Rolls RP252 owner manual Operation, Introduction, Understanding Compression, Gating

OPERATION CONT

Raising the Signal Out of a Mix

Since reducing dynamic range can increase the average signal level and meter readings, a single track can be brought up out of a mix by boosting its level slightly and applying compression. Set the Threshold for 4 dB to 6 dB of compression.

Preventing Sound System Overload (Limiting)

Applications where an abolute maximum signal level must be set to avoid distor- tion or speaker damage, set the RP252 for Limiting. Limiting has been defined as a signal-to-compression ratio of 10:1 or more. Start with the Ratio at infinity:1, use a fast Attack and set the Threshold at 15 dB of compression or just a few dB below the clipping point of the sound system. At low levels the RP252 won’t do anything, but at higher levels the peaks will be limited to the Threshold point. Often, it is recommended the compressor/limiter be inserted just before the power amp, some systems even have a separate compressor/limiter on each output of the crossover.

INTRODUCTION

Thank you for choosing the ROLLS RP252 Compressor/Limiter/Gate. We recom- mend you take a moment and read through this manual as it provides information that will assist you in using your unit to it’s fullest potential.

The RP252 provides clear sonic quality and performance for the working musi- cian, DJ, studio operator, or anyone needing a friendly Compressor/ Limiter/Gate. The RP252 incorporates “soft-knee” compression and a 100 dB log averaging detector for amazing accuracy and smooth performance. The input connectors on the rear are designed to be used with -10 dB to +4 dB signal levels.

UNDERSTANDING COMPRESSION

The primary purpose of a compressor is to reduce and control the dynamic range of a program; from gentle narrowing of overall levels to limiting of peaks, to squashing all dynamics. Control is the main idea.

Another major use for compressors is to add punch to sloppy sounds. A compres- sor can do this by making the level of an instrument or a sound more consistent, or by reducing the volume of the more sustained sections of a note, which com- paratively accentuates the leading edge (Attack).

Sustain of instruments, especially guitars and bass can be achieved by raising the volume of low-level trailing edges of a note, which gives solid presence to the instrument. It also makes the note-by-note volume more even. All this is done by changing the gain in response to the signal. When the input is low in level, the compressor gain remains fixed, usually at 0 dB (unity gain) or greater. When the input increases above the threshold set by the compressor, the gain begins to decrease (i.e., the amount of gain reduction increases). For very large inputs, the gain can decrease considerably, Therefore, as signals get larger, the gain reduc- tion will increase, depending where the Threshold, Ratio and Output Level are set.

GATING

Gating is used to cut noise or “hiss” when there is no signal, or when the signal is below a certain threshold. Sometimes, such as with drums, the gate is used to stop all sound except when the drum is played, to remove background noise.

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