Custom Biquad Programming; What's A "Biquad; Using Custom Biquad Programming - miniDSP 2X4 HD User Manual

6.4 C
USTOM BIQUAD PROGRAMMING
Custom biquad programming is available in the PEQ and Crossover blocks. Its purpose is to allow you to directly
provide the low-level parameters aka biquad coefficients that control the digital filters of the processor, thus
providing an almost infinite degree of flexibility.
For example, you can create hybrid crossovers with staggered cutoff frequencies, create parametric EQ filters
beyond those provided in the easy-to-use "basic" interface, implement a Linkwitz transform, or mix crossover
and EQ biquads in the same block.
6.4.1

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, a0, b1, and b2. These numbers are called the coefficients.
6.4.2

Using custom biquad programming

Each crossover block and PEQ filter has a selector that switches it to advanced mode:
In advanced mode, the biquad coefficients can be pasted directly into the user interface. These coefficients must
be calculated using a design program – see
miniDSP Ltd, Hong Kong / www.minidsp.com
Biquad design software
/ Features and specifications subject to change without prior notice
below for suggestions.
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