Category Archives: Widgets

Biquad calculator v3

Posted on September 2, 2021 by Nigel Redmon

The latest version of the biquad calculator. It also takes on the functionality of the frequency response grapher:

Posted in Biquads, Digital Audio, Filters, Widgets | Tagged | 56 Comments

AM widget

Posted on October 2, 2020 by Nigel Redmon
Posted in Amplitude Modulation, Widgets | Leave a comment

Filter frequency response grapher

Posted on December 8, 2016 by Nigel Redmon

Here’s a tool that plots frequency response from filter coefficients. Hz linearlog 10log 2 Plot auto40 dB30 dB20 dB10 dB0 dB-10 dB-20 dB-30 dB-40 dB Max 60 dB80 dB100 dB120 dB140 dB160 dB180 dB Range a coefficients (zeros) b coefficients … Continue reading →

Posted in Biquads, Filters, FIR Filters, IIR Filters, Widgets | 15 Comments

Cascading filters

Posted on September 29, 2016 by Nigel Redmon

Sometimes we’d like to cascade biquads to get a higher filter order. This calculator gives the Q values for each filter to achieve Butterworth response for lowpass and highpass filters. Order: 234567891011121314151617181920 Q values: You can calculate coefficients for all biquad … Continue reading →

Posted in Biquads, Filters, IIR Filters, Widgets | 40 Comments

Dither widget

Posted on March 15, 2014 by Nigel Redmon
Posted in Digital Audio, Dither, Widgets | Leave a comment

Pole-Zero placement v2

Posted on October 28, 2013 by Nigel Redmon

Pair Pole mag Pole angle Pair Zero mag Zero angle Sample rate (Hz) linearlog Plot A new pole-zero calculator An JavaScript remake of the old Java-based pole-zero placement applet—visit that page for tips on pole-zero locations for standard biquads. The … Continue reading →

Posted in Biquads, Digital Audio, Filters, IIR Filters, Widgets | 15 Comments

Biquad calculator v2

Posted on October 13, 2013 by Nigel Redmon

Type:lowpasshighpassbandpassnotchpeaklow shelfhigh shelfone-pole lpone-pole hp Plot:linearlog Sample rate (Hz) Fc (Hz) Q Gain (dB) Here’s an update of the biquad calculator. It adds one-pole highpass and lowpass filters, and frequency, Q, and gain sliders. The sliders cover the range of … Continue reading →

Posted in Biquads, Digital Audio, Filters, IIR Filters, Widgets | 96 Comments

Envelope generators—ADSR widget

Posted on June 23, 2013 by Nigel Redmon

Attack Decay Sustain Release Attack Curve Decay/Release Curve Plot:linearlog This is the widget I used in making the ADSR video. It’s a JavaScript recreation of my C++ source code.

Posted in Envelope Generators, Synthesizers, Widgets | 22 Comments

A biquad calculator

Posted on December 20, 2010 by Nigel Redmon

Something useful: a biquad filter coefficient calculator… Continue reading →

Posted in Biquads, Digital Audio, Filters, IIR Filters, Widgets | 37 Comments

A closer look at upsampling filters

Posted on December 11, 2010 by Nigel Redmon

Interpolation type:NoneZero-order holdLinearSinc 1Sinc 2Sinc 3  Show impulse response Sweep! In this demonstration, we generate a sine wave sweep from low in the audio band to near the Nyquist Frequency, which is half the sample rate. You can view it … Continue reading →

Posted in Aliasing, Digital Audio, Filters, FIR Filters, Impulse Response, Sample Rate Conversion, Widgets | 1 Comment