miniDSP Ltd, Hong Kong /
/ Features and specifications subject to change without prior notice
33
8.8.3
Parametric EQ file import (REW integration)
Multiple biquads in the parametric EQ block can be set at once by importing a coefficient file. The design
program must be set for a
96 kHz
sample rate. The number of filters is limited to a maximum of ten.
This example illustrates the correct file format:
biquad1,
b0=0.998191200483864,
b1=-1.9950521500467384,
b2=0.996920046761057,
a1=1.9950521500467384,
a2=-0.9951112472449212,
biquad2,
...
biquad3,
...
biquad10,
b0=1.0010192374642126,
b1=-1.9950555192569264,
b2=0.9940580112181501,
a1=1.995060938714333,
a2=-0.9950718292249559
Note that the last line must not have a comma at the end. If the file has less than ten biquads, then only that
number of biquads will be imported. For example, if importing a file with six biquads, the first six filters will be
set, and the last four will not be changed. (Note: if the last line ends with a comma, that counts as an extra
biquad.)
If the file contains more than ten biquads, then an error will be reported and no filters will be changed.
8.8.4
Biquad design software
The following programs can be used to design your biquad coefficients.
8.8.4.1
Biquad calculation spreadsheet
The community-developed biquad calculation spreadsheet allows many filter types to be calculated, including
notch filters, Linkwitz transforms, and filters with arbitrary Q-factor. Access this spreadsheet here (requires
Microsoft Excel):
•
http://www.minidsp.com/images/fbfiles/files/All_digital_coefs_v1-20101026.zip
8.8.4.2
Room EQ Wizard (REW)
Room EQ Wizard (REW) is a free acoustic measurement and analysis tool, available for Windows, Mac and Linux.
It can generate a bank of parametric EQ biquads based on a measurement. Room EQ Wizard can be downloaded
here:
•
http://www.roomeqwizard.com/#downloads
For guidance on using this feature, please refer to the app note
