Lexicon 960L Owner's Manual page 70

Using the Reverb Programs
Parameters Used in the 960L Algorithms (cont.)
RearRvb Rear Reverb Level (Surround algorithms only). Like RvbLvl in Stereo, this controls the level of the rever-
berant tail, but only for the LS and RS outputs. This allows their levels to be set relative to the early
reflection levels and the other reverb tails. RvbLvl is a master control for CtrRvb, FrRvb and RearRvb.
RShape Rear Shape (Ambient Chamber algorithm only) sets the contour of the initial reverberant-energy
growth for the rear channels. Low values produce a very rapid onset, as you'd find in a small cham-
ber. With larger values, the reverberation "blooms" over a few hundred msec, much as it would in
a good, Romantic-era concert hall, and the listener's perceived position moves farther back into
the hall. See also Contour, Rspread, Shape, and Spread.
RSpread Rear Spread (Ambient Chamber algorithm only) works with RShape to control the profile of initial
reverberant-energy growth for the rear channels, stretching or compressing this contour in time to
make reflections closer together or further apart. With complex material, it may be advisable to use
a moderately high value for Shape and a moderately low one for Spread to create a bit of space
around the original signal. See also Contour, RShape, Shape, and Spread.
RtHicut Reverberation Time High Cut. In real rooms, the timbre of the reverberant tail becomes darker over
time due to the air's absorption of high-frequency sound energy. This control models that behavior,
though over a much wider frequency range. When you set the cutoff to very low frequencies, the
duration of the reverb will be much shorter than the value shown by MidRT.
RvbLvl Reverberation Level controls the level of the Reverberant tail, allowing its level to be set relative to
the early reflection levels. It is normally set to Full, but may be reduced for effects where pre-echoes
should dominate. In surround algorithms, this is a master control for CtrRvb, FrRvb and RearRvb.
RvbPreD Reverb PreDelay sets the number of milliseconds between a sound and the onset of the reverbera-
tions it excites, equivalent to the time of first reflection. In the algorithms that include the Shape and
Spread controls; it is better to extend the time period before reverberant decay using Shape and
Spread. In general, we recommend leaving the Reverb PreDelay set at the preset value.
Shape Shape works with Spread to control the profile of initial reverberant-energy growth. Shape sets the
envelope of the energy build-up and Spread stretches or compresses this contour in time. Low val-
ues of Shape produce a very rapid onset, as you would find in a small chamber. With larger values,
the reverberation "blooms" over a few hundred milliseconds, much as it would in a good, Romantic-
era concert hall. Large values of Spread and Shape can create "inverse" effects (see note under
Reverse algorithm).
Shelf Shelf (Random Hall only) controls a shelving low-pass on the reverb output. It modifies the low-pass
characteristic of the rolloff control, turning it into a shelving filter. Both the pre-echoes and the rever-
beration are affected. For example, if Shelf is set to –6 dB, frequencies below approximately Roll /
2 will be boosted by 3.5 dB, while above approximately Roll / 2 response will be flat. For realistic
musical acoustics, Shelf should be set between +12 and –6 dB and Roll should be set between 700
Hz and 1.5 kHz. While this control can occasionally be useful to increase the apparent low fre-
quency content of the returns, it does so at the expense of eliminating the overall rolloff charac-
teristic that typically begins around 2kHz. Thus it is probably best to leave Shelf set to zero. If more
LF is desired in the returns, use console equalization to increase the low frequency content by about
~3dB below 200Hz.
Size Size is a scale factor that alters the length of most of the reverb's delay elements. This control is cal -
ibrated in units that approximate the longest dimension of the reverberant "space" in meters. In
practice, perception of room size is also strongly determined by Shape. Size strongly affects the
overall timbre of the reverberation. Values less than 25 have a noticeable "small room" coloration.
For the most neutral sound with the programs that have Shape and Spread controls, set Size to
about 30M, and the adjust the apparent size with Shape and Spread.
5-14
Home Next Page >>
<< Go Back
Lexicon, Inc.