In an algorithmic reverb, the specific timing and pattern of all the various reflections that build up into the reverberant sound field is controlled by a mathematical formula-an algorithm-which determines the particular character of the reverb in a preset that’s based on that algorithm. ChromaVerbĪs Logic’s flagship algorithmic reverb, ChromaVerb provides a comprehensive set of controls, as well as a good collection of presets that emulate both natural spaces and offer more creative reverb effects. Convolution reverbs provide highly realistic spaces, but since many of the aspects of the sound of a particular space are fixed in the IR recording, there’s typically less user control over the particulars-the key is to have a large library of IRs available, though some convolution reverbs do offer a useful degree of tweakability nonetheless.īoth algorithmic and convolution reverbs are capable of providing rich reverb sounds, so let’s take a look at Logic’s top-of-the-line offerings for each type, staring with the algorithmic ChromaVerb. This has the effect of making the audio sound like it’s in the original space. Just as with instrument samplers, the reverb sample is loaded into RAM, and when signal is sent through the reverb individual digital samples of the audio are multiplied sample-by-sample with the individual samples in the IR-a process called Convolution. This recording is called an Impulse Response, or IR, and it’s the source of the reverb for a particular reverb preset. A full-range impulse (or a swept tone) is played into a real space, and mics pick up the room’s response-the character of the ambience/reverberation in that room. Since the reverb is built up from scratch, the user can usually exert comprehensive control over the various components of the reverb, from the delay time of the initial reflection, to the pattern and density of the Early Reflections, to the decay time-the Reverb Time, aka RT60-of the later reflections.įilters are typically employed to further shape the tonal character of the reverb, and all these adjustable parameters can be saved into various presets, which can either emulate the sound of real rooms and halls and mimic the unique quality of older mechanical reverb devices like plates and springs, or be tweaked for less-natural special effects like reverb pads and swirling soundscapes.Ĭonvolution reverbs, on the other hand, use samples-recordings-of the response of real rooms and spaces as the basis for their reverb sounds.
They’re fairly CPU-intensive, but today’s computers can handle the requirements easily, allowing for multiple reverbs to be used on different instruments and voices in a mix.
Algorithmic reverbs create a reverberant sound field from scratch, by building up many digital delays into patterns characteristic of different types of natural reverberation.