HoaOrder | SuperCollider 3.13.0 Help

Source: HoaOrder.sc

Description

Higher Order Ambisonic (HOA) component indexing, coefficients and performance, by order.

Class Methods

HoaOrder.new(order)

Create a new instance.

Arguments:

order

Ambisonic order.

Instance Methods

.lm

Return an array of Associated Legendre degrees (ℓ) and indices (m).

.l

Return an array of Associated Legendre degrees (ℓ).

.m

Return an array of Associated Legendre indices (m).

.indices(ordering: 'acn', subset: 'all')

Return Higher Order Ambisonic (HOA) indices.

Arguments:

ordering

Component ordering scheme:

`\acn`	Ambisonic Channel Number (ACN)
`\sid`	Single Index Designation (SID)
`\fuma`	Furse-Malham (FuMa)

subset

`\all`	All indices
`\zonal`	Zonal
`\sectoral`	Sectoral
`\tesseral`	Tesseral
`\rotate`	Rotation around z-axis, aka yaw

.size

Return number of ambisonic components.

.sph(theta: 0, phi: 0)

Return N3D normalized angular encoding coefficients.

Arguments:

theta	Azimuth, in radians.
phi	Elevation, in radians.

.normalisation(scheme: 'n3d')

Return component normalisation coefficients.

Arguments:

scheme

Component normalisation schemes:

`\n3d`	Orthonormal basis for 3D decomposition (N3D)
`\sn3d`	Semi-normalised basis for 3D decomposition (SN3D)
`\n2d`	Orthonormal basis for 2D decomposition (N2D)
`\sn2d`	Semi-normalised basis for 2D decomposition (SN2D)
`\maxN`	Maximum normalisation (maxN)
`\MaxN`	Gerzon / Furse-Malham (MaxN)
`\fuma`	Synonym for MaxN (FuMa)

.reflection(mirror: 'reflect')

Return component reflection coefficients.

Arguments:

mirror

`\reflect`	Mirror across the origin. Equivalent to: `\flip * \flop * \flap`.
`\flip`	Mirror in the y-axis.
`\flop`	Mirror in the x-axis.
`\flap`	Mirror in the z-axis.
`\CondonShortleyPhase`	Condon-Shortley Phase. Equivalent to: `\flip * \flop`.
`\origin`	Synonym for `\reflect`.
`\x`	Synonym for `\flop`.
`\y`	Synonym for `\flip`.
`\z`	Synonym for `\flap`.

.radiusAtFreq(freq, speedOfSound)

Return the effective decoding radius, in meters.

Arguments:

freq	Frequency, in Hz.
speedOfSound	Speed of sound, in meters per second.

.freqAtRadius(radius, speedOfSound)

Return the effective decoding frequency, in Hz.

Arguments:

radius	Radius, in meters.
speedOfSound	Speed of sound, in meters per second.

.proxWeights(freq, radius, speedOfSound)

Return complex near-field effect proximity radial filtering coefficients, collected by Associated Legendre degree (ℓ).

Arguments:

freq	Frequency, in Hz.
radius	Radius, in meters.
speedOfSound	Speed of sound, in meters per second.

.distWeights(freq, radius, speedOfSound)

Return complex near-field effect distance radial filtering coefficients, collected by Associated Legendre degree (ℓ).

Arguments:

freq	Frequency, in Hz.
radius	Radius, in meters.
speedOfSound	Speed of sound, in meters per second.

.ctrlWeights(freq, encRadius, decRadius, speedOfSound)

Return complex near-field effect control radial filtering coefficients, collected by Associated Legendre degree (ℓ).

Arguments:

freq	Frequency, in Hz.
encRadius	Encoding radius, in meters.
decRadius	Decoding radius, in meters.
speedOfSound	Speed of sound, in meters per second.

.foclWeights(freq, radius, window: 'reg', speedOfSound)

Return real near-field effect focalisation radial filtering coefficients, collected by Associated Legendre degree (ℓ).

Arguments:

freq

Frequency, in Hz.

radius

Radius, in meters.

window

Angular weighting window.

`\reg`	Regularised¹
`\hp`	(Butterworth) High Pass²
`\cos`	Cosine³
`\sin`	Sine⁴

speedOfSound

Speed of sound, in meters per second.

Beaming & Decoder matching

Three standard beam shapes are offered:

keyword	beam shape	localisation vector	virtual microphone
`\basic`	strict soundfield	maximum velocity rV	Hyper-cardioid
`\energy`	energy optimised	maximum energy rE	Super-cardioid
`\controlled`	controlled opposites	minimum diametric energy	Cardioid

.beamWeights(beamShape: 'basic', dim: 3)

Return beamforming coefficients, collected by Associated Legendre degree (ℓ).

Arguments:

beamShape	Keyword argument for beam shape. See above.
dim	The number of dimensions: 2D or 3D.

.matchWeight(beamShape: 'basic', dim: 3, match: 'amp', numChans)

Return matching weight for an ambisonic decoder.

Arguments:

beamShape

Keyword argument for beam shape. See above.

dim

The number of dimensions: 2D or 3D.

match

Matching criteria:

`\amp`	pressure (loudspeaker sum)
`\rms`	spherical harmonic energy
`\energy`	loudspeaker energy

numChans

Number of loudspeakers.

NOTE: Must be set when choosing match: \energy.

.spreadE(beamShape: 'basic', dim: 3)

Return the half angle of the maximum average energy spread for an ambisonic decoder.

Arguments:

beamShape	Keyword argument for beam shape. See above.
dim	The number of dimensions: 2D or 3D.

Returns:

An IdentityDictionary of values:

`\cos`	roll-off to ~-3dB, in radians
`\hvc`	roll-off to ~-6dB, in radians

.meanE(beamShape: 'basic', dim: 3)

Return reduced energy for an ambisonic decoder.

Arguments:

beamShape	Keyword argument for beam shape. See above.
dim	The number of dimensions: 2D or 3D.

.rV(beamShape: 'basic', dim: 3)

Return maximum average magnitude of the velocity localisation vector (rV) for an ambisonic decoder.

Arguments:

beamShape	Keyword argument for beam shape. See above.
dim	The number of dimensions: 2D or 3D.

.rE(beamShape: 'basic', dim: 3)

Return maximum average magnitude of the energy localisation vector (rE) for an ambisonic decoder.

Arguments:

beamShape	Keyword argument for beam shape. See above.
dim	The number of dimensions: 2D or 3D.

[1] - S. Favrot and J. Buchholz. 2010. “Impact of Regularization of near Field Coding Filters for 2D and 3D Higher-Order Ambisonics on Auditory Distance Cues.” in Proc. of the 2nd International Symposium on Ambisonics and Spherical Acoustics. Paris.

[2] - J. Daniel. 2003. “Spatial sound encoding including near field effect: Introducing distance coding filters and a viable, new ambisonic format,” in Proc. of the 23rd International Conference of the Audio Engineering Society.

[3] - J. Ahrens and S. Spors. 2009. “Spatial encoding and decoding of focused virtual sound sources,” in Proc. of the 1st Ambisonics Symposium. Paris.

[4] - A sine function variation of the window proposed by Ahrens & Spors.

helpfile source: /home/stefan/.local/share/SuperCollider/downloaded-quarks/atk-sc3/HelpSource/Classes/HoaOrder.schelp
link::Classes/HoaOrder::

HoaOrder : Object Extension

HoaOrder.new(order)

Arguments:

.order

.lm

.l

.m

.indices(ordering: 'acn', subset: 'all')

Arguments:

.size

.sph(theta: 0, phi: 0)

Arguments:

.normalisation(scheme: 'n3d')

Arguments:

.reflection(mirror: 'reflect')

Arguments:

.radiusAtFreq(freq, speedOfSound)

Arguments:

.freqAtRadius(radius, speedOfSound)

Arguments:

.proxWeights(freq, radius, speedOfSound)

Arguments:

.distWeights(freq, radius, speedOfSound)

Arguments:

.ctrlWeights(freq, encRadius, decRadius, speedOfSound)

Arguments:

.foclWeights(freq, radius, window: 'reg', speedOfSound)

Arguments:

.beamWeights(beamShape: 'basic', dim: 3)

Arguments:

.matchWeight(beamShape: 'basic', dim: 3, match: 'amp', numChans)

Arguments:

.spreadE(beamShape: 'basic', dim: 3)

Arguments:

Returns:

.meanE(beamShape: 'basic', dim: 3)

Arguments:

.rV(beamShape: 'basic', dim: 3)

Arguments:

.rE(beamShape: 'basic', dim: 3)

Arguments:

HoaOrder : Object
Extension