FXAlg #959: 2 Band Enhancer
Algorithm Reference-158
FXAlg #959: 2 Band Enhancer
2-band spectral modifier
Allocation Units:
1
The 2 Band Enhancer modifies the spectral content of the input signal primarily by brightening signals with little or
no high frequency content, and boosting pre-existing bass energy. First, the input is non-destructively split into two
frequency bands using 6 dB/oct hipass and lopass filters. The hipassed band is processed to add additional high
frequency content by using a nonlinear transfer function in combination with a high shelving filter. Each band can
then be separately delayed to sample accuracy and mixed back together in varying amounts. One sample of delay
is approximately equivalent to 20 microseconds, or 180 degrees of phase shift at 24 kHz. Using what we know about
psychoacoustics, phase shifting or delaying certain frequency bands relative to others can have useful effects
without adding any gain. In this algorithm, delaying the lopass signal relative to the hipass signal brings out the
high-frequency transient of the input signal giving it more definition. Conversely, delaying the hipass signal
relative to the lopass signal brings out the low-frequency transient information which can provide punch.
The transfer applied to the hipass signal can be used to generate additional high-frequency content when set to a
non-zero value. As the value is scrolled away from 0, harmonic content is added in increasing amounts to brighten
the signal. In addition to adding harmonics, positive values impose a dynamically compressed quality, while
negative values sound dynamically expanded. This type of compression can bring out frequencies in a particular
band even more. The expanding quality is particularly useful when trying to restore transient information.
Parameters:
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In/Out
When set to ÒInÓ the effect is active; when set to ÒOutÓ the effect is bypassed.
Out Gain
The overall gain or amplitude at the output of the effect.
CrossOver
Adjusts the -6dB crossover point at which the input signal will be divided into the
hipass band and a lopass bands.
Hi Drive
Adjusts the gain into the transfer function. The affect of the transfer can be intensiÞed or
reduced by respectively increasing or decreasing this value.
Hi Xfer
The intensity of the transfer function.
Hi Shelf F
The frequency of where the high shelving Þlter starts to boost or attenuate.
In/Out
In or Out
Out Gain
Off, -79.0 to 24.0 dB
CrossOver
17 to 25088 Hz
Hi Drive
Off, -79.0 to 24.0 dB
Hi Xfer
-100 to 100%
Hi Shelf F
16 to 25088 Hz
Hi Shelf G
-96 to 24 dB
Hi Delay
0 to 500 samp
Lo Delay
0 to 500 samp
Hi Mix
Off, -79.0 to 24.0 dB
Lo Mix
Off, -79.0 to 24.0 dB
