Where does reverb come from…
The quality and nature of sound pressure waves we hear is directly related to the physical space where the phenomena occur. The reflection of sound is what gives our brain’s binaural system information about the size of the room where we are, the sound source direction, the distance from the sound and also about the room quality (depending on how much of that sound gets absorbed: empty room, full, reflective surfaces…) Waves reflections are used by our brain to define and place that sound in space.
As we know, what is usually called reverberation is a mix of early reflections and decay time (the time that it takes for a sound to decay 60dB from its original pressure level). Sound waves travel in space, reflecting, diffracting over surfaces and coming back to our ears, “mixing” with the direct sound.
Where does digital reverb come from…
Back in the days of jukebox reproduction (the thirties), recording ambient was not an option: any kind of reverberation on a music track would have sounded really bad when reproduced. Those days, ambient was defined by the distance between the microphone and the sound source. The more the distance, the more “room” onto the recording. Then, in 1947, Pill Putnam “invented” the echo chamber, adding reverb to a very successful pop track (you can find an interesting article by Will Shanks on the Universal Audio website here). The echo chambers have been a standard in music production over time, unique in their design and sound.
In 1957 the German company EMT (Elektromesstecknik) released a milestone in modern effect processing: the plate reverb. It was the EMT 140 Reverberation Unit and has become a standard, shaping the sound of vocals and instruments for many years. Plate reverbs are extremely heavy and large (and expensive), hence they often not suitable for medium sized to small studio. (See this article). The plate reverb signature sound has been modeled by plugins manufacturers, to reproduce its special color and apply it easily onto tracks. For example, the Waves Abbey Road Reverb Plates, reproduces the four EMT 140 housed at Abbey Road Studios, used to complement the sound of the echo chambers.
Not even two decades after, in 1971, Lexicon – a pioneer company in sound processing – introduced to the market the first digital delay, the Delta T-101. A few years later, in 1976, Dr. Barry Blesser, that had already worked with Lexicon, developed for EMT the first digital reverb unit: the EMT 250. The EMT 250 was a complete effect processing unit – with control levers for decay and delay. If you’re interested in an in-depth study on sound behaviour in space, Dr. Barry Blesser has recently written a book called Spaces Speak are you Listening?: Experiencing Aural Architecture
After the Delta T-101, in 1978, Lexicon introduced further digital reverb equipment, beginning with the Model 224. The PCM series, a more compact and affordable effect process unit series, was launched by Lexicon in 1984 (PCM-60) followed by the PCM-70, a multi-effect unit featuring a digital screen interface. Another widely known multi effect unit was the Model 300 – launched in 1997. I used the Lexicon 300 for many years, and it is definitely a great, smooth and safe option both live and in the studio – with its very distintive and full sound.
With digital revolution, that started around 1992, software began to take over analog equipment, and eventually outboard gear was replaced or complemented by state of the art plugins. Effect processing are now controlled inside the box – with CPUs capable of intense workload – saving on costs – and cables 🙂 Also, plugins give us the option to craft a desired sound from an incredibly wide range of factory presets and custom controls.
How to choose and apply the right reverb to your tracks…
What is the point of adding reverb (or any kind of artificial time processing effect) on a track? It may be an obvious question – but it is something I often think of, especially when randomly listen to new artists and bands on Soundcloud and the likes. Ok, all you can do is produce your tracks at home, on your DAW. And that’s fine – there are so many clever productions out there with low budget gear and good sound. But sometimes production clichès like reverb on vocals can ruin an otherwise interesting song. And even if in music production (and art production in general) there shouldn’t be any strict rule, mixing choices should have some “sonic logic“.
Short example. There’s this nice guitar riff – then some well written keys layers and tidy and tight rhythmic section going on for a handful of bars. Then… the first vocal line appears. But, wait, something’s not right. The instruments are well positioned left to right in a room sized space – while the singer seems to be locked in a bathroom, with the mic positioned in the sink hole. If that was the effect the band was trying to reach – well done. But the information processed by my hearing system is: the instruments are playing here, and the singer is somewhere else – somewhere that sounds really bad. This is fake – not natural.
- After choosing a reverb, some kind of ealy reflections + decay that is nice on the vocals, I start with applying the same quality (not level) of reverberation to other instruments in the mix that may benefit from it. Each track should be processed independently.
- Always check the wet/dry mix, and the HP filters – to avoid unwanted LF build up. Then, if the producer or the band wants to be creative with DSP – that can lead to even better results. But I like to start with natural sounding tracks.
- Slower BPM songs may benefit from longer reverb times – especially on vocals. But try to keep it tight (maybe using just delay to add color and body) to faster tempos.
- Close miking should avoid room reflections and reverberation been recorded to track – but that is not always the case – so be aware of that.
- Use your aux and return the effect to a stereo track.
One last thing: at the beginning of this article we shortly described the very nature of reverberation: first we hear the direct sound waves, then all the reflections. The closer we are to the sound source, the more direct sound we will hear – when compared to the level of the reflections. If the direct sound is far away from us in space, the mix of the original sound and reflections will be different (higher reverb level).
So it is clear that adding too much reverb on a track pushes that sound away – in space -from us (and away from the rest of the instruments in the mix). Adjusting the levels helps, but if you want to keep the vocals upfront in the mix – pay special attention to it.
With close miking we acquire dry signals – what we want is almost exclusively direct sound, so that we can better process it with dynamics and fx. Reverb puts the audio tracks back in a physical space – where our ears are used to hear sound, where instruments and voices can breathe, feel natural and alive.