Kurzweil K2661 - 3 Band Enhancer; 3 Band Spectral Modifier; One Channel of 3 Band Enhancer

10-224
KDFX Reference
KDFX Algorithm Specifications
960 3 Band Enhancer
3 band spectral modifier
PAUs: 2
The 3 Band Enhancer modifies the spectral content of the input signal by boosting existing spectral
content, or stimulating new ones. First, the input is non-destructively split into 3 frequency bands using 6
dB/oct hipass and lopass filters (Figure 1). The high and mid bands are separately processed to add
additional high frequency content by using two nonlinear transfer functions. The low band is processed by
a single nonlinear transfer to enhance low frequency energy. Each band can also 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 with the KDFX 24 khz sampling rate. Using
what we know about psychoacoustics, phase shifting, or delaying certain frequency bands relative to
others can have useful affects without adding any gain. In this algorithm, delaying the lower bands
relative to higher bands brings out the high frequency transient of the input signal giving it more
definition. Conversely, delaying the higher bands relative to the lower bands brings out the low frequency
transient information which can provide punch.
Figure 10-117 One channel of 3 Band Enhancer
The nonlinear transfers applied to the high and mid bands can be used to generate additional high and
mid frequency content when Xfer1 and Xfer2 are set to non-zero values. As the value is scrolled away from
0, harmonic content is added in increasing amounts. In addition, setting both positive or negative will
respectively impose a dynamically compressed or expanded quality. This type of compression can bring
out frequencies in a particular band even more. The expanding quality is useful when trying to restore
transient information. More complex dynamic control can be obtained by setting these independent of
each other. Setting one positive and the other negative can even reduce the noise floor in some
applications.
The low band has a nonlinear transfer that requires only one parameter. Its affect is controlled similarly.
Parameters
Page 1
In/Out In or Out Out Gain Off, -79.0 to 24.0 dB
CrossOver1 17 to 25088 Hz
CrossOver2 17 to 25088 Hz
Crossover
Hi
Mid
Lo
XFer
XFer 1
XFer 1
XFer 2
XFer 2
Delay
Delay
Delay
L Input L Output
Drive Mix
Out Gain