-
Recent Posts
Archives
- January 2020
- April 2019
- September 2018
- August 2017
- May 2017
- January 2017
- December 2016
- September 2016
- February 2016
- September 2015
- January 2015
- March 2014
- January 2014
- October 2013
- June 2013
- May 2013
- April 2013
- March 2013
- February 2013
- December 2012
- November 2012
- May 2012
- March 2012
- January 2011
- December 2010
- November 2010
- July 2007
- March 2003
- February 2003
- August 2002
- January 1997
- November 1996
- October 1996
- August 1996
- July 1996
Categories
- Digital Audio (59)
- Aliasing (9)
- Convolution (3)
- Dither (7)
- Filters (23)
- DC Blocker (1)
- FIR Filters (7)
- IIR Filters (17)
- Biquads (11)
- Fourier (3)
- FFT (3)
- Impulse Response (5)
- Jitter (2)
- Oscillators (12)
- Phase (2)
- Reverb (2)
- Sample Rate Conversion (10)
- Sampling Theory (6)
- Effects (1)
- Envelope Generators (5)
- Math (2)
- MIDI (2)
- Source Code (10)
- Synthesizers (9)
- Uncategorized (5)
- Video (4)
- Widgets (12)
- Digital Audio (59)
Category Archives: IIR Filters
Biquad C++ source code
I don’t want to get into the business of teaching people how to code—there are a huge number of free resources available on the internet to that do that. But I’ll give a small taste for those trying to get … Continue reading
Posted in Biquads, Digital Audio, Filters, IIR Filters, Source Code
70 Comments
Biquad formulas
For fixed filters, we can plug biquad coefficients into our programs. But often, we need to calculate them on the fly, to user settings or changes in sample rate. As a companion to the biquad calculator, here are the formulas … Continue reading
Posted in Biquads, Digital Audio, Filters, IIR Filters
40 Comments
The bilinear z transform
The bilinear transform is the most popular method of converting analog filter prototypes in the s domain to the z domain so we can implement them as digital filters. The reason we are interested in these s domain filters is … Continue reading
Posted in Digital Audio, Filters, IIR Filters
23 Comments
The digital state variable filter
The digital state variable filter was described in Hal Chamberlin’s Musical Applications of Microprocessors. Derived by straight-forward replacement of components from the analog state variable fiter with digital counterparts, the digital state variable is a popular synthesizer filter, as was its … Continue reading
Posted in Digital Audio, Filters, IIR Filters
21 Comments
Biquads
One of the most-used filter forms is the biquad. A biquad is a second order (two poles and two zeros) IIR filter. It is high enough order to be useful on its own, and—because of coefficient sensitivities in higher order … Continue reading
Posted in Biquads, Digital Audio, Filters, IIR Filters
26 Comments