dbx Pro QUANTUM user manual Detailed Parameters Section Multiband Compression

QUANTUM

Detailed Parameters Section 4

4.1 Multiband Compression (cont.)

Threshold -60 to 0 dB (per band or global)

Threshold is the signal level at which the QUANTUM starts to compress. If the threshold is set to -10 dBFS, then any signal larger than -10 dBFS is compressed, while any signal that has a level lower than -10dBFS is left at the same level. Light compression is where only the largest parts of the signal go over the threshold. Very heavy compression can be achieved by setting the threshold low enough so that almost the entire signal content is over the threshold. For most signals, the most natural compression is achieved when most of the signal content remains just below the threshold and only the peaks cross the threshold.

Ratio 0.75 to Inf:1 (per band or global)

Ratio is the amount the QUANTUM reduces the signal level of the sound that is above the threshold. A 2:1 ratio means that if the incoming signal is 2dB over the threshold the QUAN- TUM will compress the signal, and outputs a signal that only goes 1dB over the threshold. For light compression choose a lower ratio. For heavy compression a higher ratio is used. By set- ting the ratio at less than 1:1, the signal will be expanded rather than compressed. The QUAN- TUM will actually output a signal larger then the input. At a ratio of 0.75:1, if a signal goes over the threshold by 0.75dB the unit will output a signal that is 1 dB over the threshold.

Gain -20 to +20 dB (per band or global)

This is used to compensate for the gain lost during compression. By using heavy compression on a signal and then boosting the signal with the output gain we can than create a signal that sounds much louder than it was.

Attack 0.1 m Sec to 200 m Sec (per band or global)

Attack is how fast the compressor starts to compress the signal after it passes the threshold. Fast attack is useful when dealing with lots of fast transients. The attack control is not active when in auto mode.

Hold 0 to 500 m Sec (per band or global)

Hold is the time the QUANTUM remains in compression after the signal has dropped below the threshold. A longer hold time is useful in smoothing out the sound when compressing several fast peaks that are fairly close together in time. In general, some hold time helps to make the compression sound more natural but too much can over compress your signal making for an unwanted drop in level. The hold control is not active while in auto mode.

Release 360 dB / Sec to 5 dB / Sec (per band or global)

Release is how fast the QUANTUM comes out of compression. The release is in dB per second. For example, if release is set to 5 dB /sec, signal at 10dB of gain reduction, release time is 2 seconds. Too fast a release time can result in an audible volume jump, while too slow a release time can result in the compression of a signal that is not above the threshold. This can cause volume drops in your signal that may not be desired. The release control is not active while in auto mode.

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QUANTUM User Manual 31