Hi Junfeng,
in visual VR, „hyperstereo“ has been used in some settings with head-mounted displays. That means that the distance between the two virtual
cameras is set to a larger value than the interpupillary distance of the participant, so that binocular stereoscopic information is “exaggerated”.
Just a wild guess, but could you use a modified head geometry (e.g., a larger simulated head) when creating the BRIRs to make the relevant
cues more salient even at the low sampling rate?
Daniel
---------------------------------
Prof. Dr. Daniel Oberfeld-Twistel
Johannes Gutenberg - Universitaet Mainz, Experimental Psychology &
Laboratoire ICube UMR7357 Université de Strasbourg
Wallstrasse 3
55122 Mainz
Germany
Phone ++49 (0) 6131 39 39274
Fax ++49 (0) 6131 39 39416
http://www.staff.uni-mainz.de/oberfeld/
From: AUDITORY - Research in Auditory Perception <AUDITORY@xxxxxxxxxxxxxxx>
On Behalf Of Junfeng Li
Sent: Saturday, August 13, 2022 1:42 AM
To: AUDITORY@xxxxxxxxxxxxxxx
Subject: Re: On 3D audio rendering for signals with the low sampling frequency
Dear Frederick,
Thank you so much for the references that you mentioned.
"[...] up–down cues are located mainly in the 6–12-kHz band, and front–back cues in the 8–16-kHz band."
According to this statement, it seems impossible to solve the problems of elevation perception and front-back confusion when the output signal is sampled at 16kHz.
Though I know it is difficult, I always try to find some solutions.
The literature on the HRTF over the past 60 years has made it very clear that "[...] up–down cues are located mainly in the 6–12-kHz band, and front–back cues in the 8–16-kHz
band." (Langendiijk and Bronkhorst, 2002)
Here are a few places to start:
Langendijk, E. H. A., & Bronkhorst, A. W. (2002). Contribution of spectral cues to human sound localization.
The Journal of the Acoustical Society of America,
112(4), 1583–1596.
https://doi.org/10.1121/1.1501901
Mehrgardt, S., & Mellert, V. (1977). Transformation characteristics of the external human ear.
The Journal of the Acoustical Society of America,
61(6), 1567–1576.
https://doi.org/10.1121/1.381470
Shaw, E. a. G., & Teranishi, R. (1968). Sound Pressure Generated in an External‐Ear Replica and Real Human Ears by a Nearby Point Source.
The Journal of the Acoustical Society of America,
44(1), 240–249.
https://doi.org/10.1121/1.1911059
---------------------------------------------
Frederick (Erick) Gallun, PhD, FASA, FASHA | he/him/his
Professor, Oregon Hearing Research Center, Oregon Health & Science University
"Diversity
is like being invited to a party, Inclusion is being asked to dance, and Belonging is dancing like no one’s watching" - Gregory Lewis
Dear Leslie,
When downsampling to 8/16kHz, we really found the localization accuracy decreases, even for horizon
Do you have any good ideas to solve it?
I'd also wonder about the time resolution: 16KHz = 1/16000 sec between
samples = 62 microseconds
.
That's relatively long for ITD (TDOA) estimation, which would suggest that
localisation of lower frequency signals would be impeded.
(I don't have evidence for this: it's just a suggestion).
--Leslie Smith
Junfeng Li wrote:
> Dear all,
>
> We are working on 3D audio rendering for signals with low sampling
> frequency.
> As you may know, the HRTFs are normally measured at the high sampling
> frequency, e.g., 48kHz or 44.1kHz. However, the sampling frequency of
> sound
> signals in our application is restricted to 16 kHz. Therefore, to render
> this low-frequency (≤8kHz) signal, one straight way is to first
> downsample
> the HRTFs from 48kHz/44.1kHz to 16kHz and then convolve with sound
> signals.
> However, the sound localization performance of the signal rendered with
> this approach is greatly decreased, especially elevation perception. To
> improve the sound localization performance, I am now wondering whether
> there is a certain good method to solve or mitigate this problem in this
> scenario.
>
> Any discussion is welcome.
>
> Thanks a lot again.
>
> Best regards,
> Junfeng
>
--
Prof Leslie Smith (Emeritus)
Computing Science & Mathematics,
University of Stirling, Stirling FK9 4LA
Scotland, UK
Tel +44 1786 467435
Web: http://www.cs.stir.ac.uk/~lss
Blog: http://lestheprof.com
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