Bus Compressor

The Threshold, Make Up, Attack, Release and Ratio controls are an emulation of the classic analogue SSL Bus Compressor module.

The Auto Release button automatically defines the release time according to the duration of the peak signal.

The Mix control allows a blend of the compressed and original uncompressed signals to be mixed together for parallel compression effects.

The Input Gain control adjusts the gain of the signal entering the compressor module.

A kick-down compression meter in the right side of the module provides visual feedback on the gain reduction action.

It should be noted that the knee point of the compressor, set with the Threshold control, purposely changes depending on the setting of the Ratio control. Decreasing the Ratio setting lowers the effective threshold, hence maintaining the perceived 'loudness' of the compressed signal.

De-Esser

The De-esser is a compression and filter system which can be used to remove sibilance or other frequency-dependent artefacts.

Definition: Sibilance is the resonance often found on vocal mics which can result in 'S' consonants becoming too pronounced.

Start by selecting which configuration of de-esser to use. The diagrams to the left explain the difference between Broad Band and Band Split de-esser configurations.

Set the Filter Type and Frequency to ensure the de-esser is responding to the right frequency range.

Note: The filter position within the de-esser depends on the compressor configuration, as shown left.

Move the Threshold control to set the detection level at the point where the De-esser only acts on sibilent peaks.

Move the Ratio knob to control how much sibilance is removed.

To listen only to the sibilance that is being removed, press the Solo button. This can be particularly helpful in ensuring that the threshold is correctly set.

An attenuation (Attn) meter is shown to the right of the Solo button.

Dynamic EQ

The Dynamic EQ is available with 1-, 2- or 4-bands of EQ, and the B1 to B4 buttons in the top right define which band is being edited in the rest of the window.

For each band, configure the Frequency (Freq) and Q of the EQ band to be compressed using left sliders; define the shape of the EQ filter using the button above the Freq slider.

Use the remaining sliders to control the action of the compressor; A kick-down compression meter in the right side of the module provides visual feedback on the overall gain reduction action across the four bands.

Note: Dynamic EQ has an auto knee that goes from 12dB when the compression ratio is 1:1 to 0dB when the ratio is ∞:1, ie it becomes progressively harder as ratio increases.

If a +ve EQ Gain is dialled in then the effect works in boost mode and EQ is triggered by signals below the Threshold level. Conversely, if a -ve EQ Gain is selected then the effect works in cut mode and EQ is triggered by signals above the Threshold.

Summary of effect of controls on the amount of gain added / gain reduction

Mode Controls
Gain Threshold Ratio
Lower Higher Lower Higher Lower Higher
Boost (gain added) Less More Less More Less More
Cut (gain reduced) More Less More Less More Less

To reset the band, press & hold the band's B button and select the Reset option from the drop-down list that appears.

To reset the whole module, press & hold the Reset FX button.

Sidechain

In normal operation the signal feeding the detection section (sidechain) of the Dynamic EQ is the same as the audio signal being processed by the module. However, it is possible to route a different signal to the sidechain input. This causes the signal routed through the effect to be processed based on the properties of the external 'key' signal. Use the Key Route button to route the key input signal and engage the Ext Key button to activate External Key mode.

It is possible to Solo the sidechain signal in various places. Use the Solo: button to choose the solo source point; the full range Pre-EQ point or after one of the Bands of EQ.

Gate

To activate the Gate, drag the Range down to a suitable level. The Range controls the dynamic range over which the gate operates.

The buttons in the top left allow you to select between RMS and Peak response mode.

The Thresh (threshold) defines the audio level at which the gate is opened to allow audio through.

Note: The level at which the gate opens is higher than the level at which it closes again. In other words, when the expander is opened, it stays open until the signal level crosses the quieter 'close' threshold. This is known as hysteresis and is very useful as it allows instruments to decay more naturally. The Thresh control refers to the 'open' threshold.

Hold controls the delay before the signal level starts reducing again, and Release controls how quickly the level then reduces. Attack controls the time taken for the Gate to 'recover' once the signal level is above the open threshold. 1.5ms (per 40dB) is a good Attack starting point, though percusive sounds may require an attack in the region of 0.1ms.

The 'traffic lights' towards the top-left indicate the gate's status: red indicates that the gate is closed (no audio is being passed), green that it is open (audio is being passed at full level), and yellow that it is opening or closing.

The meters at the right of the module show the module's input and output levels.

Listen Mic Compressor

The Listen Mic Compressor emulates the sound of the listen mic on an SSL E series console. Originally designed to prevent overloading the return feed from a studio communications mic, its fixed attack and release curves were eminently suitable for use on ambient drums mics, and it became a classic production tool.

Mix controls the balance of the compressed ('Wet') to uncompressed ('Dry') signal. Note that MakeUp only acts on the 'wet' part of the signal.

Comp controls the amount of compression, from 0 to 100%.

MakeUp controls the level compensation for the gain reduction.

To simulate the original narrow-band listen mic characteristic, activate the EQ button – to use the compressor on the full frequency range, leave EQ inactive.

Note: Listen Mic Compressor features very quick time constants. This means it is easily capable of producing distortion on low frequency material.

Multi Band Compressor

There are three bands of compression available within the Multi Band compressor; touch the Low, Mid or High buttons in the top left to define which band is being edited in the rest of the window. The sliders to the right of the buttons define the crossover frequencies between Low and Mid bands, and between Mid and High bands.

Each band's controls should be self-explanatory. The possible exception may be Max GR which limits the maximum amount of gain reduction, meaning that peaks which are well over the threshold are only attenuated up to the Max GR value. The rest of the dynamic range is left unaltered, and behaves as expected according to the other controls.

To reset a band, press & hold its B button;

To reset the whole module, press & hold Reset FX.

Sidechain

In normal operation the signal feeding the detection section (sidechain) of the Multi Band Compressor is the same as the audio signal being processed by the module. However, it is possible to route a different signal to the sidechain input. This causes the signal routed through the effect to be processed based on the properties of the external 'key' signal. Use the Key Route button to route the key input signal and engage the Key button to activate External Key mode.

It is possible to Solo the sidechain signal in various places. Use the Solo: button to choose the solo source point; the full range Pre-Filter point or after one of the Low, Mid or High bands.

Transient Shaper

The Transient Shaper uses an expander to add attack to the start of percussive sounds by increasing the amplitude of the attack portion of the signal whilst leaving the decay unchanged.

I/P Gain controls the detection level of the controller signal, and should be set so that only the transients you want to shape are detected. If this is set too low then the Shaper will do nothing; if it is set too high then the Shaper will detect too many transients, resulting in an exaggerated process, and the attack appearing too long. The default setting of 0dB should be a good starting point.
Note: I/P Gain doesn't directly affect the output signal's gain.

Amount controls the amount of the processed signal added to the unprocessed signal. This process can increase the peak level of a signal significantly so watch the output meter carefully.

Speed controls the length of time the added attack takes to fall back down to the normal signal level once it has reached the top of the attack phase.

Press Invert to invert the processed signal so that it is subtracted from the unprocessed signal. This has the effect of softening the attack, resulting in more body in a percussive sound.

Solo allows you to listen to the processed signal, to assist in the set up process.

Note: When the Invert and Solo buttons are both pressed, the signal will not be inverted.