Page B-1

X-Rack EQ Module
B. The EQ Module

B.1 Connection

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. To select the appropriate
level for the equipment you are connecting to, please check the operating manual for
your mixer or DAW. The switch should be released for +4dBu operation: push it in for
–10dBV operation.

B.2 Operation

The EQ module is a 4-band equaliser that can be switched between two different
sets of curves, one based on the latest version of the classic SSLE Series EQ and the
other based on SSL’s G Series EQ.
The G-EQ button switches the EQ from ‘E’ operation to ‘G’ operation.
The IN button switches the entire section in and out of circuit.
B.2.1 Frequency Sections
The different frequency sections are as follows:
HF Section: Frequency range 1.5kHz – 22kHz
Gain ±20dB
LF Section: Frequency range 40Hz – 600Hz
Gain ±16.5dB
The HF and LFsections provide shelving equalisers with variable turnover
frequency and a gentle slope. Selecting the ‘G-EQ’ button provides a slightly steeper
slope for both sections with a degree of overshoot/undershoot (depending on
whether you are boosting or cutting) below the selected HFfrequency (or above the
selected LF frequency). Selecting ‘ ’ (‘Bell’) in either mode switches the equaliser
to a peaking curve.
HMF Section: Centre frequency 600Hz – 7kHz
Gain ±20dB
Continuously variable Q (0.7 – 2.5)
LMF Section: Centre frequency 200Hz to 2.5kHz
Gain ±20dB
Continuously variable Q (0.7 – 2.5)
Normally, at any Q setting, the bandwidth of the HMF and LMF sections varies with
gain, whereby an increase in boost or cut increases the selectivity of the EQ. This
type of EQ can sound effective when used at moderate settings; the gentle Q curve lends itself to the
application of overall EQ on combined sources and subtle corrective adjustments to instruments and
vocals.
When the EQ is switched to ‘G-EQ’ operation, at any given Q setting the bandwidth of the HMF and LMF
sections varies with gain such that an increase in boost or cut increases the selectivity of the EQ. This type
of EQ can sound effective when used at moderate settings; the gentle Q curve lends itself to the application
of overall EQ on combined sources and subtle corrective adjustments to instruments and vocals.
2
1
SEL
XR625
HF dB
HMF
LMF
dB
dB
LF dB
Q
Q
- +
- +
- +
- +
IN
G-EQ
KHz
KHz
22 1.5
10 5
2 15
7 .6
3 2
1 5
Hz
KHz
2.0 .2
1.0 .6
.3 1.6
600 40
220
60
OUT
IN
+4dBu
-10dBV
1
2