The Context is a digital reverb inspired by 1980's rack mount reverbs, specifically The MidiVerb II, QuadraVerb, and PCM 70. Those early reverb machines tried to emulate real acoustic spaces using limited processing power, which created new sounds that behave like natural spaces. The algorithms were named to evoke the type of space they are trying to emulate, like small rooms or concert halls.
Recording studios and concert halls each have their own acoustic signatures. That was a constraint through the first half of the 20th century, but also helped create a sonic identity for labels like Stax Records. In the 1950s and 1960s, studios built echo chambers to add controlled reverb to recordings. EMT released the first plate reverb in 1957, which used a thin piece of sheet metal to create a room-like reverb sound that took up much less space than an echo chamber. EMT introduced a digital reverb in 1976.
Hammond Organs introduced spring reverb in the 1930s to make home organs sound like they were in a larger space like a church or theater. By the 1960s, spring reverb units were small enough to fit in guitar amplifiers.
Now, we can record the acoustic signature of any space and use convolution reverb to filter our sound through that space's impulse response for an accurate-sounding - but often static - reverb. Algorithmic reverbs like the Context use a network of modulated delay lines and filters with feedback to create a less natural, but more dynamic and tweakable reverb sound. We can fine-tune the response to help an instrument fit into the mix, or create deep pitch-modulated ambience that would be impossible in a physical space.
Terminology:
- Early reflections - the initial filtered repeats that simulate the sound bouncing off side and rear walls the first time.
- Buildup - how quickly the reverb signal reaches full strengths. Some algorithms are explosive, others slowly bloom.
- Density - how complicated the reverb is (after early reflections).
- Diffusion - "smearing" of sound inside the reverb tank, so that you get ambience instead of distinct echos.
The examples given below are common usage and good starting points, not strict rules.
Room
Room reverb has a fast buildup with strong early reflections. With a short decay, it adds some "air" around your instrument to help fill out the sound, but keep it front and center. Works well on vocals, piano, drums, and lead guitar.
Hall
Hall reverb has delayed early reflections and the reverb builds up slowly, to emulate a larger space. The slow buildup can cause lead instruments to lose definition. Great for thickening up strings and pads, as well as modulated ambient soundscapes.
Cathedral
Designed to emulate large spaces with hard walls and more complex acoustics, cathedral reverb has brighter and more prominent early reflections than hall. It builds up faster, for a more immediate sound with some movement in the decay. Works well on vocals, synthesizers, and guitar.
Plate
Plate reverb has a dense sound, with a fast buildup and lots of diffusion. Plates sound smoother than spring reverb, with a warm, open sound, slightly metallic sound that has room-like qualities. Works well on vocals, snare drums, percussion, and tapping or percussive guitar.
Modulation adds rich stereo chorusing. For more "bend", increase the modulation rate to approximately 1:30.
Spring
Spring reverb does not sound like any real space, but adds depth to instruments. Springs have a metallic, clangerous sound that is more of an ambient effect than an emulation of a physical space. Works well on guitar, synthesizer, and dub-style snare drums.
Grain
Without modulation, Context's grain reverb sounds like the Ursa Major SST-282 Space Station, an early digital reverb that used modulated delay lines. With moderate modulation, it creates eerie, haunted sounds. Increase the modulation amount and rate, and the signal is pulled apart into grains of sound that are shifted and fed back. The grain algorithm creates completely unnatural, synthetic ambience that can stretch from complex chorus sounds to dark, modulated synthetic ambience on the edge of breaking up.
Gated
Gated reverb has an abrupt, non-linear decay that creates an unnatural tail. Known for big drum sounds, gated reverb also works well on guitar because you can add more reverb while keeping transparency and space between notes.
Reverse
Reflections get louder and brighter as time passes, giving the impression that the signal is played backwards or coming towards you. Typically used with 100% wet signal, turn the high response down to maximize the effect. Reverse reverb can also be used to create textures. If you mix in some of the dry signal, the reverb will come in as the note attack is fading out.
The modulation knob adds a wash of forward reverb.
Tricks
- Create an (artificial) room sound by using similar reverb sounds across songs on an album to help it sound more cohesive.
- Set the pre-delay and decay time to minimum to add thickness and character without taking up too much space in the mix.
- Set decay time to minimum and using some pre-delay for diffused slapback sounds.