COAT - Cross-site Oldenburg-Aachener transfer-functions

This dataset describes individual head related transfer-functions (HRTFs) as well as headphone transfer-functions (HpTFs) measured at two different sites: 

Institute of Technical Acoustics (ITA), RWTH Aachen,52056 Aachen, Germany, (Now: Institute for Hearing Technology and Acoustics)

Medizinische Physik & Cluster of Excellence Hearing4All, Universität Oldenburg, 26111 Oldenburg, Germany

As used in the publications:

[1] Kohnen, M., Denk, F., Llorca-Bofi, J., Kollmeier, B., & Vorländer, M. (2021). Cross-site investigation on head-related and headphone transfer functions: variabilities in relation to loudness balancing. Acta Acustica, 5, 58.

https://doi.org/10.1051/aacus/2021051

[2] Denk, F., Kohnen, M., Llorca-Bofí, J., Vorländer, M., & Kollmeier, B. (2021). The “Missing 6 dB” Revisited: Influence of Room Acoustics and Binaural Parameters on the Loudness Mismatch Between Headphones and Loudspeakers. Frontiers in Psychology, 12.

https://doi.org/10.3389/fpsyg.2021.623670

Files are stored in the SOFA format, see www.sofaconventions.org for more information or the AES standard AES69-2015.

Participants:

14 participants were measured at both sites:

'ITA1' 'ITA2' 'ITA3' 'ITA4' 'ITA5' 'ITA6' 'ITA7'

'HM08CO04' 'ER06PH18' 'GA03EJ14' 'EL08RD06' 'MI08LF31' 'ER07ED05' 'EK06AS04'

Further 13 participants were measured at one site only:

Aachen:

'ITA01' 'ITA03' 'ITA06-08' 'ITA11-15' 'ITA17-19'

Oldenburg:

'AU05RD24' 'CH09US24' 'EN07NS03' 'ER03ED10' 'ER03IM11' 'ER04UT30' 'ER05EN06' 'ER09US30' 'IN04ER21' 'NE06RG13' 'NK07ER02' 'OF05UD28' 'SZ08CH09'

Position of the microphones:

ECEbl: Ear-canal entrance blocked, MEMS microphone with PIRATE plug (https://doi.org/10.5281/zenodo.2574395)

ED: Measurements close to the ear drum using probe tube microphones (ETYMOTICS ER-7C). The microphone itself is positioned outside the ear canal, leaving the ear canal open.

KEMAR ED: Measurements done with a KEMAR 45BB-12 using low-noise ear simulators and anthropometric ears.

KEMAR ECEbl: Measurements done with a KEMAR 45BB-12 using MEMS microphone as described above in 'ECEbl'.

HTX ED: GRAS headphone test fixture 45CA-9 with high-resolution ear simulator, HpTF only

Further information can be found in the files.

HpTFs [PA/V]:

The measurements were repeated eight times. Highly significant (and obviously faulty) measurement were erased, thus, some files contain fewer than eight repetitions.

Headphones used (identifier in Aachen (ITA) follow a continuous numeration while in Oldenburg the identifier is used in combination with the headphone type):

At each site one sample of Beyerdynamic DT770 Pro 250 Ohm ( ITA01 | OL1 )

At each site two samples of Sennheiser HD650 ( ITA02, ITA03 | OL1, OL2 )

At each site two samples of ETYMOTICS ER-4PT earplugs ( ITA02, ITA03 | OL1, OL2 )

The recordings were equalized for the microphone, shifted in time to a common digital delay of 10 ms (441 samples at 44100 Hz) and windowed to a duration of about 93 ms (4096 samples at 44100 Hz). The resulting unit is Pa/V.

Further information can be found in the files.

HpTF measurements at the blocked ear canal of 'MI08LF31' using the HD650 in Aachen was sorted out due to faulty results and is therefore missing.

HRTFs [dB re free-field]:

Site-exclusive HRTFs (ITA followed by two digits) in Aachen contain only a frontal direction. Subjects were seated 2.25m in front of a Genelec 8030C in a hemi-anechoic chamber with absorbers on the floor between the subjects and the loudspeaker.

ITA Aachen: Participants standing on a rotating table in front of a 64-loudspeaker arc (1.2m radius) in a hemi-anechoic room, see Richter, J. (2019) https://doi.org/10.30819/4906. Loudspeaker used were Tang Band W1-2025SA.

Oldenburg: Participants seated, legs covered with absorbers in a fixed 87 loudspeaker set-up in a full anechoic chamber, see Denk et Al. (2018) https://doi.org/10.1177/2331216518779313. Loudspeaker used were Genelec 8030C.

Measurements were divided by the free-field response of the microphones in a regularized manner. Afterwards the data was extrapolated towards lower frequencies and windowed to a length of about 8 ms (356 samples at 44100Hz) and 93 ms (4096 samples) for Aachen external participants.

For 'ITA03' the probe-tube measurements are missing in Aachen.

Further information can be found in the files.