SOFA specifications

Specifications

• SOFA 1.0 is reflected by the AES69-2015 standard. It mostly corresponds to SOFA 0.6, which specs can be downloaded here. A document with SOFA 1.0 specs is under preparation.

Older specs:

• Version 0.5: Download specifications
• Version 0.4: Discussion on the specifications (closed)
• Version 0.3: Download specifications
• Version 0.2: Specifications
• Version 0.1: Specifications as presented at the AES Convention 2013 in Rom

Data Types

FIR (SOFA 1.0)

For storing impulse responses.

Note: Delay is mandatory (set to 0 if not used).

Name	Default	Flags	Dimensions	Type	Comment
GLOBAL:DataType	FIR	rm		attribute
Data.IR	0	m	mRn	double	Impulse responses
Data.SamplingRate	48000	m	I	double	Sampling rate of the samples in Data.IR
Data.SamplingRate:Units	hertz	m		attribute	Unit of the sampling rate
Data.Delay	0	m	IR, MR	double	Additional delay of each IR (always in samples, i.e. units of N)

TF (SOFA 1.0)

Useful to describe a transfer function by a sparse number of frequencies. The guys from BEM simulations like it.

Note: the dimensional variable N is mandatory, it must be of dimension N, and must provide the frequency values.

Name	Default	Flags	Dimensions	Type	Comment
GLOBAL:DataType	TF	rm		attribute
Data.Real	0	m	mRn	double	The real part of the complex spectrum
Data.Imag	0	m	MRN	double	The imaginary part of the complex spectrum
N	0	m	N	double	Frequency values
N_LongName	frequency			attribute
N_Units	hertz	m		attribute	Unit of the values given in N

FIRE (proposed)

FIRE is based on FIR and is intended for storing impulse responses which depend on the emitter (E).

Note: Delay is mandatory (set to 0 if not used).

Name	Default	Flags	Dimensions	Type	Comment
GLOBAL:DataType	FIRE	rm		attribute
Data.IR	0	m	mREn	double	Impulse responses
Data.SamplingRate	48000	m	I	double	Sampling rate of the samples in Data.IR
Data.SamplingRate:Units	hertz	m		attribute	Unit of the sampling rate
Data.Delay	0	m	IRE, MRE	double	Additional delay of each IR (always in samples, i.e. units of N)

Coordinate system