexicon bundle and Sonnox Oxford Reverb. These are clean and classy sounding studio reverbs excellent for vocals and softer sounds.

Another free reverb with a little more of an experimental edge is the Destroy FX Transverb, which allows “speed” (basically pitch) control of two independent reverbs with a buffer size too. It’s fantastic for bizarre pseudo tape effects. Very psychedelic. Sadly no 64-bit support though. You can hear what a wide range of atonal (and tonal!) bleeps and bloops it’s capable of below:

Convolution

Around Logic version 7, I was introduced to Space Designer and the world of convolution reverb. Convolution reverb models spaces by using audio recordings of them, using either a test tone, clapper or some sort of transient sound to capture the reflections and characteristics, That is then cleverly remodelled in the plug-in to replicate the sound in your DAW.

The below video explains how it and how you can make your own using Altiverb, although the technique is very similar in other programs.

I’m using Logic’s Space Designer for the follow examples, changing the patch each time.

Clean guitar (3.7 seconds, Non Linear)

909 (1.6 seconds, Prince Hall Two)

Analog bass (1.9 seconds, Venue Sizzling)

Rhodes (6.8 seconds, Splendid Verb)

Where to Find Impulse Responses?

If you’re not into the idea of making your own IRs there a great many places that have libraries full of them. Here are some:

You can make your own too, here’s a handy guide by SoundOnSound to making impulse responses in Logic’s Space Designer.

Really though, any audio source can be used as an IR. Ableton Max4Live has an excellent convolution reverb (imaginatively titled Convolution Reverb Pro) that allows a simple drag and drop of audio files into the processor. This means you can add any type of audio and have it generated like it were an IR file.

Here’s an example of some drums (dry first) with a pad added to the reverbs IR Drop. It sounds somewhere between a sampler and a gated reverb. I’ve left the tail on so you can hear how the pad sounds in isolation.

Dry

Reverb

Gated Reverb

One final trick I want to leave you with, it’s using gated reverb. This sound has a slightly bad reputation as we associate it with cheap 80s power ballad and MOR production, but it’s actually a neat trick when used subtly or creatively.

There are many patches and presets that claim to emulate gated reverb sounds, but I find doing it yourself allows for far more flexibility and control over the sound.

I’m going to use Logic, but any DAW will do. I’ve added two blank audio tracks, one with a kick and one with a snare.

I’ve send both hits to a return and added the Sonnox Oxford Reverb, ensuring the Wet is set to 100% and the Reverb Time is fairly lengthy.

Now we need to add a gate, most any will do but Logic’s built-in one will suffice. Gates work by discarding any signal below the threshold. A high threshold means not a lot will pass, a low threshold means a lot of signal can get through. However we want to sidechain our gate to our drums. This uses an external trigger to open and close the gate.

Normally if we were dealing with just a kick or just a snare, we could click on the sidechain drop down and select the relevant track but as this is two tracks we need to sum them. Send both the kick and snare to a new return (pre-fader preferably) and disable the output. Now the gate can listen to this return, as it comprises of the kick and snare.

Adjust the gate’s threshold and hold settings to taste. Leave the attack and release quite short. I’m going to add some compression after the gate to beef up the gated reverb even more, Logic’s standard one will do. If you want to push the sound further add in an EQ to shelve out any bottom end and a BitCrusher to dirty up the sound a bit (I’ve used a Resolution of 12 bit and Downsample of x2 to emulate older reverb units).

That’s it! Understanding routing in your DAWs allows you to push this sound even further. You could split frequency bands, add sidechain compression, add tempo-synced pre-delay or even sample length delays to widen it. Hope this has inspired you to dig around your reverb plug-ins a bit more. Enjoy!