==Description==

This conventions essentially defines the setup used to measure HRTFs in free field. The measured HRTFs are represented as FIR filters, with a single HRTF set of a listener per file.

[[File:SimpleFreeFieldHRIR-0.3.png|right|thumb|225px]]
This convention set essentially defines the setup used in the [http://www.kfs.oeaw.ac.at/hrtf ARI], LISTEN, FIU, CIPIC, and other similar HRTF databases. The measurements are done in free field with a single excitation source assuming an omnidirectional loudspeaker. Human listeners are considered and thus, the number of receivers is usually two. Note that usually, only the apparent azimuth and elevation angles are provided and this information is modeled as the variation of the source position. This convention set can, however, also be used to describe more complex data where the tilt of the head is varied or the listener is not exactly in the center of the measurement setup. The measured HRTFs are represented as FIR filters, with a single HRTF set of a listener per file.

* General attributes: SOFAConventions: SimpleFreeFieldHRIR, Datatype: FIR, RoomType: free field, other general attributes...

* Listener: The listener is in the origin of the setup, facing in the direction of the y-axis. Thus, for default values, ListenerPosition=[0 0 0], ListenerView=[1 0 0], ListenerUp=[0 0 1], all given in cartesian coordinates.
* Receivers: Per default, two Receivers (=ears) are defined on a head with radius H (in meter, default: 0.09), thus, ReceiverPosition=[0 H 0; 0 -H 0]. Note that any positive integer number of Receivers can be used, though.
* Source: Source consists of a single Emitter only. Per default, EmitterPosition=[0 0 0] in cartesian coordinates. SourcePosition (in spherical coordinates!) varies corresponding to the different azimuth and elevation angles of the measurement directions. Per default, SourcePosition=[0 0 1] (azimuth 0°, elevation 0°, distance 1 m). SourceUp and SourceView are not considered and optional.

In SimpleFreeFieldHRIR version 0.2, we used ListenerRotation to describe the different measurement directions, and the source was assumed to be in the center of the measurement setup. This, however, limited the use of SimpleFreeFieldHRIR, thus, in version 0.4, we use SourcePosition to represent the different HRTF directions. By doing so, more complex data can be described where the tilt of the head is varied, or the listener is not exactly in the center of the measurement setup.

In SimpleFreeFieldHRIR version 0.4, the last version before AES69-2015, we adapted the conventions to SOFA 0.6. The most striking changes are:
* ''Source'' has been renamed to '''Origin''' (in order to reduce the confusion with the object source)
* ''SubjectID'' has been renamed to '''ListenerShortName''' (in order to be more consistent with the general naming of the metadata).

== Version 1.2 ==

SimpleFreeFieldHRIR version 1.2 will represent the standardized convention set from AES69-2025.

As compared to version 1.1, version 1.2 defines the optional metadata Normalization.

{| border="1"
!Name
!Default
![[SOFA_conventions#AnchorFlags|Flags]]
![[SOFA_conventions#AnchorDimensions|Dimensions]]
!Type
!Comment
|-
|GLOBAL:Conventions||<nowiki>SOFA</nowiki>||rm||||attribute||
|-
|GLOBAL:Version||<nowiki>2.1</nowiki>||rm||||attribute||
|-
|GLOBAL:SOFAConventions||<nowiki>SimpleFreeFieldHRIR</nowiki>||rm||||attribute||This convention set is for impulse responses recorded under free-field conditions or conditions with irrelevant room information.
|-
|GLOBAL:SOFAConventionsVersion||<nowiki>1.2</nowiki>||rm||||attribute||
|-
|GLOBAL:APIName||<nowiki></nowiki>||rm||||attribute||
|-
|GLOBAL:APIVersion||<nowiki></nowiki>||rm||||attribute||
|-
|GLOBAL:ApplicationName||<nowiki></nowiki>||||||attribute||
|-
|GLOBAL:ApplicationVersion||<nowiki></nowiki>||||||attribute||
|-
|GLOBAL:AuthorContact||<nowiki></nowiki>||m||||attribute||
|-
|GLOBAL:Comment||<nowiki></nowiki>||||||attribute||
|-
|GLOBAL:DataType||<nowiki>FIR</nowiki>||rm||||attribute||
|-
|GLOBAL:History||<nowiki></nowiki>||||||attribute||
|-
|GLOBAL:License||<nowiki>No license provided, ask the author for permission</nowiki>||m||||attribute||
|-
|GLOBAL:DatabaseName||<nowiki></nowiki>||m||||attribute||Unique name of the database to which these data belong.
|-
|GLOBAL:ListenerShortName||<nowiki></nowiki>||m||||attribute||ID of the subject from the database.
|-
|GLOBAL:Organization||<nowiki></nowiki>||m||||attribute||
|-
|GLOBAL:References||<nowiki></nowiki>||||||attribute||
|-
|GLOBAL:RoomType||<nowiki>free field</nowiki>||m||||attribute||
|-
|GLOBAL:Origin||<nowiki></nowiki>||||||attribute||
|-
|GLOBAL:DateCreated||<nowiki></nowiki>||m||||attribute||
|-
|GLOBAL:DateModified||<nowiki></nowiki>||m||||attribute||
|-
|GLOBAL:Title||<nowiki></nowiki>||m||||attribute||
|-
|ListenerPosition||<nowiki>[0 0 0] </nowiki>||m||IC, MC||double||
|-
|ListenerPosition:Type||<nowiki>cartesian</nowiki>||m||||attribute||
|-
|ListenerPosition:Units||<nowiki>metre</nowiki>||m||||attribute||
|-
|ReceiverPosition||<nowiki>[0 0.09 0; 0 -0.09 0]</nowiki>||m||RCI||double||
|-
|ReceiverPosition:Type||<nowiki>cartesian</nowiki>||m||||attribute||
|-
|ReceiverPosition:Units||<nowiki>metre</nowiki>||m||||attribute||
|-
|SourcePosition||<nowiki>[0 0 1]</nowiki>||m||IC, MC||double||The source position is assumed to vary around the listener.
|-
|SourcePosition:Type||<nowiki>spherical</nowiki>||m||||attribute||
|-
|SourcePosition:Units||<nowiki>degree, degree, metre</nowiki>||m||||attribute||
|-
|EmitterPosition||<nowiki>[0 0 0]</nowiki>||m||eCI, eCM||double||Source consists of a single Emitter only.
|-
|EmitterPosition:Type||<nowiki>cartesian</nowiki>||m||||attribute||
|-
|EmitterPosition:Units||<nowiki>metre</nowiki>||m||||attribute||
|-
|ListenerUp||<nowiki>[0 0 1]</nowiki>||m||IC, MC||double||
|-
|ListenerView||<nowiki>[1 0 0]</nowiki>||m||IC, MC||double||
|-
|ListenerView:Type||<nowiki>cartesian</nowiki>||m||||attribute||
|-
|ListenerView:Units||<nowiki>metre</nowiki>||m||||attribute||
|-
|Data.IR||<nowiki>[0 0]</nowiki>||m||mrn||double||
|-
|Data.SamplingRate||<nowiki>48000</nowiki>||m||I, M||double||Sampling rate of the samples in Data.IR and Data.Delay.
|-
|Data.SamplingRate:Units||<nowiki>hertz</nowiki>||m||||attribute||Unit of the sampling rate.
|-
|Data.Delay||<nowiki>[0 0]</nowiki>||m||IR, MR||double||Additional delay of each IR (in samples, with the time interval as described by SamplingRate).
|-
|SourceUp||<nowiki>[0 0 1]</nowiki>||||IC, MC||double||
|-
|SourceView||<nowiki>[1 0 0]</nowiki>||||IC, MC||double||
|-
|SourceView:Type||<nowiki>cartesian</nowiki>||||||attribute||
|-
|SourceView:Units||<nowiki>metre</nowiki>||||||attribute||
|-
|Normalization||<nowiki>0</nowiki>||||I||double||Describing normalization status.
|-
|Normalization:Description||<nowiki></nowiki>||||||attribute||Narrative explanation of the normalization.
|-
|Normalization:References||<nowiki></nowiki>||||||attribute||References to publications describing the normalization.
|-
|Normalization:URI||<nowiki></nowiki>||||||attribute||URIs or DOIs to publications describing the normalization.
|}

== Version 1.1 ==

SimpleFreeFieldHRIR version 1.1 represents a development stage towards standardized convention set from AES69-2025.

As compared to version 1.0, version 1.1 updates the datatype such that the size of dimension R is defined by the corresponding size of Data.IR.

{| border="1"
!Name
!Default
![[SOFA_conventions#AnchorFlags|Flags]]
![[SOFA_conventions#AnchorDimensions|Dimensions]]
!Type
!Comment
|-
|GLOBAL:Conventions||<nowiki>SOFA</nowiki>||rm||||attribute||
|-
|GLOBAL:Version||<nowiki>2.1</nowiki>||rm||||attribute||
|-
|GLOBAL:SOFAConventions||<nowiki>SimpleFreeFieldHRIR</nowiki>||rm||||attribute||This convention set is for impulse responses recorded under free-field conditions or conditions with irrelevant room information.
|-
|GLOBAL:SOFAConventionsVersion||<nowiki>1.1</nowiki>||rm||||attribute||
|-
|GLOBAL:APIName||<nowiki></nowiki>||rm||||attribute||
|-
|GLOBAL:APIVersion||<nowiki></nowiki>||rm||||attribute||
|-
|GLOBAL:ApplicationName||<nowiki></nowiki>||||||attribute||
|-
|GLOBAL:ApplicationVersion||<nowiki></nowiki>||||||attribute||
|-
|GLOBAL:AuthorContact||<nowiki></nowiki>||m||||attribute||
|-
|GLOBAL:Comment||<nowiki></nowiki>||||||attribute||
|-
|GLOBAL:DataType||<nowiki>FIR</nowiki>||rm||||attribute||
|-
|GLOBAL:History||<nowiki></nowiki>||||||attribute||
|-
|GLOBAL:License||<nowiki>No license provided, ask the author for permission</nowiki>||m||||attribute||
|-
|GLOBAL:DatabaseName||<nowiki></nowiki>||m||||attribute||Unique name of the database to which these data belong.
|-
|GLOBAL:ListenerShortName||<nowiki></nowiki>||m||||attribute||ID of the subject from the database.
|-
|GLOBAL:Organization||<nowiki></nowiki>||m||||attribute||
|-
|GLOBAL:References||<nowiki></nowiki>||||||attribute||
|-
|GLOBAL:RoomType||<nowiki>free field</nowiki>||m||||attribute||
|-
|GLOBAL:Origin||<nowiki></nowiki>||||||attribute||
|-
|GLOBAL:DateCreated||<nowiki></nowiki>||m||||attribute||
|-
|GLOBAL:DateModified||<nowiki></nowiki>||m||||attribute||
|-
|GLOBAL:Title||<nowiki></nowiki>||m||||attribute||
|-
|ListenerPosition||<nowiki>[0 0 0] </nowiki>||m||IC, MC||double||
|-
|ListenerPosition:Type||<nowiki>cartesian</nowiki>||m||||attribute||
|-
|ListenerPosition:Units||<nowiki>metre</nowiki>||m||||attribute||
|-
|ReceiverPosition||<nowiki>[0 0.09 0; 0 -0.09 0]</nowiki>||m||RCI, RCM||double||
|-
|ReceiverPosition:Type||<nowiki>cartesian</nowiki>||m||||attribute||
|-
|ReceiverPosition:Units||<nowiki>metre</nowiki>||m||||attribute||
|-
|SourcePosition||<nowiki>[0 0 1]</nowiki>||m||IC, MC||double||The source position is assumed to vary around the listener.
|-
|SourcePosition:Type||<nowiki>spherical</nowiki>||m||||attribute||
|-
|SourcePosition:Units||<nowiki>degree, degree, metre</nowiki>||m||||attribute||
|-
|EmitterPosition||<nowiki>[0 0 0]</nowiki>||m||eCI, eCM||double||Source consists of a single Emitter only.
|-
|EmitterPosition:Type||<nowiki>cartesian</nowiki>||m||||attribute||
|-
|EmitterPosition:Units||<nowiki>metre</nowiki>||m||||attribute||
|-
|ListenerUp||<nowiki>[0 0 1]</nowiki>||m||IC, MC||double||
|-
|ListenerView||<nowiki>[1 0 0]</nowiki>||m||IC, MC||double||
|-
|ListenerView:Type||<nowiki>cartesian</nowiki>||m||||attribute||
|-
|ListenerView:Units||<nowiki>metre</nowiki>||m||||attribute||
|-
|Data.IR||<nowiki>[0 0]</nowiki>||m||mrn||double||
|-
|Data.SamplingRate||<nowiki>48000</nowiki>||m||I, M||double||Sampling rate of the samples in Data.IR and Data.Delay.
|-
|Data.SamplingRate:Units||<nowiki>hertz</nowiki>||m||||attribute||Unit of the sampling rate.
|-
|Data.Delay||<nowiki>[0 0]</nowiki>||m||IR, MR||double||Additional delay of each IR (in samples, with the time interval as described by SamplingRate).
|-
|SourceUp||<nowiki>[0 0 1]</nowiki>||||IC, MC||double||
|-
|SourceView||<nowiki>[1 0 0]</nowiki>||||IC, MC||double||
|-
|SourceView:Type||<nowiki>cartesian</nowiki>||||||attribute||
|-
|SourceView:Units||<nowiki>metre</nowiki>||||||attribute||
|}

== Version 1.0 ==

SimpleFreeFieldHRIR version 1.0 represents the current standardized convention set from AES69-2015.

{| border="1"
!Name
!Default
![[SOFA_conventions#AnchorFlags|Flags]]
![[SOFA_conventions#AnchorDimensions|Dimensions]]
!Type
!Comment
|-
|GLOBAL:Conventions||<nowiki>SOFA</nowiki>||rm||||attribute||
|-
|GLOBAL:Version||<nowiki>2.1</nowiki>||rm||||attribute||
|-
|GLOBAL:SOFAConventions||<nowiki>SimpleFreeFieldHRIR</nowiki>||rm||||attribute||This convention set is for HRIRs recorded under free-field conditions or other IRs created under conditions where room information is irrelevant
|-
|GLOBAL:SOFAConventionsVersion||<nowiki>1.0</nowiki>||rm||||attribute||
|-
|GLOBAL:APIName||<nowiki></nowiki>||rm||||attribute||
|-
|GLOBAL:APIVersion||<nowiki></nowiki>||rm||||attribute||
|-
|GLOBAL:ApplicationName||<nowiki></nowiki>||||||attribute||
|-
|GLOBAL:ApplicationVersion||<nowiki></nowiki>||||||attribute||
|-
|GLOBAL:AuthorContact||<nowiki></nowiki>||m||||attribute||
|-
|GLOBAL:Comment||<nowiki></nowiki>||||||attribute||
|-
|GLOBAL:DataType||<nowiki>FIR</nowiki>||rm||||attribute||
|-
|GLOBAL:History||<nowiki></nowiki>||||||attribute||
|-
|GLOBAL:License||<nowiki>No license provided, ask the author for permission</nowiki>||m||||attribute||
|-
|GLOBAL:Organization||<nowiki></nowiki>||m||||attribute||
|-
|GLOBAL:References||<nowiki></nowiki>||||||attribute||
|-
|GLOBAL:RoomType||<nowiki>free field</nowiki>||m||||attribute||
|-
|GLOBAL:Origin||<nowiki></nowiki>||||||attribute||
|-
|GLOBAL:DateCreated||<nowiki></nowiki>||m||||attribute||
|-
|GLOBAL:DateModified||<nowiki></nowiki>||m||||attribute||
|-
|GLOBAL:Title||<nowiki></nowiki>||m||||attribute||
|-
|ListenerPosition||<nowiki>[0 0 0] </nowiki>||m||IC, MC||double||
|-
|ListenerPosition:Type||<nowiki>cartesian</nowiki>||m||||attribute||
|-
|ListenerPosition:Units||<nowiki>metre</nowiki>||m||||attribute||
|-
|ReceiverPosition||<nowiki>[0 0.09 0; 0 -0.09 0]</nowiki>||m||rCI, rCM||double||
|-
|ReceiverPosition:Type||<nowiki>cartesian</nowiki>||m||||attribute||
|-
|ReceiverPosition:Units||<nowiki>metre</nowiki>||m||||attribute||
|-
|SourcePosition||<nowiki>[0 0 1]</nowiki>||m||IC, MC||double||Source position is assumed to vary for different directions/positions around the listener
|-
|SourcePosition:Type||<nowiki>spherical</nowiki>||m||||attribute||
|-
|SourcePosition:Units||<nowiki>degree, degree, metre</nowiki>||m||||attribute||
|-
|EmitterPosition||<nowiki>[0 0 0]</nowiki>||m||eCI, eCM||double||
|-
|EmitterPosition:Type||<nowiki>cartesian</nowiki>||m||||attribute||
|-
|EmitterPosition:Units||<nowiki>metre</nowiki>||m||||attribute||
|-
|GLOBAL:DatabaseName||<nowiki></nowiki>||m||||attribute||name of the database to which these data belong
|-
|GLOBAL:ListenerShortName||<nowiki></nowiki>||m||||attribute||ID of the subject from the database
|-
|ListenerUp||<nowiki>[0 0 1]</nowiki>||m||IC, MC||double||
|-
|ListenerView||<nowiki>[1 0 0]</nowiki>||m||IC, MC||double||
|-
|ListenerView:Type||<nowiki>cartesian</nowiki>||m||||attribute||
|-
|ListenerView:Units||<nowiki>metre</nowiki>||m||||attribute||
|-
|Data.IR||<nowiki>[0 0]</nowiki>||m||mRn||double||
|-
|Data.SamplingRate||<nowiki>48000</nowiki>||m||I, M||double||
|-
|Data.SamplingRate:Units||<nowiki>hertz</nowiki>||m||||attribute||
|-
|Data.Delay||<nowiki>[0 0]</nowiki>||m||IR, MR||double||
|-
|SourceUp||<nowiki>[0 0 1]</nowiki>||||IC, MC||double||
|-
|SourceView||<nowiki>[1 0 0]</nowiki>||||IC, MC||double||
|-
|SourceView:Type||<nowiki>cartesian</nowiki>||||||attribute||
|-
|SourceView:Units||<nowiki>metre</nowiki>||||||attribute||
|}

== Old, deprecated versions ==

For historical reasons the older versions of the SimpleFreeFieldHRIR Convention are listed below.

=== Version 0.4 (deprecated) ===

[[File:SimpleFreeFieldHRIR-0.3.png|right|thumb|225px]]
This conventions essentially defines the setup used in the [http://www.kfs.oeaw.ac.at/hrtf ARI], LISTEN, FIU, CIPIC, and other similar HRTF databases. The measurements are done in free field with a single excitation source assuming an omnidirectional loudspeaker. Human listeners are considered and thus, the number of receivers is two. Note that usually, only the apparent azimuth and elevation angles are provided and this information is modeled as the variation of the source position. This conventions can, however, also be used to describe more complex data where the tilt of the head is varied or the listener is not exactly in the center of the measurement setup. The measured HRTFs are represented as FIR filters, with a single HRTF set of a listener per file.

* General attributes: SOFAConventions: SimpleFreeFieldHRIR, Datatype: FIR, RoomType: free field, other general attributes...

* Listener: The listener is in the origin of the setup, facing in the direction of the y-axis. Thus, for default values, ListenerPosition=[0 0 0], ListenerView=[1 0 0], ListenerUp=[0 0 1], all given in cartesian coordinates.
* Receivers: Two receivers (=ears) on a head with radius H (in meter, default: 0.09): ReceiverPosition=[0 -H 0; 0 +H 0].
* Source: Source consists of a single emitter. For default values, EmitterPosition=[0 0 0] in cartesian coordinates. SourcePosition (in spherical coordinates!) varies corresponding to the different azimuth and elevation angles of the measurement directions. For default, SourcePosition=[0 0 1] (azimuth 0°, elevation 0°, distance 1 m). SourceUp and SourceView are not considered and optional.

{| border="1"
!Name
!Default
!Flags
!Dimensions
!Type
!Comment
|-
|GLOBAL:Conventions||SOFA||rm||||attribute||
|-
|GLOBAL:Version||0.6||rm||||attribute||
|-
|GLOBAL:SOFAConventions||SimpleFreeFieldHRIR||rm||||attribute||This convention set is for HRIRs recorded under free-field conditions or other IRs created under conditions where room information is irrelevant
|-
|GLOBAL:SOFAConventionsVersion||0.4||rm||||attribute||
|-
|GLOBAL:APIName||||rm||||attribute||
|-
|GLOBAL:APIVersion||||rm||||attribute||
|-
|GLOBAL:ApplicationName||||||||attribute||
|-
|GLOBAL:ApplicationVersion||||||||attribute||
|-
|GLOBAL:AuthorContact||||m||||attribute||
|-
|GLOBAL:Comment||||||||attribute||
|-
|GLOBAL:DataType||FIR||rm||||attribute||
|-
|GLOBAL:History||||||||attribute||
|-
|GLOBAL:License||No license provided, ask the author for permission||m||||attribute||
|-
|GLOBAL:Organization||||m||||attribute||
|-
|GLOBAL:References||||||||attribute||
|-
|GLOBAL:RoomType||free field||m||||attribute||
|-
|GLOBAL:Origin||||||||attribute||
|-
|GLOBAL:DateCreated||||m||||attribute||
|-
|GLOBAL:DateModified||||m||||attribute||
|-
|GLOBAL:Title||||m||||attribute||
|-
|ListenerPosition||[0 0 0] ||m||IC, MC||double||
|-
|ListenerPosition:Type||cartesian||m||||attribute||
|-
|ListenerPosition:Units||meter||m||||attribute||
|-
|ReceiverPosition||[0 -0.09 0; 0 0.09 0]||m||rCI, rCM||double||
|-
|ReceiverPosition:Type||cartesian||m||||attribute||
|-
|ReceiverPosition:Units||meter||m||||attribute||
|-
|SourcePosition||[0 0 1]||m||IC, MC||double||Source position is assumed to vary for different directions/positions around the listener
|-
|SourcePosition:Type||spherical||m||||attribute||
|-
|SourcePosition:Units||degree, degree, meter||m||||attribute||
|-
|EmitterPosition||[0 0 0]||m||eCI, eCM||double||
|-
|EmitterPosition:Type||cartesian||m||||attribute||
|-
|EmitterPosition:Units||meter||m||||attribute||
|-
|GLOBAL:DatabaseName||||m||||attribute||name of the database to which these data belong
|-
|GLOBAL:ListenerShortName||||m||||attribute||ID of the subject from the database
|-
|ListenerUp||[0 0 1]||m||IC, MC||double||
|-
|ListenerView||[1 0 0]||m||IC, MC||double||
|-
|ListenerView:Type||cartesian||m||||attribute||
|-
|ListenerView:Units||meter||m||||attribute||
|-
|Data.IR||[1 1]||m||mRn||double||
|-
|Data.SamplingRate||48000||m||I||double||
|-
|Data.SamplingRate:Units||hertz||m||||attribute||
|-
|Data.Delay||[0 0]||m||IR, MR||double||
|}

=== Proposed for version 0.3 (deprecated) ===

[[File:SimpleFreeFieldHRIR-0.3.png|right|thumb|225px]]
This conventions essentially defines the setup used in the [http://www.kfs.oeaw.ac.at/hrtf ARI], LISTEN, FIU, CIPIC, and other similar HRTF databases. The measurements are done in free field with a single excitation source assuming an omnidirectional loudspeaker. Human listeners are considered and thus, the number of receivers is two. Note that usually, only the apparent azimuth and elevation angles are provided and this information is modeled as the variation of the source position. This conventions can, however, also be used to describe more complex data where the tilt of the head is varied or the listener is not exactly in the center of the measurement setup. The measured HRTFs are represented as FIR filters, with a single HRTF set of a listener per file.

* General attributes: SOFAConventions: SimpleFreeFieldHRIR, Datatype: FIR, RoomType: free field, other general attributes...

* Listener: The listener is in the origin of the setup, facing in the direction of the y-axis. Thus, for default values, ListenerPosition=[0 0 0], ListenerView=[1 0 0], ListenerUp=[0 0 1], all given in cartesian coordinates.
* Receivers: Two receivers (=ears) on a head with radius H (in meter, default: 0.09): ReceiverPosition=[0 -H 0; 0 +H 0].
* Source: Source consists of a single emitter. For default values, EmitterPosition=[0 0 0] in cartesian coordinates. SourcePosition (in spherical coordinates!) varies corresponding to the different azimuth and elevation angles of the measurement directions. For default, SourcePosition=[0 0 1] (azimuth 0°, elevation 0°, distance 1 m). SourceUp, SourceView, and SourceRotation are not considered and optional.

{| border="1"
!Name
!Default
!Flags
!Dimensions
!Type
!Comment
|-
|GLOBAL:Conventions||SOFA||rm||||attribute||
|-
|GLOBAL:Version||0.5||rm||||attribute||
|-
|GLOBAL:SOFAConventions||SimpleFreeFieldHRIR||rm||||attribute||This conventions is for HRIRs recorded under free-field conditions or other IRs created under conditions where room information is irrelevant
|-
|GLOBAL:SOFAConventionsVersion||0.3||rm||||attribute||
|-
|GLOBAL:APIName||||rm||||attribute||
|-
|GLOBAL:APIVersion||||rm||||attribute||
|-
|GLOBAL:ApplicationName||||m||||attribute||
|-
|GLOBAL:ApplicationVersion||||m||||attribute||
|-
|GLOBAL:AuthorContact||||m||||attribute||
|-
|GLOBAL:Comment||||m||||attribute||
|-
|GLOBAL:DataType||FIR||rm||||attribute||
|-
|GLOBAL:History||||m||||attribute||
|-
|GLOBAL:License||No license provided, ask the author for permission||m||||attribute||
|-
|GLOBAL:Organization||||m||||attribute||
|-
|GLOBAL:References||||m||||attribute||
|-
|GLOBAL:RoomType||free field||m||||attribute||
|-
|GLOBAL:Source||||m||||attribute||
|-
|GLOBAL:TimeCreated||||m||||attribute||
|-
|GLOBAL:TimeModified||||m||||attribute||
|-
|GLOBAL:Title||||m||||attribute||
|-
|ListenerPosition||[0 0 0] ||m||IC, MC||double||
|-
|ListenerPosition:Type||cartesian||m||||attribute||
|-
|ListenerPosition:Units||meter||m||||attribute||
|-
|ReceiverPosition||[0 -0.09 0; 0 0.09 0]||m||rCI, rCM||double||
|-
|ReceiverPosition:Type||cartesian||m||||attribute||
|-
|ReceiverPosition:Units||meter||m||||attribute||
|-
|SourcePosition||[0 0 1]||m||IC, MC||double||Source position is assumed to vary for different directions/positions around the listener
|-
|SourcePosition:Type||spherical||m||||attribute||
|-
|SourcePosition:Units||degree, degree, meter||m||||attribute||
|-
|EmitterPosition||[0 0 0]||m||eCI, eCM||double||
|-
|EmitterPosition:Type||cartesian||m||||attribute||
|-
|EmitterPosition:Units||meter||m||||attribute||
|-
|GLOBAL:DatabaseName||||m||||attribute||name of the database to which these data belong
|-
|GLOBAL:SubjectID||||m||||attribute||ID of the subject from the database
|-
|ListenerUp||[0 0 1]||m||IC, MC||double||
|-
|ListenerView||[1 0 0]||m||IC, MC||double||
|-
|Data.IR||[1 1]||m||mRn||double||
|-
|Data.SamplingRate||48000||m||I||double||
|-
|Data.SamplingRate:Units||hertz||m||||attribute||
|-
|Data.Delay||[0 0]||m||IR, MR||double||
|}

=== Version 0.2 (deprecated) ===

[[File:SimpleFreeFieldHRIR-0.2.png|right|thumb|225px]]
This conventions essentially defines the setup used in the [http://www.kfs.oeaw.ac.at/hrtf ARI], LISTEN, FIU, CIPIC, and other similar HRTF databases. The measurements are done in free field with a single excitation source assuming an omnidirectional loudspeaker. Human listeners are considered and thus, the number of receivers is two. Azimuth and elevation angles are varied and the tilt of the head is not considered during the measurement. The measured HRTFs are represented as FIR filters, with a single HRTF set of a listener per file.

* General attributes: SOFAConventions: SimpleFreeFieldHRIR, Datatype: FIR, RoomType: free field, other general attributes...
* Source: Source is in the origin of the setup and consists of a single emitter. For default values, SourcePosition: (0 0 0), and EmitterPosition: (0 0 0). SourceUp, SourceView, and SourceRotation are not considered and optional.
* Listener: The listener is in the measurement distance X (in meter) from the source, facing the source. For default values, we consider a single distance X, thus, ListenerPosition: (X 0 0), ListenerView: (0 0 0), ListenerUp: (X 0 1).
* Receivers: Two receivers (=ears) on a head with radius H (in meter): ReceiverPosition: (0 -H 0; 0 +H 0).
* The different azimuth and elevation angles of the measurement are described by the ListenerRotation as [M 3] matrix (in degrees). The coordinate type is [http://en.wikipedia.org/wiki/Axes_conventions DIN 9300].

{| border="1"
!Name
!Default
!Flags
!Dimensions
!Type
!Comment
|-
|GLOBAL_Conventions||SOFA||rm||||||
|-
|GLOBAL_Version||0.4||rm||||||
|-
|GLOBAL_SOFAConventions||SimpleFreeFieldHRIR||rm||||||
|-
|GLOBAL_SOFAConventionsVersion||0.2||rm||||||
|-
|GLOBAL_APIName||||rm||||||Insert the API Name here
|-
|GLOBAL_APIVersion||||rm||||||Insert the API Version here
|-
|GLOBAL_AuthorContact||||m||||||
|-
|GLOBAL_License||No license provided, ask the author for permission||m||||||
|-
|GLOBAL_Organization||||m||||||
|-
|GLOBAL_RoomType||free field||m||||||
|-
|GLOBAL_DataType||FIR||rm||||||
|-
|GLOBAL_History||||m||||||
|-
|GLOBAL_Source||||m||||||
|-
|GLOBAL_Title||||m||||||
|-
|GLOBAL_References||||m||||||
|-
|GLOBAL_Comment||||m||||||
|-
|GLOBAL_TimeCreated||||m||||||will be updated when saving and not existing or empty
|-
|GLOBAL_TimeModified||||m||||||will be updated each time when saving
|-
|GLOBAL_ApplicationName||||m||||||
|-
|GLOBAL_ApplicationVersion||||m||||||
|-
|GLOBAL_DatabaseName||||m||||||
|-
|GLOBAL_SubjectID||||m||||||
|-
|ListenerPosition||[1 0 0] ||m||IC, MC||double||
|-
|ListenerPosition_Type||cartesian||m||||||
|-
|ListenerPosition_Units||meter||m||||||
|-
|ListenerUp||[0 0 1]||m||IC, MC||double||
|-
|ListenerView||[-1 0 0]||m||IC, MC||double||
|-
|ListenerRotation||[0 0 0]||m||IC, MC||double||
|-
|ListenerRotation_Type||din9300||m||||||
|-
|ListenerRotation_Units||degrees||m||||||
|-
|ReceiverPosition||[0 -0.09 0; 0 0.09 0]||m||rCI, rCM||double||
|-
|ReceiverPosition_Type||cartesian||m||||||
|-
|ReceiverPosition_Units||meter||m||||||
|-
|SourcePosition||[0 0 0]||m||IC, MC||double||
|-
|SourcePosition_Type||cartesian||m||||||
|-
|SourcePosition_Units||meter||m||||||
|-
|EmitterPosition||[0 0 0]||m||eCI, eCM||double||
|-
|EmitterPosition_Type||cartesian||m||||||
|-
|EmitterPosition_Units||meter||m||||||
|-
|Data.IR||[1 1]||m||mRn||double||
|-
|Data.SamplingRate||48000||m||I||double||
|-
|Data.SamplingRate_Units||hertz||m||||||
|-
|Data.Delay||[0 0]||m||IR, MR||double||
|}

=== Version 0.1 (deprecated) ===
{| border="1"
!Name
!Default
!Flags
!Dimensions
!Comment
|-
|GLOBAL_Conventions||SOFA||rm|| ||
|-
|GLOBAL_Version||0.3||rm|| ||
|-
|GLOBAL_SOFAConventions||SimpleFreeFieldHRIR||rm ||||
|-
|GLOBAL_SOFAConventionsVersion||0.1||m|| ||
|-
|GLOBAL_APIName||*||rm|| ||Insert the API Name here
|-
|GLOBAL_APIVersion||*||rm || ||Insert the API Version here
|-
|GLOBAL_ApplicationName||||m ||||
|-
|GLOBAL_ApplicationVersion||||m ||||
|-
|GLOBAL_AuthorContact||||m ||||
|-
|GLOBAL_License||No license provided, ask the author for permission||m||||
|-
|GLOBAL_Organization||||m ||||
|-
|GLOBAL_DatabaseName||||m||||
|-
|GLOBAL_SubjectID||||m ||||
|-
|GLOBAL_RoomType||free field||m||||
|-
|GLOBAL_DataType||FIR||m||||
|-
|GLOBAL_History||||||||
|-
|GLOBAL_Comment||||||||
|-
|GLOBAL_DatabaseTimeCreated||*||m|||| will be updated when saving and not existing or empty
|-
|GLOBAL_DatabaseTimeModified||*||m ||||will be updated each time when saving
|-
|I||1||rm||I||
|-
|I_LongName||singleton dimension||rm|| ||
|-
|R||2||rm||R||
|-
|R_LongName||number of receivers||rm||||
|-
|E||1||rm||E||
|-
|E_LongName||number of emitters||rm||||
|-
|N|| - ||m||N||
|-
|N_LongName||time||m|| ||
|-
|N_Units||samples||m|| ||
|-
|M|| - ||m||M||
|-
|M_LongName||number of measurements||rm ||||
|-
|C||3||rm||C||
|-
|C_LongName||coordinate triplet||rm||||
|-
|ListenerPosition|| [1 0 0] ||m||IC, MC||
|-
|ListenerPosition_Type||cartesian||m|| ||
|-
|ListenerPosition_Unitsmeter||||m||||
|-
|ListenerUp||[1.2 0 1]||m||IC, MC||
|-
|ListenerUp_Type||cartesian||m||||
|-
|ListenerUp_Units||meter||m||||
|-
|ListenerView||[0 0 0]||m||IC, MC||
|-
|ListenerView_Type||cartesian||m||||
|-
|ListenerView_Units||meter||m||||
|-
|ListenerRotation||[0 0 0]||m||IC, MC||
|-
|-
|ListenerRotation_Type||din9300||m||||
|-
|ListenerRotation_Units||degrees||m ||||
|-
|ReceiverPosition||[0 -0.09 0; 0 0.09 0]||m||rCI, rCM||
|-
|ReceiverPosition_Type||cartesian||m||||
|-
|ReceiverPosition_Units||meter||m ||||
|-
|SourcePosition||[0 0 0]||m||IC, MC||
|-
|SourcePosition_Type||cartesian||m||||
|-
|SourcePosition_Units||meter||m ||||
|-
|SourceUp||[0 0 1]||m||IC, MC||
|-
|SourceUp_Type||cartesian||m||||
|-
|SourceUp_Units||meter||m||||
|-
|SourceView||[1 0 0]||m||IC, MC||
|-
|SourceView_Type||cartesian||m||||
|-
|SourceView_Units||meter||m||||
|-
|EmitterPosition||[0 0 0]||m||eCI, eCM||
|-
|EmitterPosition_Type||cartesian||m||||
|-
|EmitterPosition_Units||meter||m ||||
|-
|Data.IR||[1 1]||m||mRn||
|-
|Data.SamplingRate||48000||m||I||
|-
|Data.SamplingRate_Units||hertz||m||||
|}

MediaWiki:Sidebar

2025-09-29T06:40:35Z

Isfmiho:

MediaWiki:Sidebar

2025-09-29T06:36:30Z

2025-09-24T11:59:35Z

Isfmiho: /* Version 1.1 */

Isfmiho:

* '''[https://www.oeaw.ac.at/en/ari/team/our-team/majdak-piotr Piotr Majdak]''' ([https://www.oeaw.ac.at/en/ari/ Acoustics Research Institute], [http://www.oeaw.ac.at/ Austrian Academy of Sciences]): project leader, Matlab support
* '''[https://www.noisternig.com/ Markus Noisternig]''' ([http://www.ircam.fr/ UMR STMS IRCAM-CNRS-UPMC]): specifications, standardization
* '''[https://www.qu.tu-berlin.de/menue/team/alumni/hagen_wierstorf/ Hagen Wierstorf]''' ([https://www.qu.tu-berlin.de/menue/qu/ Quality and Usability Lab], [http://www.tu-berlin.de/ Technical University of Berlin]): Octave support
* '''[https://www.oeaw.ac.at/en/ari/team/our-team/mihocic-michael Michael Mihocic]''' ([https://www.oeaw.ac.at/en/ari/ Acoustics Research Institute], [http://www.oeaw.ac.at/ Austrian Academy of Sciences]): Website support, Matlab support
* '''Harald Ziegelwanger''' ([https://www.oeaw.ac.at/en/ari/ Acoustics Research Institute], [http://www.oeaw.ac.at/ Austrian Academy of Sciences]): specifications
* '''Thibaut Carpentier''' ([http://www.ircam.fr/ UMR STMS IRCAM-CNRS-UPMC]): C++ API, specifications

SOFA was initiated in January 2012 during the 4th AABBA meeting in Berlin (Blauert, 2009). Since then, many other researches helped by providing feedback and support:

* '''Matthieu Parmentier''' ([http://www.francetelevisions.fr/ France Television]): initiation of the [http://www.aes.org/ AES] standardization
* '''Wolfgang Hrauda''' ([http://iem.at Institute for Electronic Music and Acoustics], [http://www.kug.ac.at University of Arts and Music], Graz)
* '''Bruce Olson, AESSC Chair''': [http://www.aes.org/ AES] standardization committee chair
* '''Mark Yonge, AESSC Secretary''': [http://www.aes.org/ AES] standardization committee secretary
* '''Rozenn Nicol''' ([http://laborange.fr/ Orange Labs, France Telecom])
* '''[http://steinhardt.nyu.edu/faculty_bios/view/Agnieszka_Roginska Agnieszka Roginska]''' ([http://steinhardt.nyu.edu/ Music Technology, New York University])
* '''[http://www.ais.riec.tohoku.ac.jp/Member/yoh/ Yôiti Suzuki]''' ([http://www.riec.tohoku.ac.jp/index-e.shtml Research Institute of Electrical Communication, Tohoku University])
* '''Kanji Watanabe''' ([http://www.akita-pu.ac.jp/language/EN/ Faculty of Engineering, Akita Prefectural University])
* '''Yukio Iwaya''' (Faculty of Engineering, Tohoku Gakuin University)
* '''Michele Geronazzo''' (University of Padova): headphone support

Also many thanks go to the '''[http://www.aes.org/ AES] standardization team''' for their support.

== Contact ==

If you have questions about SOFA, please send an email to the [mailto:sofacoustics-devel@lists.sourceforge.net mailing list]. You need to be a member of the mailing list to send a message to the list. You don't need to be a member to send an email to the moderator.

Also you are invited to contact the standardization committee of X212. Join us at [http://www.aes.org/standards/development/membership.cfm] and select "SC-02-08-E" from the list.

== References ==
Blauert, J., Braasch, J., Bucholz, J., Colburn, H.S., Jekosch, U., Kohlrausch, A., Mourjopoulos, J., Pulkki, V., Raake, A. (2009) "Aural assessment by means of binaural algorithms - The AABBA project" in proceedings of the International Symposium on Auditory and Audiological Research (ISSAR), Helsingør, Denmark.

GeneralFIR-E

2025-07-17T09:30:36Z

Isfmiho:

This conventions defines a general convention with FIR-E as DataType (no restrictions but DataType).

GeneralFIR-E is the standardized version of the previously proposed [[GeneralFIR]] convention. It extends GeneralFIR by having Emitter as an explicit dimension in the data.

The conventions is defined in AES69-2022 (SOFA 2.1).

{| border="1"
!Name
!Default
![[SOFA_conventions#AnchorFlags|Flags]]
![[SOFA_conventions#AnchorDimensions|Dimensions]]
!Type
!Comment
|-
|GLOBAL:Conventions||<nowiki>SOFA</nowiki>||rm||||attribute||
|-
|GLOBAL:Version||<nowiki>2.1</nowiki>||rm||||attribute||
|-
|GLOBAL:SOFAConventions||<nowiki>GeneralFIR-E</nowiki>||rm||||attribute||This conventions stores IRs for general purposes, i.e., only the SOFA general metadata are predefined.
|-
|GLOBAL:SOFAConventionsVersion||<nowiki>2.0</nowiki>||rm||||attribute||
|-
|GLOBAL:APIName||<nowiki></nowiki>||rm||||attribute||
|-
|GLOBAL:APIVersion||<nowiki></nowiki>||rm||||attribute||
|-
|GLOBAL:ApplicationName||<nowiki></nowiki>||||||attribute||
|-
|GLOBAL:ApplicationVersion||<nowiki></nowiki>||||||attribute||
|-
|GLOBAL:AuthorContact||<nowiki></nowiki>||m||||attribute||
|-
|GLOBAL:Comment||<nowiki></nowiki>||||||attribute||
|-
|GLOBAL:DataType||<nowiki>FIR-E</nowiki>||rm||||attribute||We use FIR datatype which in addition depends on Emitters (E).
|-
|GLOBAL:History||<nowiki></nowiki>||||||attribute||
|-
|GLOBAL:License||<nowiki>No license provided, ask the author for permission</nowiki>||m||||attribute||
|-
|GLOBAL:Organization||<nowiki></nowiki>||m||||attribute||
|-
|GLOBAL:References||<nowiki></nowiki>||||||attribute||
|-
|GLOBAL:RoomType||<nowiki>free field</nowiki>||m||||attribute||It can be free field, reverberant, shoebox or dae.
|-
|GLOBAL:Origin||<nowiki></nowiki>||||||attribute||
|-
|GLOBAL:DateCreated||<nowiki></nowiki>||m||||attribute||
|-
|GLOBAL:DateModified||<nowiki></nowiki>||m||||attribute||
|-
|GLOBAL:Title||<nowiki></nowiki>||m||||attribute||
|-
|ListenerPosition||<nowiki>[0 0 0] </nowiki>||m||IC, MC||double||
|-
|ListenerPosition:Type||<nowiki>cartesian</nowiki>||m||||attribute||
|-
|ListenerPosition:Units||<nowiki>metre</nowiki>||m||||attribute||
|-
|ReceiverPosition||<nowiki>[0 0 0]</nowiki>||m||ICI, RCI, RCM||double||
|-
|ReceiverPosition:Type||<nowiki>cartesian</nowiki>||m||||attribute||
|-
|ReceiverPosition:Units||<nowiki>metre</nowiki>||m||||attribute||
|-
|SourcePosition||<nowiki>[0 0 0]</nowiki>||m||IC, MC||double||
|-
|SourcePosition:Type||<nowiki>cartesian</nowiki>||m||||attribute||
|-
|SourcePosition:Units||<nowiki>metre</nowiki>||m||||attribute||
|-
|EmitterPosition||<nowiki>[0 0 0]</nowiki>||m||ICI, ECI, ECM||double||Each speaker is represented as an Emitter.
|-
|EmitterPosition:Type||<nowiki>cartesian</nowiki>||m||||attribute||
|-
|EmitterPosition:Units||<nowiki>metre</nowiki>||m||||attribute||
|-
|Data.IR||<nowiki>0</nowiki>||m||mrne||double||Impulse responses.
|-
|Data.SamplingRate||<nowiki>48000</nowiki>||m||I, M||double||Sampling rate of the samples in Data.IR and Data.Delay.
|-
|Data.SamplingRate:Units||<nowiki>hertz</nowiki>||m||||attribute||Unit of the sampling rate.
|-
|Data.Delay||<nowiki>0</nowiki>||m||IRI, MRI, MRE||double||Additional delay of each IR (in samples, with the time interval as described by SamplingRate).
|}