DigiTech RP21D Dispersion, Diffusion, Over Type, Over Freq, Prim & Secd Damp, Low Pass, Time

	RP21D User’s Guide	Section Two - Editing Functions
Dispersion	Controls the distance (time) between the echoes set by DENSITY. If DENSITY is set low and DISPERSION is set high,
	the initial room echoes. Dispersion can be heard as discrete echoes followed by smoother room reverberations. Set
	DISPERSION low for a dense cluster of reflections during the early portions of DECAY. Ranges from 1 to 5.
Diffusion	Simulates the presence of different room materials by controlling the smoothness of reverberations through the
	course of DECAY. Low DIFFUSION settings are great for simulating hard, flat surfaces while higher DIFFUSION
	settings can be used to simulate the presence of irregular surfaces in the room such as natural rock masonry or
	man-made diffusers. Unlike flat surfaces, these materials reflect (diffuse) the sound in many directions because of
	the irregularity of the surfaces themselves. This builds smoothness over the reverb progression. Ranges from 0% to
	99%.
X-Over Type	Selects which crossover type will be used for the Primary Secondary reverb stages. The two crossover types are High
	Pass (HP) and Low Pass (LP).
X-Over Freq.	Selects the Frequency where the crossover begins to function. Ranges from 25Hz to 20kHz.

Prim & Secd X-OverThese two Parameters allow the crossover to be turned On or Off for each reverb stage. When Off, that particular stage will be full bandwidth, otherwise its frequency response is limited by the X-Over Type and Frequency Parameters.

Prim & Secd Damp	Adjusts how quickly the room absorbs the high-frequency reverberations. In a real room, absorptive materials can
	be used to dampen the natural high-frequency reverberations of the room. High settings of DAMP cause the rever-
	berations to darken tonally and become less defined over the course of DECAY. Low settings cause less dramatic
	room effects on the tone of the reverberations. Ranges from 1 to 7.
Low Pass	Selects the frequency above which all frequencies are rolled off. This control can be used to darken the response of
	bright-sounding gated reverbs. Ranges from 100 Hz to 8 kHz in the Gated Reverb and from 100 Hz to 20 kHz in the
	Stereo Gated Reverb.
Time	Controls the length of the gated reverb in milliseconds (much like the DECAY control of a normal reverb). Ranges
	from 25 milliseconds to 300 milliseconds in the Gated Reverb and from 500 milliseconds in the Stereo Gated
	Reverb.
Blend	Cross-mixes reverberations from the left side into the right side and vice-versa. This can be used to increase the
	realism of the simulated room by adding reverberations from different parts of the room to each channel. Ranges
	from 0% to 99%.
Prim & Secd Blend	Adjusts the amount of BLEND for the Primary and Secondary reverb stages. See BLEND above for a complete
	parameter description.
Decay	Controls the length (RT60) of the room reverberations. This one control could have been divided among Size and
	Reflection controls but has been simplified here for easier use. To simulate a large room, use longer DECAY settings.
	For small rooms, use shorter DECAY settings. For more natural sounding reverbs, you may also want to decrease the
	DENSITY setting as DECAY is shortened. Ranges from .5 to 23 seconds depending on the Reverb Type currently
	selected.
Prim & Secd Decay	Controls the length (RT60) for the Primary and Secondary reverberation stages. This Parameter interacts with the
	SIZE and REFLCT Parameters. Larger SIZE and REFLCT settings will allow longer reverb decay times while smaller
	settings reduce the length of the reverb decays but produce better small environment emulations. Ranges from .26 to
	11 seconds.

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