Solid State Logic X-Logic Series Rack Dynamics Module, Compressor/Limiter Section, D-1

X-Rack Dynamics Module

D. The Dynamics Module

D.1 Connection

SYV

Nu

The module input and output gains can be set to operate at a nominal level of either +4dBu or –10dBV, using a switch on the connector panel. Select the appropriate level for the equipment you are connecting to. If in doubt experiment!

To check the input and output gains, set the compressor Ratio and Threshold controls fully clockwise and send a signal close to the nominal operating level of your mixer or DAW to the dynamics module. The lower three LEDs of the compression meter should light if the input level matches the selected operating level. Release the switch for +4dBu operation: push it in for –10dBV operation.

D.2	Operation
	Each dynamics module comprises a compressor/limiter and a gate/expander, both								XR618
	of which use the same gain element.
	The IN button	G	switches the entire section in and out of circuit.
D.2.1	Compressor/Limiter Section				H					∞
	RATIO – When turned to 1:1, the compressor/limiter section is inactive. Turning								G
									H
	the control clockwise increases the compression ratio, giving a true limiter at the
	fully clockwise position. The compressor normally has an ‘over-easy’ characteristic.									8GF	CHF
	Pressing the PK button switches this to peak sensing, and replaces the ‘over-easy’
	characteristic with a hard knee.
									FDG	K	HF
	THRESHOLD –		Whenever		a	signal exceeds	the	level set by this control, the
											GK
	compressor will		start	to act		at the ratio	set	by the RATIO control. The			GF
											M
	THRESHOLD and RATIO controls also provide automatic make-up gain, so as
											I
	you lower the threshold and introduce more compression, the output level is
	increased, maintaining a steady output level regardless of the amount of
	compression.								F	KF
	FST ATK – Normally the attack time is program dependent (3mS – 30mS). Press this								I
	button to select a fixed fast attack time (3mS for 20dB gain reduction).									CIF	8GF
	RELEASE – Sets the time constant (speed) with which the compressor returns to
	normal gain settings once the signal has passed its maximum.								FDG	K
D.2.2	Gate/Expander Section			I					G	F	K
	This section can act as a ∞ :1 Gate or as a 2:1 Expander when the EXP button is
	pressed.
	RANGE – Determines the depth of gating or expansion. When turned fully
	anticlockwise (Range = 0), this section is inactive. When turned fully clockwise, a
	gate depth of 40dB can be obtained.

THRESHOLD – Determines the level at which the gate opens or below which gain reduction begins (EXP selected), adjustable from +10dBu to –20dBu. Variable hysteresis is incorporated in the threshold circuitry to prevent spurious triggering of the gate when the signal is close to the threshold level. This means that the signal has to decay roughly 2dB below the threshold level before the gate will start to close.

Page D-1