Lexicon 960L owner manual RearRoll, RearRvb, RShape, RSpread, RtHicut, RvbLvl, RvbPreD, Shelf

960L Owner’s MaunalUsing The Reverb Program

Parameters Used in the 960L Algorithms, Continued

RearRoll	Rear Rolloff (Surround algorithms only). Like Rolloff in Stereo, this controls the cutoff frequency
	of a 6dB per octave low-pass filter at the output of all processing, but affects the rear (LS and
	RS) channels only. A separate parameter, FrRoll, controls the rolloff for the front (LF, C, and RF)
	channels.
RearRvb	Rear Reverb Level (Surround algorithms only.). Like RvbLvl in Stereo, this controls the level of
	the reverberant 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
	chamber. 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
	reverberations 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 values 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 reverberation 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 frequency content of the returns, it does so at the expense of
	eliminating the overall rolloff characteristic 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 ~3dB below 200Hz.

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