FXAlg #13: Stereo Hall
Algorithm Reference-25
To gain control over the growth of reverberation, the left and right inputs each are passed through an ÒinjectorÓ that
can extend the source before it drives the reverberator. Only when Build Env is set to 0% is the reverberator driven
in pure stereo by the pure dry signal. For settings of Build Env greater than 0%, the reverberator is fed multiple
times. Build Env controls the injector so that the reverberation begins abruptly (0%), builds immediately to a
sustained level (50%), or builds gradually to a maximum (100%). Build Time varies the injection length over a range
of 0 to 500ms. At a Build Time of 0ms, there is no extension of the build time. In this case, the Build Env control
adjusts the density of the reverberation, with maximum density at a setting of 50%. In addition to the two build
controls, there is an overall Pre Dly control that can delay the entire reverberation process by up to 500ms.
Parameters:
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Wet/Dry
The amount of the stereo reverberator (wet) signal relative to the original input (dry)
signal to be output. The dry signal is not affected by the Bass Gain control. The wet
signal is affected by the Bass Gain control and by all the other reverberator controls. The
balance between wet and dry signals is an extremely important factor in achieving a
good mix. Emphasizing the wet signal gives the effect of more reverberation and of
greater distance from the source.
Out Gain
The overall output level for the reverberation effect, and controls the level for both the
wet and dry signal paths.
Decay Time
The reverberation decay time (mid-band ÒRT
60
Ó), the time required before the
reverberation has died away to 60dB below its ÒrunningÓ level. Adjust decay time
according to the tempo and articulation of the music and to taste.
HF Damping
Adjusts lowpass Þlters in the reverberator so that high frequencies die away more
quickly than mid and low frequencies. This shapes the reverberation for a more natural,
more acoustically accurate sound.
Room Size
Choosing an appropriate room size is very important in getting a good reverberation
effect. For impulsive sources, such as percussion instruments or plucked strings,
increase the size setting until discrete early reßections become audible, and then back it
off slightly. For slower, softer music, use the largest size possible. At lower settings,
RoomSize leads to coloration, especially if the DecayTime is set too high.
Bass Gain
Adjusts bass equalizers in the reverberator so that low frequencies die away more
quickly than mid and high frequencies. This can be used to make the reverberation less
muddy.
Wet/Dry
0 to 100%wet
Out Gain
Off, -79.0 to 24.0 dB
Room Size
2.0 to 15.0 m
Diffusion
0 to 100%
Pre Dly
0 to 500 ms
Decay Time
0.5 to 100.0 ms
HF Damping
16 to 25088 Hz
Bass Gain
-15 to 0 dB
Build Time
0 to 500 ms
Lowpass
16 to 25088 Hz
Build Env
0 to 100%
LFO Rate
0.00 to 5.10 Hz
LFO Depth
0.00 to 10.20 ct