|RT60 or Reverb Time or Decay
|Sets the time required for 60dB
of decay at 1Khz. Can be impacted by size parameter.
|Usually the RT60 time should be
inversely proportional to reverb level. Long RT60 times can work
in a sparse mix but can clutter a busy mix. Best approach
for busy arrangements is short RT60 on individual instruments so that
they each have their unique ambient space that do not conflict each
other in the final mix.
|Delays the input signal to the
reverb processor. Settings of 40ms or less allows the reverb to
blend closely with the direct sound. External analog BBD or tape
delay is sometimes substituted for their warm sonic sound.
General guidelines: Up-tempo
drums/percussion 25-50ms Ballad
drums/percussion 40-80ms Vocals
75-125ms String Section
100-200ms Acoustic instruments
45-90ms Brass 50-100ms
|Enhances clarity of direct sound
or front-to-back imaging. Conveys distance and volume within an
acoustic space. At moderate predelay times > 40ms the
reverbration is placed behind rather than on top of the direct
signal. Can produce punchier less washed out mixes. Long
predelay times can sound unnatural but may have interesting uses.
|RT Contour EQ
|Alters the attenuation or gain
of the signal source at selected frequency centers before it enters the
reverb processor. External EQ can be used. Starting points
can be 50-120hz and 7-12Khz.
|Simulates reflective quality of
absorbent or hard surfaces from warm-sounding old wooden concert halls
to hard metal walled rooms. Can be used to correct unwanted
resonances or to correct dull/edgy/rumbly reverb sounds.
|Rolloff or HF Cutoff
|Uses low pass and/or high pass
filters to roll off high frequencies and/or low frequencies before the
reverb processor. EQs affect only those harmonics
within a bandwidth surrounding the frequency center, while filters
affects all harmonics above (low pass) or below (high pass) a cutoff
frequency at a slope of (x)dB/oct. Typical low pass filters: 3Khz
@ 6dB/oct, 7Khz @ 6dB/oct, 10Khz @ 48dB/oct.
|Mimics the effects of air
absorption due to environmental variances. Prevents large size
reverbs from sounding unnaturally bright. Natural reverbs contain
few harmonics above 10Khz.
|Simulates the slap-like echo(s)
heard before the reverb which are the first reflections of an ambient
space of hard surfaces. Not the same as predelay. Number of
reflections, timing, and level varies depending on reverb class.
Some digital reverbs offer variations of echo times and level.
|Can be used for doubling
(50-80ms) and echo effects combined with the reverb. Can
intensify the initial punch of drums (0-40ms). May interfere with
the feel or tempo of the music. Can simulate the effect of a
procenium arch in a concert hall. Use caution if echo time is
|Controls the extent to which the
initial reflections of a reverbrant space are smoothed out over
time. Higher diffusion emulates rough irregular reflective
surfaces or obstructions in free space which creates a smooth more
mellow more colored sound while low diffusion emulates a
non-obstructive smooth flat reflective surface which creates a clearer
brighter less colored sound. Can be impacted by position, size,
and density parameters.
|Simulates different reflective
properties of materials such as hard flat surfaces (tile, metal, glass)
or surfaces with rough irregular cavities (unfinished wood). High
diffusion works well with signals containing fast transients
(percussion, piano, guitars) while low to moderate diffusion works well
with signals of slower transients (vocals, brass, reeds, strings).
|Controls the time displacement
and number of the discrete closely spaced reflections in an ambient
space. Higher density settings creates richer sounding reverbs
with more even natural reverb tails. As density is lowered the
reverb sound thins out and the reverb tail may "flutter".
|Decreasing density may not be
pleasant on fast transient sources such as percussion.
|Varies the envelope properties
of a reverb. The time it takes for the reverb sound to build-up
and decay 15dB determines the perceived reverb time regardless of RT60
setting. At minimum settings, the reverberation envelope builds
up very quickly to maximum amplitude then decays quickly at a smooth
rate set by RT60. Increasing this parameter slows the build-up
and introduces a sustained stage (see Spread parameter) before the
decay stage. High settings introduces a secondary lower level
sustain portion to simulate the very diffused reflection off the back
wall of a hall. Extreme high settings results in an inverse
sound. Predelay is not an effective substitute as it does not
create the same effect. Can be impacted by size parameter.
|Effective for creating a sense
of depth and space without using long RT60 times. Echograms of
some very good recording halls reveal a rather uneven initial build-up
and decay, giving a much longer effective reverb time than the RT60
setting would suggest.
|Controls the attack time and
length of sustain at increasing settings of the Shape parameter.
Can be impacted by size parameter.
|Combined with Shape parameter,
can provide the sonic impression of room size.
|Simulates the listener's
perspective of any position in an ambient space relative to the sound
source. Impacts arrival time, energy, frequency response, and
diffusion of the early reflections.
|Creates sonic image of any
position in a large ambient space - close to the sound source, the rear
of the ambient space, or anywhere in between.
|Simulates the size of a room
which impacts the sonic character of a reverb class. Diffusion,
RT60, shape, and spread are usually scaled with this parameter.
This parameter refers to the longest dimension of the room and is
usually in units of meters.
|Simulates any room size from a
closet to a living room to a recital hall to a concert hall to the
Houston Astrodome. As size increases, diffusion should be
|Shortens the RT60 times at
|Decreases reverb resonance at
desired frequencies of a signal source.