The reverberation itself can be influenced by four main parameters.
PREDELAY
The PREDELAY knob determines the delay between the direct signal and the reverberated signal. The predelay time can be set between 0 and 160 ms. A predelay takes care of the fact
that the reflections in a room don’t happen immediately after the direct signal can be heard. The larger the room, the longer it takes for the reverberation to build up. Hence, we take a short predelay time for smaller
rooms and longer predelay times for larger rooms. The predelay time is also visualized in the time response display. The orange bar on the left represents the direct signal while the blue hill in the middle represents
reflections. Modifying the predelay time moves the blue hill towards or away from the orange bar.
A good choice for the predelay time is the time it takes sound to travel
a distance that corresponds roughly half the length of the room we want to simulate. For example, for a room of length 15 meters, we choose a predelay time of 22 ms.
DECAY
Another important parameter is the decay time which can be adjusted using the DECAY knob between 50 ms and 10 seconds. The decay time is measured as follows. Assume that we are standing in a room,
clapping our hands a single time (generating a signal with peak at 0 dB). The decay time is the time it takes until the level of the reverb signal (the diffuse reflections of the room) has reached -60 dB, which
is roughly equivalent to silence. Larger rooms tend to have larger decay times than smaller rooms, so again, this value corresponds (to some extent) to the size of the room we want to simulate but it also
depends on the amount of sound absorbed at walls and objects inside the room. The decay time is also visualized in the time response display (see above). Note that for larger decay times (when the sum
of predelay time and decay time exceeds 400 ms) the blue “reflection hill” extends (invisibly) to the right of the display.
DENSITY
Another characteristic property of a room is its reflection density. This can roughly be measured as the number of reflections that are generated by the room in a certain interval of time. The reflection
density depends on the wall surfaces and the objects in the room. If reflection at walls and objects is highly diffuse then reflection density is high since every time sound hits a wall it is reflected in many
different directions. On the hand, if walls have hard, highly polished surfaces then reflection density will be low. If the DENSITY knob is turned fully left then single reflections can be heard with some sound
material. If it is turned fully right then reflections have a high density and even short signals generate smooth and dense reverb tails. The DENSITY parameter is also visualized in the time response display: it
determines the brightness of the blue “reflection hill”.
QUALITY
Reverb.it lets you adjust reverb quality to your needs. The term quality
refers here to the amount of randomness in the reverb tail. In most “artificial” reverb devices one can find reflection patterns that repeat itself. If these patterns are too short then the reverb may sound
artificial and repetitive. In contrast to most other reverb devices, Silverspike Reverb.it lets you adjust the length of these patterns to your specific needs. Note, however, that already the lowest quality
setting (50%) delivers a quality that is comparable to all other native reverb plugins available at the time being.
A low quality setting is always sufficient for shorter decay times, larger
quality settings are useful for longer decay times in order to achieve more transparency and realism. You need to experiment with this knob since it may also depend on your sound material how much quality for
a certain decay time is needed. Higher quality settings are usually only needed if your sound material has silent parts at the beginning of which the reverb tail is clearly audible. For example, an “a capella”
song will most probably have such parts.
In any case, a good strategy is to run with low quality during rough mixes and to increase quality as desired when doing the final offline mix
since the quality setting influences the CPU usage of this plugin. See the