The Vienna Suite Compressor lowers the level of the input when it exceeds the threshold. The amount of attenuation is determined by the Attenuation / Ratio and input level. When the input level goes above the threshold, attenuation is added gradually to reduce distortion. Usually, the incoming signal is identical to the input to the gain reduction stage. The compressor's attack time determines how fast the compression is applied – this way you can sculpt the attack of your instruments, making them softer or more aggressive. The release time determines the time it takes the compressor to decrease the applied gain reduction. Depending on the length of the release time you can minimize the "sonic body" of an instrument in comparison to the attack sound, or you can apply extremely short release times to emphasize it.
The Vienna Suite Compressor can shape the controlling signal (aka "Sidechain") to allow for even more musical compression modes.
Additionally, you can use the Compressor as a Sidechain plug-in within your sequencer.
Threshold: is the level above which the signal is reduced. A low threshold means that a larger portion of the signal will be processed.
Sidechain: Choose between Low Cut (120 Hz), High Cut (4 kHz) (both at 12 dB/oct) and High Boost (+6 dB at 4 kHz). The Sidechain works exclusively with the internal sidechain filter. Use low cut when the signal starts to "pump" due to high energy in the lower frequencies. Use high boost when you want to get rid of excessive high-frequency content, e.g. Voices with strong "sss" and "shhhh". Use the high cut when the signal's attacks begin to sound lifeless and flat, especially when using fast attack times. The settings in the Sidechain only affect the Compressor's controls, NOT the signal itself!
Sidechain Solo: Solos the sidechain signal.
Waveform Data Display: Shows the input and output signals in real-time.
Attack: Sets the time the compressor needs to increase the gain reduction to reach the level determined by the ratio. Values: 0.1 – 500 ms.
Release: The 'release phase' is the period when the compressor decreases gain reduction to the level determined by threshold and ratio (or to zero, once the level has fallen below the threshold). Values: 10–5000 ms.
Attenuation: Displays the current amount of compression applied to the signal.
Ratio: The ratio determines the input/output ratio for signals above the threshold. For example, a 3:1 ratio means that a signal overshooting the threshold by 3 dB will leave the compressor 1 dB above the threshold.
Opto: Activates the optical release simulation, resulting in a more "breathing" sound. Compared to the same settings without Opto Mode, a little less compression will be applied to the signal.
Fat: Activates a process which makes the signal sound "thicker", similar to tape compression. When FAT mode is on, the sound is hard-clipped at 0 dB. With a certain configuration (when the signal may exceed 0 dB), this may cause distortion in the attack segment. In this case, please switch off the make-up gain or turn off FAT mode.
Make-up: Automatically compensates for the gain loss in the compression based on the current threshold, ratio and attack settings.
Output: Determines the signal's output volume.