Specifications

SPIRIT FEATURES
5
PIANO (7-8 OCTAVES)
BASS
BASS DRUM
BASS SAX
GUITAR
SNARE DRUM
MALE VOICE
FEMALE VOICE
FOOTSTEPS
20Hz 100 500 1k 5k 10kHz
Lo EQ
Hi EQ
20Hz 100 500 1k 5k 10kHz
Mid EQ frequency is sweepable on all Spirit mixers
(except Notepad)
15dB of cut or boost is available at low, mid and
high frequencies, giving plenty of control just
where it’s needed
20Hz 100 500 1k 5k 10kHz
+15dB
-15dB
+15dB
-15dB
THE GREAT BRITISH EQ
The EQ on a mixer’s channel strip is
both a valuable device for correcting
problems and a creative tool in mixing.
The EQ circuits on Graham Blyth’s
larger Soundcraft designs have
spawned many imitators, all trying to
recreate the warmth and musicality
that make the original EQ designs
popular with professionals around the
world. But why settle for an imitation
when you can have the real thing?
Part of the secret is careful positioning
of the high and low shelving filters in
the classic 3-band configuration. By
setting the HF shelving frequency
sufficiently high, and choosing the
right slope for the filter, the highest
band operates without interfering with
the swept mid-band, and this ensures
a natural sound and more effective
combination of frequency bands.
Similarly, the LF filter works only on
frequencies out of reach of the swept
band. Careful positioning of the LF
and HF bands also ensures that the
frequencies that are cut or boosted are
subjectively the most important ones.
The swept mid-band, with its Q (width
of the filter bell curve) of 1.5 operates
between the high and low bands. By
carefully choosing the right centre
frequency, Spirit’s swept EQ makes
it easy to locate and work on a
particular frequency range – either
to tune out a troublesome noise
such as feedback, or boost a range
of frequencies to emphasise the
character of an instrument.
Compare the typical frequency ranges of different
voices and instruments with the EQ ranges found
on Spirit mixers (shown below):
HIGH-PASS FILTERS
A High-Pass Filter is arguably one of
the most important features on a
channel strip, enabling unwanted low-
frequency noise to be removed from a
signal. Mics on stage can pick up a
good deal of rumble, and by using an
HPF you can still employ the LF part
of the channel EQ for creative work,
rather than using it for keeping stage
rumble at bay.
In order to be truly effective, however,
high-pass filters need a steep slope.
Spirit filters use an ultra-steep
18dB/octave slope (rather than the
more common 12dB/octave, shown by
a dashed line in the
diagram) which
means that all of the
lower frequencies are
attenuated – a less
steep slope allows
more bass
frequencies to slip through, which
is bad. By positioning the filters at
100Hz (-3dB), Spirit’s HPFs act on the
full range of lower frequencies that
cause clarity problems in mixing. The
more commonly-used 50Hz or 75Hz
filter points tend to work only on the
very lowest frequencies.
20Hz 100Hz
0dB
-3dB
STEREO INPUTS
Most contemporary electronic
instruments have stereo outputs, and
it’s always easier to deal with such a
stereo source with a stereo channel.
All your EQ and aux changes affect
both sides of the stereo signal equally,
and the sound remains balanced.
Stereo inputs don’t always give you
facilities such as EQ, but many Spirit
stereo channels have 2-band EQ with
carefully chosen frequencies that
enable effective adjustment in a live or
studio environment. On the SX, F1 and
FX8, the jack inputs to each stereo
channel are supplemented by a second
set of inputs on RCA phonos, with a
simple level control, providing still
more inputs in the compact frames.
exceptionally wide gain range of the
UltraMic™ (see diagram below) means
that it can just as easily amplify the
signal from a low-output ribbon mic as
a high-output condenser type. In fact
signals as hot as +22dBU can be
accepted, which means that it’s almost
impossible to push an UltraMic™ into
distortion. Over its entire 60dB gain
range, the noise and rejection of
interference of UltraMic™ are
exceptional – a careful look at the EIN
(Equivalent Input Noise) figures in the
specs show that the UltraMic™ is
almost silent. But then again, a careful
listen to any Spirit would tell you the
same thing.
The UltraMic™ input is also easy to
use, reflecting another important part
of the Soundcraft philosophy. With its
custom pot for gain control, the whole
of the pot’s travel gives useful
adjustment, whereas most mic pre-