Aphex EX BB 500 - Manual (Page 7)

Page 7
Input
Sidechain
Processing
Original
Signal
Output
SIMPLIFIED SIDECHAIN DIAGRAM
As illustrated above, the unit splits the input signal into two paths.
One path goes directly to the output unmodified, while the other
path, known as a sidechain, goes through the Aural Exciter circuit
which is comprised of a tunable high pass filter and a harmonics
generator. The Aural Exciter circuit applies frequency dependent
phase shift and transient discriminate harmonics. The output of
the Aural Exciter’s harmonic circuit is mixed back with the unmodi-
fied signal but much lower in level. When used at nominal settings,
the Aural Exciter circuit does not add significant level to the original
signal. Even though the added information is low in level, the per-
ception is a dramatic increase in mid and high frequencies.
The EX•BB 500 also incorporates another exclusive Aphex patent,
Big Bottom, providing a stronger, more powerful bass, increased
sustain and density without an increase in the peak output. While
static bass-boost EQ’s and subharmonic generators will increase
the bass energy level, the resultant large boost in peak level often
increases overload distortion. Big Bottom resembles the Aural
Exciter in that a processed signal is mixed back into an unmodified
signal to produce an enhanced output signal. The sidechain path
goes through the Big Bottom circuitry, comprised of a variable low-
pass filter and a phase and dynamics processor.
Big Bottom circuitry dynamically contours the bass response of a
complex range of shapes in the 50Hz to 200Hz range. Big Bottom
increases the perception of low frequencies without significantly
increasing the maximum peak output. The bass frequency response
is dynamically optimized to isolate and enhance the lowest bass
frequencies to provide a deeper and more resonant bass.
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