The Pd Spectral Toolkit facilitates frequency domain signal processing with a family of spectral transformation, calculation, and data manipulation objects. These objects implement low-level algorithms that simplify patches by handling the complex math and data manipulation commonly required for spectral signal processing.

The toolkit was created by Cooper Baker in 2013, with generous support from a University of California San Diego research grant supervised by Tom Erbe. In 2019 the project was updated as a cross-platform library and added to Pd's external object management system. Special thanks to Miller Puckette for invaluable insight regarding spectral math and the Pd api.

Baker, C., Erbe, T. "Pd Spectral Toolkit", Proceedings of the International Computer Music Conference, Pp. 410-413, Perth, Australia, 2013.

· Pd-Spectral-Toolkit.zip
· Source Code Browser
· GitHub Repository
· ICMC Paper.pdf
· Poster.pdf

Pd Assisted Install:

· Pd -> Help -> Find Externals -> "Pd Spectral Toolkit" -> Search
· Select the appropriate version for your system

Manual Install:

· Copy the Pd Spectral Toolkit folder into your Pd installation (i.e. /Library/Pd/Pd Spectral Toolkit in Mac OS)
· Edit Pd startup settings to load pd_spectral_toolkit
· Restart Pd

comparison

!&&~ !=~ !||~ &&~ <=~ <~ ==~ >=~ >~ ||~

operator

!~ %~ cmplxabs~ cmplxadd~ cmplxdiv~ cmplxmult~ cmplxsqrt~ cmplxsub~ recip~ rounder~ trunc~

conversion

amptodb~ amptomag~ cartoamp~ cartodb~ cartofreq~ cartomag~ cartophase~ cartopolar~ ctltosig~ dbtoamp~ dbtomag~ degtorad~ degtoturn~ freqtocar~ freqtophase~ freqtopolar~ magtoamp~ magtodb~ phasetofreq~ polartocar~ polartofreq~ radtodeg~ radtoturn~ sigtoctl~ turntodeg~ turntorad~

spectral

binindex~ binmax~ binmin~ binmix~ binmonitor~ binsort~ bintrim~ blocksmooth~ freqsieve~ fundfreq~ harmprod~ magtrim~ oscbank~ pafft~ paifft~ partconv~ peaks~ phaseaccum~ phasedelta~ piwrap~ rotate~ valleys~ windower winfft~ winifft~

misc

bitsafe~ countwrap dspbang~ monitor~ rgbtable scale~ softclip~ tabindex~ terminal

!&&~	logical not and
!=~	logical not equal
!||~	logical not or
!~	not
&&~	logical and
%~	modulo
<=~	logical less than or equal
<~	logical less than
==~	logical equal
>=~	logical greater than or equal
>~	logical greater than
||~	logical or
amptodb~	amplitude to dB-FS decibels conversion
amptomag~	amplitude to magnitude conversion
binindex~	outputs a ramp with values from zero to block size minus one
binmax~	reports maximum bin value and associated data per block
binmin~	reports minimum bin value and associated data per block
binmix~	mixes inlet 2 values for all matching inlet 1 values and zeroes all others
binmonitor~	outputs a float representing the value of a single bin
binsort~	sorts spectral data in ascending or descending order
bintrim~	zeroes bin values outside of a specified range
bitsafe~	fixes infinity and not a number values
blocksmooth~	replaces a block's zero values with preceeding adjacent non-zero values
cartoamp~	cartesian coordinates to amplitude conversion
cartodb~	cartesian coordinates to dB-FS decibels conversion
cartofreq~	cartesian coordinates to magnitude and frequency pairs conversion
cartomag~	cartesian coordinates to magnitude conversion
cartophase~	cartesian coordinates to phase conversion
cartopolar~	cartesian coordinates to polar coordinates conversion
cmplxabs~	complex absolute value
cmplxadd~	complex addition
cmplxdiv~	complex division
cmplxmult~	complex multiplication
cmplxsqrt~	complex square root
cmplxsub~	complex subtraction
countwrap	bang driven wrapping counter
ctltosig~	control range to signal range conversion
dbtoamp~	dB-FS decibels to amplitude conversion
dbtomag~	dB-FS decibels to magnitude conversion
degtorad~	degrees to radians conversion
degtoturn~	degrees to turns conversion
dspbang~	outputs a bang when dsp is turned on
freqsieve~	assigns frequencies and magnitudes to proper bins
freqtocar~	magnitude and frequency pairs to cartesian coordinates conversion
freqtophase~	frequency to phase conversion
freqtopolar~	magnitude and frequency pairs to polar coordinates conversion
fundfreq~	reports most prominent fundamental frequency per spectral block
harmprod~	harmonic product spectrum
magtoamp~	magnitude to amplitude conversion
magtodb~	magnitude to dB-FS decibels conversion
magtrim~	zeroes bin values outside of a specified magnitude range
monitor~	samples a signal and outputs a float every 20 milliseconds
oscbank~	oscillator bank for spectral resynthesis
pafft~	windowed phase aligned fast fourier transform
paifft~	windowed normalized phase aligned inverse fast fourier transform
partconv~	partitioned convolution with cartesian coordinates
peaks~	finds peaks in spectral data and zeroes everything else
phaseaccum~	running phase sums for each bin per frame
phasedelta~	phase deviation per frame for each bin
phasetofreq~	phase to frequency conversion
piwrap~	wraps a signal between -pi and pi
polartocar~	polar coordinates to cartesian coordinates conversion
polartofreq~	polar coordinates to magnitude and frequency pairs conversion
radtodeg~	radians to degrees conversion
radtoturn~	radians to turns conversion
recip~	reciprocal calculation
rgbtable	outputs color values based on input float value
rotate~	rotates samples in a signal vector
rounder~	rounds decimal values to specified precision
scale~	scales values from one range to another
sigtoctl~	signal range to control range conversion
softclip~	soft clipping waveshaper
tabindex~	writes table values at index location
terminal	command line shell interface
trunc~	truncates decimal values to specified precision
turntodeg~	turns to degrees conversion
turntorad~	turns to radians conversion
valleys~	finds valleys in spectral data and zeroes everything else
windower	writes various window functions into arrays
winfft~	windowed fast fourier transform
winifft~	windowed normalized inverse fast fourier transform

Performs a logical not and comparison of two signals and outputs 1 or 0. inlet 1: value a inlet 2: value b outlet: result argument: value b

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Performs a logical not equal comparison of two signals and outputs 1 or 0. inlet 1: value a inlet 2: value b outlet: result argument: value b

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Performs a logical not or comparison of two signals and outputs 1 or 0. inlet 1: value a inlet 2: value b outlet: result argument: value b

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Performs a logical not operation on a signal. inlet: value outlet: result

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Performs a logical and comparison of two signals and outputs 1 or 0. inlet 1: value a inlet 2: value b outlet: result argument: value b

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Performs a modulo operation using the values of two signals and outputs the result. inlet 1: dividend inlet 2: divisor outlet: remainder argument: divisor

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Performs a logical less than or equal comparison of two signals and outputs 1 or 0. inlet 1: value a inlet 2: value b outlet: result argument: value b

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Performs a logical less than comparison of two signals and outputs 1 or 0. inlet 1: value a inlet 2: value b outlet: result argument: value b

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Performs a logical equal comparison of two signals and outputs 1 or 0. inlet 1: value a inlet 2: value b outlet: result argument: value b

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Performs a logical greater than or equal comparison of two signals and outputs 1 or 0. inlet 1: value a inlet 2: value b outlet: result argument: value b

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Performs a logical greater than comparison of two signals and outputs 1 or 0. inlet 1: value a inlet 2: value b outlet: result argument: value b

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Performs a logical or comparison of two signals and outputs 1 or 0. inlet 1: value a inlet 2: value b outlet: result argument: value b

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Converts amplitude values to dB-FS decibel values. inlet: amplitude outlet: decibels

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Converts amplitude values to magnitude values. inlet 1: amplitude inlet 2: overlap factor outlet: magnitude argument: overlap factor

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Outputs ascending values from zero to block size minus one for each signal block. outlet: ascending sample indices

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Outputs the maximum sample value in block a, the associated sample value in block b, and the index location of samples a and b for each signal block. inlet 1: signal block a inlet 2: signal block b outlet 1: maximum a value outlet 2: associated b value outlet 3: index of a and b values

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Outputs the minimum sample value in block a, the associated sample value in block b, and the index location of samples a and b for each signal block. inlet 1: signal block a inlet 2: signal block b outlet 1: minimum a value outlet 2: associated b value outlet 3: index of a and b values

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Mixes inlet 2 values for all matching inlet 1 values. Mixed values are placed into location of largest inlet 2 value and all others are zeroed. Operates on one signal vector at a time. inlet 1: a values inlet 2: b values outlet 1: mixed a values outlet 2: mixed b values

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Outputs a float representing the value of a specific sample index in the signal vector once per block. Useful for looking at values of particular bins in spectral data. inlet 1: spectral data inlet 2: bin number outlet: bin value float argument: bin number

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Sorts Spectral data according to left inlet values and outputs the data in ascending or descending order. inlet 1: dataset a inlet 2: dataset b outlet 1: sorted dataset a outlet 2: dataset b sorted by a outlet 3: dataset indices sorted by a messages: "ascending" or "descending" arguments: "ascending" or "descending"

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Zeroes spectral data outside of a specified bin range. inlet 1: spectral data a inlet 2: spectral data b inlet 3: lower bin number inlet 4: upper bin number outlet 1: trimmed data a outlet 2: trimmed data b arguments: lower bin, upper bin

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Detects infinity or not a number values and replaces them with float or zero values. inlet: value outlet: result

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Replaces zero values within a signal vector with preceding adjacent non-zero values. inlet: rough signal outlet: smooth signal

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Converts cartesian coordinates to amplitude values. inlet 1: real value inlet 2: imaginary value inlet 3: overlap factor outlet: amplitude argument: overlap factor

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Converts cartesian coordinates to dB-FS decibel values. inlet 1: real value inlet 2: imaginary value inlet 3: overlap factor outlet: decibels argument: overlap factor

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Converts cartesian coordinates to magnitude and frequency pairs. inlet 1: real value inlet 2: imaginary value inlet 3: overlap factor outlet 1: magnitude outlet 2: frequency argument: overlap factor

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Converts cartesian coordinates to magnitude values. inlet 1: real value inlet 2: imaginary value outlet: magnitude

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Converts cartesian coordinates to phase values. inlet 1: real value inlet 2: imaginary value outlet: phase

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Converts cartesian coordinates to polar coordinates. inlet 1: real value inlet 2: imaginary value outlet 1: magnitude outlet 2: phase

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Calculates the absolute value of a complex number. inlet 1: real value inlet 2: imaginary value outlet: absolute value

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Adds two complex numbers and outputs the result. inlet 1: real value a inlet 2: imaginary value a inlet 3: real value b inlet 4: imaginary value b outlet 1: real sum outlet 2: imaginary sum argument 1: real value b argument 2: imaginary value b

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Performs complex division and outputs the result. inlet 1: real numerator inlet 2: imaginary numerator inlet 3: real denominator inlet 4: imaginary denominator outlet 1: real result outlet 2: imaginary result argument 1: real denominator argument 2: imaginary denominator

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Multiplies two complex numbers and outputs the result. inlet 1: real factor a inlet 2: imaginary factor a inlet 3: real factor b inlet 4: imaginary factor b outlet 1: real product outlet 2: imaginary product argument 1: real factor b argument 2: imaginary factor b

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Calculates the square root of a complex number and outputs the result. inlet 1: real value inlet 2: imaginary value outlet 1: real result outlet 2: imaginary result

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Subtracts one complex number form another and outputs the difference. inlet 1: real minuend inlet 2: imaginary minuend inlet 3: real subtrahend inlet 4: imaginary subtrahend outlet 1: real difference outlet 2: imaginary difference argument 1: real subtrahend argument 2: imaginary subtrahend

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Counts between minimum and maximum limits using an arbitrary increment value and wraps overflow back into counting range. inlet 1: bang inlet 2: current count inlet 3: increment value inlet 4: minimum value inlet 5: maximum value outlet: count value 1 argument: increment 2 arguments: minimum, maximum 3 arguments: increment, minimum, maximum 4 arguments: count, increment, minimum, maximum

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Scales values from control range (0 to 1) to signal range (-1 to 1). inlet: control values outlet: signal values

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Converts dB-FS decibel values to amplitude values. inlet: decibels outlet: amplitude

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Converts dB-FS decibel values to magnitude values. inlet 1: decibels inlet 2: overlap factor outlet: magnitude argument: overlap factor

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Converts degrees to radians. inlet: degrees outlet: radians

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Converts degrees to turns. inlet: degrees outlet: turns

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Outputs a bang when DSP is turned on or when the DSP chain is reconstructed. outlet: bang

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Assigns spectral frequency data to its proper bins based on frequency and magnitude. The frequency of greatest magnitude for each bin is selected and all other frequencies are ignored. An optional "unused" argument causes the object to output the ignored data. inlet 1: magnitude inlet 2: frequency inlet 3: overlap factor outlet 1: magnitude outlet 2: frequency 1 argument: "unused" or overlap factor 2 arguments: "unused" and overlap factor

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Converts magnitude and frequency pairs to cartesian coordinates. inlet 1: magnitude inlet 2: frequency inlet 3: overlap factor outlet 1: real values outlet 2: imaginary values argument: overlap factor

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Converts frequency values to phase values for each bin of spectral data. inlet 1: frequency inlet 2: overlap factor outlet: phase (-pi to pi) argument: overlap factor

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Converts magnitude and frequency pairs to polar coordinates. inlet 1: magnitude inlet 2: frequency inlet 3: overlap factor outlet 1: magnitude outlet 2: phase (-pi to pi) argument: overlap factor

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Finds the fundamental frequency of greatest magnitude within a specified frequency range. inlet 1: magnitude data inlet 2: phase data inlet 3: lower frequency limit inlet 4: upper frequency limit inlet 5: overlap factor outlet: frequency arguments: low freq, high freq, overlap factor

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Calculates the harmonic product spectrum of an input spectrum. Default harmonic product spectrum uses 4 harmonics (i.e. 4x downsampling) inlet: raw spectrum outlet: harmonic product spectrum argument: number of harmonics message: "set ___" (harmonics)

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Converts magnitude values to amplitude values. inlet 1: magnitude inlet 2: overlap factor outlet: amplitude argument: overlap factor

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Converts magnitude values to dB-FS decibel values. inlet 1: magnitude inlet 2: overlap factor outlet: decibels argument: overlap factor

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Zeroes spectral data outside of a specified magnitude range. inlet 1: spectral data a inlet 2: spectral data b inlet 3: lower magnitude value inlet 4: upper magnitude value outlet 1: trimmed data a outlet 2: trimmed data b arguments: lower magnitude, upper magnitude

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Samples a signal and outputs a float every 20 milliseconds. inlet: signal outlet: float

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Generates window-size/2 sinusoids based on input magnitude and frequency pairs. Magnitude and frequency changes are linearly interpolated between block boundaries. inlet 1: magnitude data inlet 2: frequency data inlet 3: overlap factor outlet: sinusoids

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Applies a window function then rotates the signal vector before performing a forward fast fourier transform. inlet 1: audio signal inlet 2: rotation amount in samples outlet 1: real values outlet 2: imaginary values argument: array_name (window array) message: "set array_name"

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Performs an inverse fast fourier transform then rotates the signal vector, applies a window function, and normalizes output. inlet 1: real values inlet 2: imaginary values inlet 3: rotation amount in samples outlet: audio signal argument: array_name (window array) message: "set array_name"

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Performs partitioned convolution using cartesian coordinates with a convolution kernel stored in an external array. inlet 1: real values inlet 2: imaginary values outlet 1: convolved real values outlet 2: convolved imaginary values message: "set kernel_array_name" argument: kernel_array_name

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Finds peaks in inlet 1 spectral data, outputs peak values and associated data from inlet 2. Optionally detects an arbitrary number of highest peaks. inlet 1: spectral data a inlet 2: spectral data b inlet 3: number of peaks outlet 1: data a peaks outlet 2: associated data b argument: number of peaks

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Calculates running sums of successive FFT frame phases for each bin. inlet: spectral phase data outlet: accumulated phase data

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Calculates phase deviation between successive FFT frames for each bin. inlet: spectral phase data outlet: phase delta data

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Converts phase values to frequency values for each bin of spectral data. inlet 1: frequency inlet 2: overlap factor outlet: phase (-pi to pi) argument: overlap factor

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Wraps a signal between -pi and pi. inlet 1: phase outlet: wrapped phase

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Converts polar coordinates to cartesian coordinates. inlet 1: magnitude inlet 2: phase outlet 1: real value outlet 2: imaginary value

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Converts polar coordinates to magnitude and frequency pairs. inlet 1: magnitude inlet 2: phase inlet 3: overlap factor outlet 1: magnitude outlet 2: frequency argument: overlap factor

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Converts radians to degrees. inlet: radians outlet: degrees

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Converts radians to turns. inlet: radians outlet: turns

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Calculates reciprocal values. inlet: signal outlet: reciprocal

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Outputs red, green, and blue values between 0 and 1 based on an input value between 0 and 1, according to the selected color scheme (default RGB). inlet 1: float outlet 1: red float outlet 2: green float outlet 3: blue float argument: color scheme message: color scheme

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Rotates a signal vector by an arbitrary number of samples. inlet 1: signal vector inlet 2: rotation amount outlet: rotated signal argument: rotation amount

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Rounds signal values to arbitrary precision of up to 8 decimal places. Default is zero decimal places. inlet 1: signal inlet 2: precision outlet: rounded signal argument: precision

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Scales a signal from one range to another. inlet 1: signal inlet 2: input minimum inlet 3: input maximum inlet 4: output minimum inlet 5: output maximum outlet: scaled signal arguments: in minimum, in maximum, out minimum, out maximum

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Scales values from signal range (-1 to 1) to control range (0 to 1). inlet: signal values outlet: control values

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Applies the polynomial waveshaping function: y[n] = ( 3x[n] / 2 ) - ( x[n]^3 / 2 ) inlet: signal outlet: smoothly clipped signal

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Writes signal values into a table at arbitrary locations and optionally clears the array at the start of each signal vector. inlet 1: signal inlet 2: sample index arguments: array_name, clear message: "clear x" (where x is 0 or 1; sets clear behavior) message: "set array_name" message: "bang" (redraws array)

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Sends messages to an instance of the operating system's command line shell and outputs the results. (mac/linux only) inlet: commands outlet: results

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Truncates signal values to arbitrary precision of up to 8 decimal places. Default is zero decimal places. inlet 1: signal inlet 2: precision outlet: truncated signal argument: precision

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Converts turns to degrees. inlet: turns outlet: degrees

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Converts turns to radians. inlet: turns outlet: radians

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Finds valleys in inlet 1 spectral data, outputs valley values and associated data from inlet 2. Optionally detects an arbitrary number of highest valleys. inlet 1: spectral data a inlet 2: spectral data b inlet 3: number of valleys outlet 1: data a valleys outlet 2: associated data b argument: number of valleys

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Writes normalized window functions into arrays. inlet: control messages arguments: array_name, window_type, parameter message: "set array_name" message: "window_type" message: "window_type parameter" window types: bartlett-hann, blackman, blackman-harris, blackman-nuttall, cosine, gaussian, hann, hanning, hann-poisson, hamming, kaiser, lanczos, nuttall, poisson, rectangle, sine, triangle, tukey parametric windows: blackman, gaussian, hann-poisson, kaiser, poisson, tukey

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Applies a window function then performs a fast fourier transform. inlet 1: audio signal outlet 1: real values outlet 2: imaginary values argument: array_name (window array) message: "set array_name"

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Performs an inverse fast fourier transform then applies a window function and normalizes output. inlet 1: real values inlet 2: imaginary values outlet: audio signal argument: array_name (window array) message: "set array_name"

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(c)(p)2024 Cooper Baker · All Rights Reserved · 8131 · 224428