Lexicon PCM92 User Manual

Page 36

Random Delays are similar to Simple Delays, but are especially useful for:

• Multitap Tape Loops

Feedback can be used to recirculate delays. Appropriate use of highpass
and lowpass filters emulates the bandpass effects of multi-generational tape
loops (hiss not included). Feedback diffusion allows emulation of azimuth
misalignment – a hallmark of the sound.

• Early Reflection Modeling

Although different in scope from Lexicon

Ambience algorithms, Random

Delays can be used to place early reflections in stereo or surround fields.

• Modulated Delays

Delay times may be modulated by signal level, LFO or random values.

hALL (SteReo ANd MoNo)

A hall is the principal venue for classical ensembles, but has proven to be
useful for all types of music. A hall is comparatively large, with wall-to-wall
distances that are typically several tens of meters. Smaller halls may be used
for smaller ensembles. The characteristic sound of a hall includes very low
initial reflection density, with little reflection energy before 60-100 mil-
liseconds. Density buildup is more gradual, because of the larger distances
between reflecting surfaces. Reverberation time is somewhat longer as well.
Finally, in most halls lower frequencies reverberate longer than higher fre-
quencies.

This new hall algorithm shares these basic characteristics with Random Hall
and Concert Hall, but is smoother with a more even decay. Its initial density
is also lower than Random Hall so it may be a better choice when the rever-
beration needs to be unobtrusive.