On 01/28/2016 10:12 PM, Bo-Erik Sandholm wrote:
I do understand that HOA can represent resolution of directivity in the mathematic domain better than FOA. But I am starting to suspect we are overworking something when we are talking of order 8 to 15?
talking about using order 15 to retain the fine details of hrtfs doesn't mean we have to use 384 loudspeakers. nor will your average smart phone break a sweat when dealing with a very-high-order intermittent stage.
but given the care that goes into obtaining precise hrtf sets and the sensitivity of listeners towards coloration, it seems appropriate to represent hrtfs in a way that retains their precision.
Is it realistic to even think of measuring individual HRTF response with that angle resolution?
i have a set of custom hrtfs measured by ITA in aachen that (off the top of my head, can't check right now) has 3° horizontal and 5° vertical resolution. the whole measuring process took less than 7 minutes, and i'm told they have refined their procedure a lot since then.
And is it even neccessary when we know the adaptability of the auditory system?
given that even with my own hrtfs, externalisation is still a problem because i can't seem to get the headphone/ear canal equalisation right: yes! yes!! yes!!! that is somewhat orthogonal to localisation precision, but it shows that adaptability has its limits: when the illusion breaks down, it breaks down completely.
As stereo works good enough over 45 degrees with 2 speakers and correct psycho acoustic setup and a good recording are we not aiming for a overkill system?
if you still think about signal processing in terms of circuit boards and wires or old-school economic elegance, yes. but if the difference is in typing create_HOA_convolver(3) vs. create_HOA_convolver(15) and my phone isn't even getting warm, who cares?
i guess it's understood that we're on the very flat end of the diminishing returns curve at order 15. but the cost is getting negligible, _and_ binaural has this habit of failing completely for some people in the presence of very subtle errors.
As a normal guy without training in listening for direction of sound sources I suspect I cannot really pinpoint many things in more than +-10 degrees without visual cues.
if it was only about directional precision, then i agree, unless we're talking augmented reality: if you're flying this fighter airplane, i'm sure you'd want the "INCOMING!" warning voice to be positioned a lot more precisely than your ability to localize it.
I remember old discussion results about ideal number of loudspeakers for horizontal FOA replay being 6 speakers. My goal is to have a device that can play through headphones a stereo or FOA recording and give me a minimum experience of listening to a stereo system or FOA setup with out of head sound and a stable position of the soundstage. I am not certain this is relevant in this discussion thread as we probably have different views of the goals and the path to the goals.
well, what do you care about the order in which the hrtfs are represented? you feed FOA in, you get binaural out, and unless your processor starts burning up, you'll never know that inside the black box, some very-high-order stuff might be going on.
if by quadrupling the processing power, i can get a robust 5% improvement in the rendering of first-order material, i wouldn't hesitate a second, except in very special cases.
-- Jörn Nettingsmeier Lortzingstr. 11, 45128 Essen, Tel. +49 177 7937487 Meister für Veranstaltungstechnik (Bühne/Studio) Tonmeister VDT http://stackingdwarves.net _______________________________________________ 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.
