aes 143 convention e-brief: 357 a database of head-related ... · itd (s) 20 elevation, (deg.)...

A database of head-related transfer function (HRTF) and morphological measurements

Rahulram Sridhar, Joseph G. Tylka, and Edgar Y. Choueiri

3D Audio and Applied Acoustics Laboratory, Princeton University

AES 143 Convention e-Brief: 357

Website: www.princeton.edu/3D3AThis work was sponsored in part by the Sony Corporation of America and approved by the Institutional Review Board at Princeton University

2 .2 Measurement Setup1 IntroductionAn individual’s HRTFs describe the idiosyncratic filtering of incident sound waves by the individual's morphology. HRTFs are widely used to synthesize binaural signals for spatial audio reproduction, and are generally acquired either through acoustical measurements [1] or by modeling from morphological data [2, for example].Acoustically measured HRTFs:• are accurate but difficult to acquire,• serve as benchmarks for validating modeled HRTFs,• and serve as training data for developing HRTF models.Publicly available databases provide measured HRTFs for many human subjects and mannequins [3]. However, few such databases also include corresponding morphological data. Here, we describe an ongoing project to measure HRTFs and corresponding 3D morphological scans of subjects, which we provide as a freely available database.

MORPHOLOGICAL SCANS

4 Data Visualization

Reference-grade

Consumer-grade

B&K HATS 4128C

-80080

-400

50

0

360

ITD

(s)

20Elevation, (deg.)

400

270-10

800

180-40Azimuth, (deg.)90-70 0

Human subject3 Data Processing

MORPHOLOGICAL SCANSImport

head and torso scanswith and without wig cap

Import

pinnae scans

2 .1 Measurement Details

HRTFsMeasurement room Anechoic chamber

Number of directions 648 (72 azimuths × 9 elevations)Loudspeakers 9 × Genelec 8010A

Binaural microphones Theoretica Applied Physics BACCH-BM Pro

Excitation signal

Multiple exponential sine sweeps [1]Duration: 500 ms (200 ms inter-sweep delay)Nominal frequency range: 20 Hz to 48 kHz

Sampling rate: 96 kHz

Data export format SOFA [3]

Morphological ScansHead and torso scanner PrimeSense Carmine 1.09

Pinna scanner Artec Space SpiderScanning software Skanect Pro; Artec Studio 12 ProData export format PLY

Turntable

0.76 m

45o

-57o

Circular arc with loudspeakers

Headrest

Drum-throne seat

Outline ET250-3D turntable

HRTFs

HRTFs

Invert

f (kHz)

�

10�3

0

0.05 0.1 30 32

with regularization [4]

ExportHRIRs, RIRs and BIRs, in SOFA

✻

Convolve

Importreference impulse responses (RIRs)

Importbinaural impulse responses (BIRs)

Window10 ms Tukey

5 Summary

References[1] Majdak, P., Balazs, P., and Laback, B., J. Audio Eng. Soc., 55(7/8), pp. 623–637, 2007. [2] Sridhar, R. and Choueiri, E. Y., in Audio Eng. Soc. Convention 143, 2017. [3] https://www.sofaconventions.org/mediawiki/index.php/Files [4] Farina, A., in Audio Eng. Soc. Convention 122, 2007.

We have begun an on-going project to measure HRTFs and 3D scans of the head and upper torso of humans and mannequins, and compile the data into a freely available database which may be downloaded from: http://www.princeton.edu/3D3A/HRTFMeasurements.html

↣ Merge

Exportconsumer-grade

scan in PLY

Aligny-axis = interaural axis

y

x

z

q

f

interaural

axis

0.5-0.7 m

wig capalignment marker

PrimeSense Carmine 1.09

Artec Space Spider

0.2-0.3 m

Exportreference-grade

scan in PLY