Source Audio Soundblox Pro Classic Distortion Pro - Manual (Page 4)

Theory of Operation | 7 6 | Theory of Operation
MIDRANGE control
This control provides
12 dB of cut or boost to a midrange frequency band
which is approximately two octaves wide. The exact frequency is different
depending on which distortion has been selected.
Graphic EQ
The
7 -band graphic equalizer can be adjusted in 1 dB steps. Moving
bands up or down 1 dB can make a significant change to the sound.
So don’t think that you have to make big adjustments with the EQ . The
graphic EQ is at the end of the processing, after the distortion.
CLEAN BOOST / EQ
In this setting, the distortion curves are straight lines (meaning there is
no distortion). The graphic
EQ can be adjusted to taste. The MIDRANGE
control is also still active in this mode. The DRIVE controls will need to be
set around 9 o’clock to ensure that the signal doesn’t clip. Although the
distortion curves are flat, there still comes a point where the signal will
clip if the
DRIVE is turned up too far.
If both DRIVES are turned up, there will be a raspy sound as the signal
peaks are hard clipped. In general, this doesn’t sound very good. How-
ever, if the
DRIVE controls are cranked, the resultant distortion is not bad
at all despite consisting only of digital hard clipping. Don’t believe that?
Give it a try. This distortion sound can be improved by rolling off the
MID-
RANGE control and using the graphic EQ to further shape the sound.
THEORY OF OPERATION
The Classic Pro features distortion effects that are re-creations of popu-
lar pedal and amplifier based distortions. We have chosen names for the
distortions that will be suggestive of the sounds you will get with all of
the controls in the central part of their range. We are not trying to imply
exact simulations of the various analog effects. Rather, this is a different
take on classic sounds based more upon evaluating the sounds by ear
and overall circuit function instead of attempting to do a mathematical
model or emulation (which, incidentally, we think is really not possible
for distortions).
The following list describes the major new features available in the
Classic Pro:
Architecture
Most analog fuzzes and distortions have multiple points where the signal
passes through a distortion circuit, an op-amp, a transistor, or a diode.
We provide two such cascaded distortion functions, each with a
DRIVE
control in front of it. The MIDRANGE control sits between the two distor-
tions. The graphic EQ is at very end of the chain.
DRIVE controls
The DRIVE knobs control the gain of the two distortion curves. You can
obtain the same amount of overall gain through the system with various
combinations of the two controls: one high and the other low, both in the
middle, etc. However, the resulting sound will be different. Distortion
from
DRIVE 1 has more EQ applied to it than the distortion from DRIVE 2 .
Essentially, you just have to experiment and listen to the results.
If the MIDRANGE control is increased, a hotter signal will be applied to
the second distortion curve and you might need to reduce DRIVE 2
accordingly. Maxing out both DRIVE controls will probably be excessive.
Most of the distortion flavors sound better with more moderate DRIVE
settings. DRIVE 1 and your guitar volume both directly control the signal
applied to the first distortion curve. Using a higher setting of DRIVE 1 , you
can set your guitar volume quite low for a cleaner tone and increase your
guitar volume when you need more distortion.