Creating a reverb algorithm is part art and part science.
The science bit is all about the naturalness of the sound -
whether the simulation convincingly conveys the "feel" of
a real room.
Some digital reverbs don't have the horsepower
to run a sufficiently complex program to achieve "naturalness."
Without enough processing power the effect will suffer from low
echo density or unnatural density growth with time or comb filter
effects, etc. As Einstein is alleged to have said "things should
be as simple as possible, but no simpler." This principle certainly
applies to reverb algorithms.
The art of reverb algorithm design begins with simulating a
'room' that actually sounds good. Needless to say, rooms exist
in the real world that sound awful. The structure of the reverb
algorithm combined with the choices of delay lengths, interconnects,
filter placement, early reflections, etc. all contribute to the
overall sound. The final element of the art of reverb design is
the designer's choice of the ways in which, and the extent to
which, the artist/engineer/producer is permitted to modify the
effect. What are the parameters and what do they do?
The degrees of freedom available to the designer guaranty
that no two (sufficiently complex) reverb algorithms will sound
the same. Each will be unique. There are a number of popular
digital reverberators for good reason. Each has a distinctive sound,
each has a particular set of possibilities. The SP2016 reverbs have
attracted a loyal user base because of a particular blend of art
and science. They sound natural. They sound distinctive. And,
although they allow the user to vary the effect dramatically, the
controls can't be set in such a way as to create an unnatural
sounding effect - this is a good thing.
The algorithms naturally simulate every aspect of the sound of a real
enclosure - from the complex early reflections, to the natural way
in which the echo density increases with time, to the smooth Gaussian
decay of the reverb tail. A powerful simulation that lends itself to
parametric control - a good thing indeed.