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atk-sc3/Classes (extension) | Libraries > Ambisonic Toolkit > Coefficients & Theory

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Higher Order Ambisonic (HOA) radial utilities

Description

Higher Order Ambisonic (HOA) radial utilities. Useful for finding ambisonic decoder effective radius, effective order and effective frequency.

Class Methods

.new

Create a new instance, in terms of spatial frequency.

Arguments:

waveNumber

Angular wavenumber, in radians per meter.

.newFreq

Create a new instance, in terms of frequency by the relationship:

2pi * freq / speedOfSound.

Arguments:

freq

Frequency, in Hz.

speedOfSound

Speed of sound, in meters per second. Def: AtkHoa.speedOfSound

.newWn

Create a new instance, in terms of normalized frequency wn by the relationship:

pi * wn * sampleRate / speedOfSound.

Arguments:

wn

Normalized frequency. DC = 0.0, Nyquist = 1.0;

sampleRate

Sample rate, in Hz.

speedOfSound

Speed of sound, in meters per second. Def: AtkHoa.speedOfSound

.newRadius

Create a new instance, in terms of distance and effective order by the relationship:

order / radius.

Arguments:

radius

Radius, in meters. Def: AtkHoa.refRadius

order

Ambisonic order. Def: AtkHoa.defaultOrder

.newDelay

Create a new instance, in terms of time and effective order by the relationship:

order / (delay * speedOfSound).

Arguments:

delay

Radial delay, in seconds.

order

Ambisonic order. Def: AtkHoa.defaultOrder

speedOfSound

Speed of sound, in meters per second. Def: AtkHoa.speedOfSound

Instance Methods

Radius & delay

.radius

Return effective radius, in meters.

Arguments:

order

Ambisonic order. Def: AtkHoa.defaultOrder

.delay

Return effective delay, in seconds.

Arguments:

order

Ambisonic order. Def: AtkHoa.defaultOrder

speedOfSound

Speed of sound, in meters per second. Def: AtkHoa.speedOfSound

Effective order

.orderAtRadius

Return effective ambisonic order, given radius.

Arguments:

radius

Radius, in meters. Def: AtkHoa.refRadius

.orderAtDelay

Return effective ambisonic order, given delay.

Arguments:

delay

Delay, in seconds.

speedOfSound

Speed of sound, in meters per second. Def: AtkHoa.speedOfSound

Frequency

.freq

Return frequency, in Hz.

Arguments:

speedOfSound

Speed of sound, in meters per second. Def: AtkHoa.speedOfSound

.wn

Return normalized frequency. DC = 0.0, Nyquist = 1.0.

Arguments:

sampleRate

Sample rate, in Hz.

speedOfSound

Speed of sound, in meters per second. Def: AtkHoa.speedOfSound

.waveNumber

Angular wavenumber, in radians per meter.

NFE

.proxWeights

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

Arguments:

radius

Radius, in meters. Def: AtkHoa.refRadius

order

Ambisonic order. Def: AtkHoa.defaultOrder

Discussion:

These complex weights represent the magnitude and phase change of each degree when encoding an otherwise far-field source at a distance of radius.

See further discussion on The Near-Field Effect (NFE).

.distWeights

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

Arguments:

radius

Radius, in meters. Def: AtkHoa.refRadius

order

Ambisonic order. Def: AtkHoa.defaultOrder

Discussion:

These complex weights are the reciprocal of -proxWeights.

See further discussion on The Near-Field Effect (NFE).

.ctrlWeights

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

Arguments:

encRadius

Encoding radius, in meters. Def: AtkHoa.refRadius

decRadius

Decoding radius, in meters. Def: AtkHoa.refRadius

order

Ambisonic order. Def: AtkHoa.defaultOrder

Discussion:

These complex weights represent a ratio of the -proxWeights of the encoding radius to the decoding radius, i.e. proxWeights(encRadius) / proxWeights(decRadius).

See further discussion on The Near-Field Effect (NFE).

Examples

Effective radius

Effective order

Effective frequency