Two-pole, two-zero filter biquad~ implements a two-pole, two-zero filter using the following equation:

y[n] = a0 * x[n] + a1 * x[n-1] + a2 * x[n-2] - b1 * y[n-1] - b2 * y[n-2]

You can specify the coefficients a0, a1, a2, b1, and b2 as signals or floats (if you make the filter explode by making the b coefficients too high, you can recover (after lowering them) with the clear message, or by turning the audio on and off). Cycling '74 MSP MSP Filters Input TEXT_HERE Input Gain (Filter coefficient a0) TEXT_HERE Filter coefficient a1 TEXT_HERE Filter coefficient a2 TEXT_HERE Filter coefficient b1 TEXT_HERE Filter coefficient b2 TEXT_HERE Output TEXT_HERE a0 coefficient initial value Set the initial value for the a0 filter coefficient. If a signal is connected to the second inlet, the coefficient supplied as an argument is ignored. a1 coefficient initial value Set the initial value for the a1 filter coefficient. If a signal is connected to the third inlet, the coefficient supplied as an argument is ignored. a2 coefficient initial value Set the initial value for the a2 filter coefficient. If a signal is connected to the fourth inlet, the coefficient supplied as an argument is ignored. b1 coefficient initial value Set the initial value for the b1 filter coefficient. If a signal is connected to the fifth inlet, the coefficient supplied as an argument is ignored. b2 coefficient initial value Set the initial value for the b2 filter coefficient. If a signal is connected to the sixth inlet, the coefficient supplied as an argument is ignored. Function depends on inlet Converted to float.

The coefficients in inlets 2 to 6 may be specified by a number instead of a signal. If a signal is also connected to the inlet, the number value is ignored. Function depends on inlet The coefficients in inlets 2 to 6 may be specified by a float instead of a signal. If a signal is also connected to the inlet, the float is ignored. Set the filter using a list of five filter coefficients The five filter coefficients can be provided as a list in the left inlet. The first number in the list is coefficient a0, the next is a1, and so on. If a signal is connected to a given inlet, the coefficient supplied in the list for that inlet is ignored. Use a filterdesign dictionary's filter coefficients The word dictionary, followed by a symbol that references a named filterdesign object dictionary (set via the name attribute), will cause the biquad~ object to use the dictionary values for filter coefficients. Clear the biquad~ object's memory Clears the biquad~ object's memory of previous inputs and outputs, resetting xn-1, xn-2, yn-1, and yn-2 to 0. Function depends on inlet In left inlet: Signal to be filtered. The filter mixes the current input sample with the two previous input samples and the two previous output samples according to the formula:

yn = a0xn + a1xn-1 + a2xn-2 - b1yn-1 - b2yn-2.

In 2nd inlet: Amplitude coefficient a0, for scaling the amount of the current input to be passed directly to the output.

In 3rd inlet: Amplitude coefficient a1, for scaling the amount of the previous input sample to be added to the output.

In 4th inlet: Amplitude coefficient a2, for scaling the amount of input sample n-2 to be added to the output.

In 5th inlet: Amplitude coefficient b1, for scaling the amount of the previous output sample to be added to the current output.

In right inlet: Amplitude coefficient b2, for scaling the amount of output sample n-2 to be added to the current output. . Preload filter coefficients The word stoke, followed by a list that specifies a set of filter coefficient values, will preload the filter so that it starts in a given initial state, allowing the filter to be used for purposes such as a ringing oscillator. Filter coefficient smoothing toggle Toggles the smoothing of filter coeffient changes. The filtered signal.