Lexicon musical instrument Echo Level Left/Right, Echo Time Left/Right, Spread, Diffusion

DESCRIPTION OF PARAMETERS

ECHO LEVEL LEFT/RIGHT

In many real spaces, distinct reflections and echoes are an important part of the sound. Although many natural-sounding environments use little or no echo there are some cases where they can be used to help define the size of the space or to give a slapback or doubling of the diffused sound. The echo signals are fed from the diffusion section to the left and right output with independent control of the left and right echo levels. These levels, when used, should be set to lower than the original signal with values in the range from -6 dB to -24 dB the most useful.

ECHO TIME LEFT/RIGHT

For natural echo sounds, the setting of the echo time is very dependent on the size of the reverberating space. For slapback settings used to enhance the original sound, set the echo time in the range of 60 to 85 milliseconds. The left and right echoes should be set exactly the same or at least 10 milliseconds apart from each other to avoid any comb filter coloration.

SPREAD

Spread works to control the profile of initial reverberant-energy growth. Spread stretches or compresses the energy contour in time to make reflections closer together or further apart. Spread will change the feel of the reverberant space and gives the user some latitude to fit the reverb to the source material. It may be advisable to use a moderately low value for spread to create a bit of space around the original signal. For non-percussive, single instrument reverb settings higher values of Spread can add a perceived widening and thickening to the material.

DIFFUSION

Diffusion models the effect of irregular wall surfaces in a room by changing echo density. Very low values produce sharp, discrete, early reflections. Higher values produce groups of reflections that are smoother but less articulated. This is an important parameter to adjust to create a natural feel to the reverb. Higher Diffusion settings are common for the most natural-sounding environments. Lower settings are useful only on specialized reverbs where the source material is not percussive such as vocals and horns.

BASS BOOST

Bass Boost controls the low frequency reverberation time relative to the RT60 parameter. If, for example, Bass Boost is set to 2.0X and RT60 is set to 1 second, the effective low frequency is extended to 2 seconds. For natural- sounding results, use settings of 1.5X or less. For longer RT60 settings and larger room sizes the maximum effective value for the BassRT parameter is scaled back to avoid instability. BassRT values less than 1.0X produce a low frequency RT that is shorter than RT60 which can be used to create reverbs without low rumble. This can be desirable for fitting a reverberated track such as vocals within a desired frequency range for the final mix.

BASS FREQ (FREQUENCY)

Bass Freq sets the frequency at which the transition between RT60 and Bass Boost takes place. Values in the range of 200 Hz to 400 Hz works best for natural-sounding reverb. Except for special effects, there is seldom a need for this parameter to exceed 500 Hz.

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