Single Setup Algorithms; Random Hall - Lexicon M300L Owner's Manual

300L Owner's Manual
Single Setup
Algorithms

Random Hall

General Description
4-2
The 300L incorporates the results of a great deal of research into acoustics and
reverberation. Reverberation, or reflected sound energy, gives recorded music
a sense of being performed in a real acoustic location.
In the 300L, the Size, Spread and Shape controls allow adjustment of the buildup
and decay of the initial part of the reverberation envelope. Shape controls the
shape of the envelope, while Spread and Size set the time over which this shape
is active.
In the Random Hall program, Size acts as a Host control for the apparent size of
the space being created by the 300L. Both Spread and Reverb Time vary
linearly with the setting of Size. Thus maximum reverb time and spread require
high settings of Size. To find an appropriate reverb sound, start with a preset with
a similar sound to what you want to end up with. Simply varying Size is often
sufficient to arrive at the exact sound you are seeking.
Once a size has been selected, Spread and Shape are used to adjust the shape
and duration of the initial reverb envelope, which together provide the major
sonic impression of room size.
When SHAPE is at minimum, the reverberation envelope builds up very quickly
to a maximum amplitude, and then dies away quickly at a smooth rate. This
envelope is characteristic of small reverberation chambers and reverberation
plates. There are few (if any) size cues in this envelope, so it is ineffective in
creating ambience. With this Shape setting, Spread has no effect. The density
is set by the size control, and the rate of decay is set by Reverb Time. This
reverberation envelope is typical of many of the popular digital reverberators of
the last few years.
As Shape is raised to about 1/8 of its range, the initial sharp attack of the
reverberation is reduced, and reverberation builds more slowly. The envelope
then sustains briefly before it begins to die away at the rate set by Reverb Time.
Spread has little or no effect on this shape.
When Shape is at 1/4 of its range, buildup is even slower and the sustain is
longer. Now Spread affects the length of both the buildup and the sustain. As a
rough estimate, the sustain will be approximately the time value indicated by the
Spread display (in milliseconds).
As Shape is raised further, the buildup and sustain remain similar, but now a
secondary sustain appears in the envelope, at a lower level than the first. This
secondary plateau simulates a very diffused reflection off the back wall of a hall,
and is effective in creating a sense of size and space. This reflection becomes
stronger and stronger, reaching an optimal loudness when Shape is at about 1/
2 of its range.
The highest Shape settings are typically used for effects. Near the top of the
scale the back wall reflection becomes stronger than the earlier part of the
envelope, resulting in an inverse sound.
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