Yamaha CS1D Owner's Manual - Page 544

Appendices KNEE-This determines how compression is applied at the threshold point. When set to hard, compression at the specified ratio is applied as soon as the input signal level exceeds the specified threshold. For knee settings from 1 to 5, however, compression is applied gradually as the signal exceeds the specified threshold, creating a more natural sound. This is called soft-knee compression. ATTACK-This determines how soon the signal is compressed once the compressor has been triggered. With a fast attack time, the signal is compressed almost immediately. With a slow attack time, however, the initial transient of a sound passes through unaffected. Attack times from 1 to 5 milliseconds are a good place to start. RELEASE-This determines how soon the compressor returns to its normal gain once the trigger signal level drops below the threshold. If the release time is too short, the gain will recover too quickly causing level pumping (i.e., noticeable gain fluctuations). If it is set too long, the compressor may not have time to recover before the next high level signal appears, and it will be compressed incorrectly. Release times from 0.1 to 0.5 seconds are a good place to start. RATIO-This determines the amount of compression, that is, the change in output signal level relative to change in input signal level. For a 2:1 ratio, for example, a 10 dB change in input level (above the threshold) results in a 5 dB change in output level. For a 5:1 ratio, a 10 dB change in input level (above the threshold) results in a 2 dB change in output level. INPUT FILTER HPF/LPF-Select the filter that will be applied to the signal immediately before the compressor. When HPF (high pass filter) is on, the compressor will apply to the signal that has passed through the HPF, and the signal that has passed through the LPF will then be mixed in. Since with this setting only the high-frequency portion of the signal is compressed, the effect will function as a de-esser. For COMP ON and HPF ON LPF + HPF COMP SELF POST EQ When LPF (low pass filter) is on, the compressor will apply to the signal that has passed through the LPF, and the signal that has passed through the HPF will then be mixed in. With this setting, only the low-frequency portion of the signal is compressed. For COMP ON and LPF ON HPF + LPF COMP SELF POST EQ If you want the signal immediately after passing through the LPF or HPF to be used as the key-in signal for the internal compressor, select SELF POST EQ as the key-in signal. When the key-in signal is set to LEFT CH (when the key-in signal is taken from the previous-numbered channel), and if COMP is turned on and LPF or HPF is also turned on for the channel that is the source of the key-in signal, then the signal after passing through the filter will be output as the keyin signal. INPUT FILTER ON/OFF-This turns the input filter on/ off. If off, the LPF/HPF setting will be ignored. INPUT FILTER FREQUENCY-This sets the cutoff frequency of the LPF/HPF. (The LPF cutoff frequency and HPF cutoff frequency are always linked.) 12