miniDSP Ltd, Hong Kong /
/ Features and specifications subject to change without prior notice
35
3.10
C
USTOM BIQUAD PROGRAMMING
Available in
:
2x4 Advanced
,
2Way Advanced, 4Way Advanced, 2Way Advanced 21
Custom biquad programming is available in the PEQ and Crossover blocks of the
Advanced
plugins. Its purpose is
to allow you to directly provide the low-level parameters aka
biquad coefficients
that control the digital filters of
the miniDSP, thus providing an almost infinite degree of flexibility.
For example, you can create hybrid crossovers with more than one cutoff frequency, create crossover filter
types beyond those provided in the easy-to-use
“basic”
interface, implement a Linkwitz transform, or mix
crossover and filtering biquads in the same block.
3.10.1
What’s a “biquad?
A biquad is the basic unit of processing that is used to create digital filters. It can be described either with an
equation or with a signal flow diagram, as shown here:
A single biquad like this can perform a great many functions, including all of the functions of a single parametric
EQ filter, one 6 or 12 dB/octave high pass or low pass filter, and more. Biquads are combined in series
(cascaded) to create more complex filters. The function that each biquad performs is determined by just five
numbers:
a1
,
a2
,
b0
,
b1
, and
b2
. These numbers are called the
coefficients
.
3.10.2
Using custom biquad programming
If the plugin supports custom biquad programming, each crossover block or PEQ filter has a selector that
switches it to advanced mode:
