you can move head in relation to shoulders - tilt, rotate and so on - and shoulders in relation to head (eg lift one shoulder) - so although these can all be mapped to a cartesian frame of reference, that might not be the best way to mathematically represent it - for instance, you might curve the spine, then normalise the axis running thru' the ears with respect to the horizon, resulting in an effective shoulder tilt with respect to the head... and so on) So, think of the number of combinations of head-shoulder-horizon relationships, then ask how these can be experimentally simplified - and in doing so, you have to justify the simplifications on perceptual grounds, i.e. what computational economies are pragmatically justifiable... Dr. Peter Lennox Senior Fellow of the Higher Education Academy Senior Lecturer in Perception College of Arts University of Derby
Tel: 01332 593155 ________________________________________ From: Sursound [sursound-boun...@music.vt.edu] On Behalf Of Stefan Schreiber [st...@mail.telepac.pt] Sent: 27 February 2016 18:57 To: umashankar manthravadi รง; Surround Sound discussion group Subject: Re: [Sursound] OSSIC Kickstarter Campaign Begins umashankar manthravadi wrote: > I was trying to say something else. The head moves independently of > shoulder position. Pinnae are rigidly linked to the head; the > shoulders are not. That is what made me think the two should be > treated separately. > > > > umashankar > Sorry for coming back "late": The head < can > move independently of shoulder position, if the reference is the "HRTF sphere" - or simply say "outside world". :-) (There are two ways to change the position of yours ears: Your whole body moves, you move just your head vs. a fixed torso - and obviously you can have all combinations.) The visual case (eye movement) is very similar. There are two basic ways to move your eyes, i.e. to change your view: http://www.roadtovr.com/hands-smis-gear-vr-eye-tracking-accurate-fast-lightweight/ In both cases (eye, ear movements) you have two degrees of freedom. Best, St. > > > Sent from Mail <https://go.microsoft.com/fwlink/?LinkId=550986> for > Windows 10 > > > > From: Stefan Schreiber <mailto:st...@mail.telepac.pt> > Sent: Friday, February 26, 2016 8:07 AM > To: Surround Sound discussion group <mailto:sursound@music.vt.edu> > Subject: Re: [Sursound] OSSIC Kickstarter Campaign Begins > > > > Stefan Schreiber wrote: > > > Augustine Leudar wrote: > > > >> do you have a reference/source for that - that shoulder head > reflections > >> dont matter in anechoice etc etc - I would be interested to read it... > >> > >> > > They just arrive later than direct sound. And if the HRTF length is > > too short and so you don't have the sample length to capture (any) > > reflections... > > > > Clear? Or did < I > miss something? > > > > St. > > > Ok, I stand corrected: > > http://alumni.media.mit.edu/~kdm/hrtfdoc/section3_4.html#SECTION0004000000000000000 > <http://alumni.media.mit.edu/%7Ekdm/hrtfdoc/section3_4.html#SECTION0004000000000000000> > > > In order to reduce the size of the data set without eliminating > > anything of potential interest, we decided to discard the first 200 > > samples of each impulse response and save the next 512 samples. Each > > HRTF response is thus 512 samples long. < Most researchers will no > > doubt truncate this data further. > > > > > 44.1 kHz sampling rate > > As the speed of sound is about 340m/s, you will capture shoulder > reflections even with just 128 samples. > > > (If your ear-shoulder distance is about 20cm, the shoulder reflections > will arrive about 40cm delayed compared to direct sound, i.e. about 1,2 > ms later. > > 128/44.100 = 2,9 ms.) > > Best, > > Stefan > > > > > _______________________________________________ > Sursound mailing list > Sursound@music.vt.edu > https://mail.music.vt.edu/mailman/listinfo/sursound - unsubscribe > here, edit account or options, view archives and so on. _______________________________________________ Sursound mailing list Sursound@music.vt.edu https://mail.music.vt.edu/mailman/listinfo/sursound - unsubscribe here, edit account or options, view archives and so on. The University of Derby has a published policy regarding email and reserves the right to monitor email traffic. If you believe this was sent to you in error, please select unsubscribe. Unsubscribe and Security information contact: info...@derby.ac.uk For all FOI requests please contact: f...@derby.ac.uk All other Contacts are at http://www.derby.ac.uk/its/contacts/ _______________________________________________ Sursound mailing list Sursound@music.vt.edu https://mail.music.vt.edu/mailman/listinfo/sursound - unsubscribe here, edit account or options, view archives and so on.
