Original UA design dual-VCA dynamic processor for transparent gain reduction.

The Precision Buss Compressor is a dual-VCA-type dynamic processor that yields modern, transparent gain reduction characteristics. It is specifically designed to "glue" mix elements together for that cohesive and polished sound typical of master section console compressors.

A flexible and intuitive tool, the Precision Buss Compressor is intended primarily for controlling the final output of your mix, but can be usefully applied to a variety of sources from drum buses or overheads to vocal groups, or even as a channel compressor on individual tracks.

• Mix with UA's workhorse transparent dynamics processor
• Set a custom fade-out or fade-in of the mix between 1 and 60 seconds long
• Use the High Pass Filter to keep low-end punchy when compressing a mix
• Harness the Mix control for "parallel" style dynamics control

Precision Buss Compressor

Precision Buss Compressor Controls

Control knobs for the Precision Buss Compressor behave the same way as with all UAD plug-ins. Parameters with text values can be modified with text entry.

Filter

Filter regulates the cutoff frequency of the filter on the compressor's control signal sidechain. Removing low-frequency content from the sidechain can reduce excessive gain reduction and/or "pumping" on bass-heavy audio signals without reducing bass content of the audio signal itself.

The filter is an 18 dB per octave, coincident-pole high-pass filter. The available range is 20 Hz-500 Hz and Off.

Note: The Filter parameter affects the control signal (sidechain) of the compressor only. It does not filter the audio signal.

Threshold

This parameter determines the threshold level for the onset of compression. Incoming signals that exceed this level are compressed. Signals below the level are unaffected.

The available threshold range depends on ratio setting. At higher Ratio values, more headroom is available. Since the plug-in is designed primarily as a buss compressor, where signal levels typically run hotter than individual tracks, this feature increases the control resolution for fine-tuning these higher levels.

When Ratio is changed, the Threshold value is updated accordingly:

• When Ratio is set to 2:1, the Threshold range is -55 dB to 0 dB.
• When Ratio is set to 4:1, the Threshold range is -45 dB to +10 dB.
• When Ratio is set to 10:1, the Threshold range is -40 dB to +15 dB.

Note: When Ratio is changed, Threshold numerical values are updated but the Threshold knob position does not move.

As the Threshold control is decreased and more compression occurs, output level is typically reduced. Adjust the Gain control to modify the output to compensate if desired.

Ratio

Ratio determines the amount of gain reduction for the compressor. For example, a 2:1 ratio reduces the signal above the threshold by half, with an input signal of 20 dB being reduced to 10 dB.

The available Ratio values are 2:1 (default), 4:1, and 10:1.

Attack

Attack sets the amount of time that must elapse once the input signal reaches the Threshold level before compression is applied. The faster the Attack, the more rapidly compression is applied to signals above the threshold.

The Attack range is from 0.10 milliseconds to 32 milliseconds. The availability of relatively slow attack times (as compared to other compressors) is one factor that can provide the in-your-face-pumping quality that is so popular with large console VCA-style compressors.

Release

Release sets the amount of time it takes for compression to cease once the input signal drops below the threshold level.

The available range is from 0.10 seconds to 1.20 seconds, with Automatic release available at the full-clockwise position.

The Auto release characteristic for Precision Buss Compressor has a unique quality that is optimized for program material.

Slower release times can smooth the transition that occurs when the signal dips below the threshold, especially useful for material with frequent peaks. However, if you set too large of a Release time, compression for sections of audio with loud signals may extend to lengthy sections of audio with lower signals.

Fade

The Precision Buss Compressor provides a Fade function that, upon activation, automatically reduces the plug-in output to minimum within a specified time period. This function enables extremely smooth-sounding fade outs (and fade ins), plus it can be automated as well. The Fade function processes the signal at the output of the compressor.

Fade Set

Fade Set determines the amount of time that will pass between the Fade button being activated and the plug-in output level being reduced to minimum (or being raised to 0 dB in the case of a fade in). The available range is from 1.0 second to 60 seconds.

Fade times immediately reflect the current Fade Set value. Therefore a fade out that has already been initiated can be accelerated by changing Fade Set during the fade out. Conversely, a fade in can be accelerated by changing Fade Set during the fade in.

Note that although the Fade Set control itself has linear taper, the fade signal level that is output has an exponential curve.

Fade Switch

Activating the Fade switch initiates a fade out. The fade out time is determined by the Fade Set parameter.

The Fade switch flashes red when a fade out is in progress, and glows solid red when the fade out is complete (when the Fade Set time has elapsed).

Deactivating Fade initiates a fade in. During a fade in, the signal level is increased from the current level of attenuation to 0 dB of attenuation. The Fade switch flashes blue when a fade in is in progress, and is no longer illuminated when the fade in is complete (when the Fade Set time has elapsed).

Toggling the Fade switch causes an already active fade to reverse direction, without a jump in output level. The Fade Set rate is constant even if an active fade is interrupted. For example: If the Fade Set value is 30 seconds and a fade out is initiated, then Fade is clicked again after 20 seconds, it will take 20 seconds to fade back in.

Note: Shift+click the Fade button to instantly return the level back to 0 dB (this feature cannot be automated).

Input Level

Input controls the signal level that is input to the plug-in. Increasing the input may result in more compression, depending on the values of the Threshold and Ratio parameters.

The default value is 0 dB. The available range is ±20 dB.

Mix

The Mix control determines the balance between the original and the processed signal. The range is from 0% (dry unprocessed signal only) to 100% (wet processed signal only). The default value is 100%.

Output Level

Output controls the signal level that is output from the plug-in. The default value is 0 dB. The available range is ±20 dB.

Output controls both the dry unprocessed and wet processed signals (as determined by the Mix control).

Generally speaking, adjust the Output control after the desired amount of compression is achieved with the Threshold and Ratio controls. Output does not affect the amount of compression.

Level Meters

The stereo peak/hold Input and Output Meters display the signal level at the input and output of the plug-in.

The range is from -30 dB to 0 dB. Signal peaks are held for 3 seconds before resetting.

Gain Reduction Meter

The Gain Reduction meter displays the amount of gain reduction occurring within the compressor. More blue bars moving to the left indicate more gain reduction is occurring.

The meter range is from -16 dB to 0 dB. Signal peaks are held for 3 seconds before resetting.

Power

The Power switch determines whether the plug-in is active. Click the toggle button or the UA logo to change the state.

When the Power switch is in the Off position, plug-in processing is disabled and UAD DSP usage is reduced (unless UAD-2 DSP LoadLock is enabled). When the plug-in is bypassed with this switch (but not by the host bypass), the I/O meters and the Input Level knob remain active.