Lexicon PCM 80 Mid Rt and Low Rt, Low Slope and Mid Slope, Crossover, Rt HC, Pre Delay, Infinite

PCM 80 User Guide Lexicon

Rvb Time The Reverb Time row, available in every algorithm, contains parameters that affect the time-based aspects of the reverb effect.

Mid Rt and Low Rt

Mid Rt sets the reverb time for mid-frequency signals. Because low frequency reverb time (Low Rt) is a multiplier of Mid Rt, Mid Rt acts as a master control for the reverb time.

Low Rt sets the reverb time for low-frequency signals, as a multiplier of the Mid Rt parameter. For example, if Low Rt is set to 2X, and Mid Rt is set to two seconds, the low frequency reverb time will be four seconds. For a natural- sounding hall ambience, we recommend values of 1.5X or less.

Low Slope and Mid Slope

These parameters are only available in the Inverse algorithm. Low Slope determines the shape of the reverb envelope for low frequencies. When set to 0, the level of low reverb remains unchanged over its Duration, then cuts off abruptly (depending on the amount of diffusion in use). Setting Low Slope above 0 causes the level of low-frequency reverb to rise smoothly from soft to loud until the sound is cut off. The greater the slope, the softer the initial reverberation and the more pronounced its rise. With negative values, the low frequency reverb drops from its initial level to a quieter one before cutoff. The lower the slope, the more pronounced the dropoff.

Mid Slope is similar to Low Slope, but applies to middle and high frequencies. The actual frequencies affected are determined by Crossover.

Crossover

Crossover sets the frequency at which the transition from Mid Rt to Low Rt takes place. This control should be set at least two octaves higher than the low frequency you want to boost. For example, to boost a signal at 100Hz, set Crossover to 400Hz. (This setting works well for classical music.) Crossover works best around 400Hz for boosting low frequencies, and around 1.5 kHz for cutting low frequencies.

Rt HC

Rt HC sets the frequency above which a 6dB/octave low-pass filter attenuates the reverberated signal. It does not attenuate the reflections. High frequencies are often rolled off with this parameter, resulting in more natural-sounding reverberation.

Pre Delay

Pre Delay adjusts an additional time delay between the input of signal and the onset of reverberation. The maximum range is 930ms. This control is not intended to mimic the time delays in natural spaces. In real rooms, the build-up of reverberation is gradual, and the initial time gap is usually relatively short. Natural spaces are best emulated by adjusting Spread for the desired effective predelay.

Infinite

In the Infinite algorithm, this control is provided to turn the infinite effect On or Off.

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