When it comes to defining a truly three-dimensional mix, few tools are more useful than reverb. More than just providing a sense of distance to sounds, though, reverb is also essential for providing a flattering, empathetic environment for your music to exist in. Put simply, music sounds better with a touch of reverb – as anyone who’s sung in the shower will testify! For that reason, ‘acoustic space’ and music have become inextricably linked, from the concert hall’s natural pairing with a full-size symphony orchestra through to the arena-size reverbs used by the likes of Coldplay and U2 to create an epic, stadium rock sound.
From the earliest days of recording, engineers have sought to exploit the musical potential of reverb, even if that necessitated using relatively primitive electromechanical tools such as spring reverb, echo chambers or plate reverbs to achieve a suitable ambience. Nowadays, of course, we have access to a huge range of virtual devices, including convolution reverb, algorithmic reverb and modelled versions of plate and spring devices, enabling us to custom-design an acoustic space that engineers in the 50s would have died for. Yet, for some, reverb is also a willfully neglected area, with many users dialling in a preset and simply setting an arbitrary wet-and-dry ratio.
Arguably the most effective use of reverb usually comes from the combined and contrasting use of three or four key reverbs to provide an acoustic space that your mix sits in. The key to success, of course, is distinction. If each layer of reverb provides something unique – whether it’s the size of the reverb, the timbre, texture or even its stereo dimension – the mix will gain a more diverse and engaging soundstage. It’s also important to recognise that the various instruments in your mix might not fit a ‘one-size-fits-all’ approach. For example, a big, expansive reverb applied to real strings will sound great, but the same sound won’t translate with the same effectiveness on a busy rhythm section.
To explore how reverb can be used, therefore, we’re going to look at three broad types of reverb and explore how they relate to instruments in the mix. We’ll start with super-tight short reverbs, seeing how reverb can be used to add a discrete sense of space to our music without cluttering the overall mix. We’ll also look at the ‘middle ground’, where reverb becomes a more noticeable effect, and how finer details like the colour and type of reverb become so essential to the success of the results. Finally, we’ll also explore some long cathedral-like reverbs and see how the extremities of the effect can become a creative springboard for new sonic exploration.
Small Is Beautiful
Since the ambience-soaked mixes of the 80s, there’s little doubt that the use of reverb has erred towards more cautious and subtle application. However, what might initially appear as being a relatively dry mix can actually contain its fair share of reverb. The important point to note here is the use of short, discrete reverbs – whether it’s using a reverb time no longer than second or more, or so-called ‘small ambience’ settings that favour a short burst of early reflections over a long and pronounced reverb tail.
Short reverbs have a number of distinct uses and musical advantages. First and foremost, short reverbs negate the clutter that longer reverb tails tend to bring. This is immediately noticeable on rhythmic elements (like drums, for example, or rhythm guitar) when you need the reverb tail to fit between the notes rather than smear itself across the entirety of the bar. Using a short reverb, therefore, will retain all the punch of the rhythm section, but still provide some sense of acoustic space to sit your instruments in.
Try using a greater proportion of early reflections for shorter reverbs when you want a hint of spatial dimensionality without the obvious sound of reverb
Room For Improvement
Another important quality of shorter reverbs is the extra body that they can deliver – arguably in much the same way as an engineer might bleed in an amount of ‘room mic’ for a similar effect. Again, this is particularly noticeable on drums. A dry sound, for example, will favour short transients, but add in some reverb and the kit will sound louder, with the reverb adding body and sustain to each drum hit. Vocals can also benefit from this form of body-enhancing treatment, without the clutter of a long reverb tail that also tends to push the vocal to the back of the mix.
Finding some suitable ‘small room’ or ‘ambience’ presets is a good starting point when exploring tighter-sounding reverb effects. As with all areas of reverb, the wet/dry ratio is an important part of the process, and in this case you’ll often find that relatively small amounts of reverb deliver just enough ‘room’ without the reverb dominating the mix. It’s also worth experimenting with the relative balance between the early reflections and the reverb tail, arguably favouring the initial flutter of bright early reflections rather than the more diffuse reverb tail.
The Middle Ground
The ‘middle ground’ of reverb covers a wide range of different sounds and styles of reverb, although unlike the small room setting we’ve previously explored, the effect tends to be heard as a distinct reverb tail lasting around 1–2 seconds. When working with longer reverb tails, of course, we need to better understand the different characteristics of reverb and how they best contribute to the overall effect achieved, whether it’s broad qualities like the type of reverb used or more subtle variations, such as damping and diffusion. As any engineer will testify, no two reverbs sound the same, so it’s worth comparing how they contribute to the overall effect.
On a broad level, most modern-day reverbs are divided into three camps: convolution, algorithmic and modelled. Convolution reverbs are produced using impulse response (IR) files, sourced either from real acoustic spaces or, indeed, sampled from existing software or hardware reverb units. On the whole, most engineers tend to use convolution reverb for its lifelike quality; it has an output not entirely dissimilar from an ambient set of room mics. However, convolution reverb can be difficult to sit in the mix, occasionally lacking some of the sparkle and high end of other reverbs, as well as being slightly heavy in the low mids (although, to be fair, this is actually how real reverb sounds).
Algorithmic reverb is designed from ground up in the digital domain, using a complex series of digital delay lines to replicate how sound bounces around an acoustic space. Although not entirely lifelike, algorithmic reverbs from the likes of Lexicon, TC-Electronic and Bricasti have become ‘go-to’ solutions for many engineers looking for a sumptuous and flattering acoustic to add to a mix. Ultimately, a well-designed algorithm reverb tends to find its place in the mix with relative ease, and given plenty of parameter access, you’ll also find that you can really change and adapt the reverb to suit your needs.
The last category is a growing one: using software modelling to replicate older hardware reverb units, whether it’s the vintage EMT plate used for Universal Audio’s EMT 140 or the spring-reverb emulations found in many virtual guitar amplifiers. Vintage reverb, of course, has a sound all of its own, providing a unique contrast to the digital perfection offered by algorithmic or convolution reverb. Adding a spring reverb to a guitar, for example, or some dense plate reverb across a snare drum will help to give the instrument more definition and distinction in the mix. In particular, the super-dense sound of plate reverb appears to be undergoing a big revival, with bands such as the Fleet Foxes using it to great effect.
Sound And Texture
As you start to explore different reverbs you’ll begin to identify their principal qualities, as well as being able to adjust them to better suit your particular sonic objectives. Given the attention paid to EQ’ing a kick drum or a vocal, it’s just as important to consider how the precise timbre of your reverb contributes to the overall mix, either resorting to parameters within the plug-in or good, old-fashioned EQ to make the ambience sit as required.
Looking at the two extremes, a reverb can be seen as either bright or dark. Bright-sounding reverb will push its way to the front of the mix and make its presence felt. In dance music, a bright reverb will often be used on principal synth lines (often with particularly bright cut-off settings), making both the instrument and the reverb prominent in the mix. But place a bright acoustic guitar through that reverb and the effect will be distinctly less musical. Dark reverb, on the other hand, tends to have a natural, receding quality to it, sitting behind the instrument and not cluttering the high end of the mix in the same way.
Combining contrasting reverb settings will generate true dimensionality in your mix, moving between short, bright reverbs at the front and longer. darker reverbs towards the back of the mix
The timbre of the reverb is largely defined by its so-called damping characteristics, with most reverbs offering some control over the high-frequency and low-frequency damping accordingly. In essence, damping is a progressive attenuation of frequencies, so that despite the reverb starting relatively bright (especially in its early reflections stage) it becomes progressively darker throughout the duration of the reverb tail. In addition to this, a plug-in might also provide some additional filtering and/or EQ to provide the required colour to the reverb tail.
Another parameter worth exploring is the relatively density or diffusion of the reverb tail. In essence, both of these controls relate to the relative density or diffusion of the reverb tail, so that the reverb is heard either as a series of discrete echoes or denser, more homogenous tail of reverb. As a general rule of thumb, smooth, dense reverb tends to suit percussive sounds, while grainer, less diffuse reverb will work better on less percussive instruments (vocals, for example). That said, the relatively dense sound of vintage plate reverb also sounds great on vocals, so it’s worth experimenting to see which works best.
Cathedral Of Sound
Pushing reverb times beyond six seconds or more takes the effect into far more spacious and dramatic territory, arguably making it perfect for sounds that need to sit at the rear of the mix or for deliberate shock treatments (such as large ‘trailer’ hits, when reverb is used as a sound effect in its own right). Arguably, the key point to remember here is moderation in respect to the number of tracks or instruments accessing this super-long reverb. Keep the super-long reverb limited to a few key sounds and the depth and scale will be easy to appreciate. But bury a large part of the mix in this way, though, and you’ll simply end up with an indistinct blur of over-reverberated sound.
Almost in reverse to the discrete use of short reverb, it often pays to be more extreme with the wet return coming from the reverb’s output (in some cases, even using the reverberated return for the ultimate ‘distancing’ effect). In situations where you want to use a large reverb but keep the sound towards the front of the mix, consider increasing the reverb’s pre-delay time to around 70–150ms. Long pre-delay settings will detach the reverb tail from its source, allowing the original source to sound up-front but still have a sense of ambience floating behind it.
As before, consider the sound of the reverb itself. Convolution reverbs have some great IR files sourced from huge cathedrals, but some of the best super-long reverb effects come from algorithmic reverbs such as Lexicon’s PCM Native plug-in (the reverb almost appears to float with infinite sustain). Following the ‘front/middle/back’ concept, this super-long reverb should arguably be the darkest of the three key reverbs (but keep an eye on low-frequency damping so that the output doesn’t become too muddy).
Modelled version of vintage reverbs – like Universal Audio’s EMT 140 are a great way of re-creating the unusual electromechanical reverb effects of the 50’s and 60’s
Given such a Pandora’s Box of reverb options to play with, it’s tempting to use multiple different reverb plug-ins, almost creating a sound specific to each instrument. However, using three or four key reverbs strategically placed across aux faders will ultimately provide more control and flexibility. If the whole mix needs to have a shorter reverb, for example, you need only to adjust four or so plug-ins rather than 24 channels’ worth! However, for principal instruments, particularly vocals, there’s a lot to be said for the extra distinction brought about by the instrument or performer having its own reverb.
Building a refined and coherent ambience to your mixes is one of the most effective ways in which you can transform your music. Beyond the basics we’ve covered here there’s a wealth of other techniques to explore, whether you’re sampling reverb tails to use as pad sounds or adding additional effects to the plug-in’s output to further extend the musicality of the effect. Put simply, reverb in any form is an almost essential ingredient in any form of music, so it’s well worth appreciating the myriad tones and colours it can bring.
Here’s a video from lynda.com that explains a little about Reberb: