User Guide

Module: Master effects
155
can define delay times separately for the left and
right channels. And you can create ping-pong effects
by dialing values with a fixed relation to one another
(say a ratio of 2:1) for the right and left delay times.
The signal then bounces back and forth between the
two stereo channels.
Reverb (hall)
Upon reading or hearing the term "reverb", most
(electronic instrument playing) musicians picture
the knobs and switches on effect devices or amps
bearing that label. Many are unaware of the physics
of reverb, though a deeper understanding of the
phenomenon would certainly be beneficial in
handling reverb parameters when creating electronic
music.
As sound spreads in a room, it is reflected off many
surfaces (walls, ceiling, etc.). Though there is one (!)
direct path to the ear of the listener from every
sound source, it is not the only path that sound can
take. We know that the shortest distance between
two points is the direct route and, by extension, that
any detour like a reflection takes longer.
Consequently, sound waves arrive at the ear of the
listener with various delays.
But delay is not the only side effect of reflected
sound. The energy of sound waves dissipates slightly
with every reflection that bounces off a surface
because every reflecting material also has an
absorbing effect that dampens the signal. In
addition, this attenuation is contingent upon
frequency because high frequencies are soaked up
more readily than low frequencies (see the HF damp
parameter).
So, the things that please (or displease) our ears
consist of the direct signal and all reflected sound
waves. We call the sum of the delayed and dampened
signals "reverb". In the real world, the shape, size
and physical properties of the room in which sound
waves spread determine reverb. In Neuron, we do
this via the type parameter.
A measurable quality of reverb is decay time. This is
the time it takes the sound pressure level to drop 60
dB from the original level (decay parameter).
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