HallVerb is an implementation of “mverb”, an open-source algorithmic reverb by Martin Eastwood (see https://github.com/martineastwood/mverb). Our first implementation was called “Reverb-M”, and this is still reflected in the GUI, although we changed the effect name to “EmVerb”.

Although Mr. Eastwood's mverb code was originally published under the terms of the GNU General Public License, he very kindly granted us permission to incorporate it into Unify as a built-in effect.

EmVerb has eight control knobs, each corresponding to an identically-named parameter available for modulation, as follows. Note all parameters are “normalized” values between 0.0 and 1.0.

• Damping: 0.0 (no damping, very bright) to 1.0 (max damping, very dark), default 0.5. Amount of low-pass filtering in the feedback path.
• Density: 0.0 to 1.0, default 0.75. Higher values create a smoother sound.
• Bandwidth: similar to Damping, but sets the range of frequencies subject to reverberation. Default 1.0.
• Decay: 0.0 (short tail) to 1.0 (long tail), default 0.75.
• Predelay: amount by which wet signal is delayed relative to dry, 0.0 (none) to 1.0 (about 0.5 sec), default 0.0.
• Room Size: simulated room size, 0.0 (very small) to 1.0 (large), default 0.8.
• Mix: Dry/Wet mix, 0.0 (all dry) to 1.0 (all wet), default 0.5.
• Early/Late Mix: mix of early and late reflections, 0.0 (early only) to 1.0 (late only), default 0.5.

• The higher the Room Size setting, the longer the reverb tail rings out
• Decrease Damping for a bright sound, set high for a dark sound (also reduces tail length strongly).
• Experiment with Damping, Bandwidth, Decay and Room Size settings to balance tail length and tonal balance.
• When using this or any reverb effect on an AUX layer, set (Dry/Wet) Mix to 1.0. When using as an in-line effect on an INST layer, you would normally keep the Wet Level below 0.5. Low values can be subtle but quite effective.