Hi Fernando, Absolutely, I’m happy to make that recording available. Give me some time for that, I’ll need to adapt the implementation so that it outputs the ambisonics signals in a useable format.
The thing is, though, that the room was very noisy when I made that recording so that I’d want to find better content that allows for a more critical evaluation. I’ll speak with the guys from the audio communication group at TU Berlin who built the array, which was initially meant for motion-tracked binaural. I think that they made proper recordings of classical music and the like. I’ll see in how far they can share those. I’ll then convert them to 7th-order ambisonics. Best regards, Jens > On 14 Dec 2021, at 23:19, Fernando Lopez-Lezcano <[email protected]> > wrote: > > On 12/7/21 2:15 PM, Sampo Syreeni wrote: >> On 2021-12-02, eric benjamin wrote: >>> I believe that Nando may have been thinking about reproduction with >>> loudspeaker arrays. He has a system with eight loudspeakers on the >>> horizontal plane, as do I. So good up to third order. > > And I actually have access to a 56.8 system[*] (in our "Stage" small concert > hall), the main horizontal speaker ring is 20 speakers, so quite a bit more > potential spatial resolution than just 3rd order. > >> What is interesting here, to me, is that sampling on the recording side, and >> reconstruction on the playback side by discrete speakers -- also an instance >> of sampling in space -- are not the same, and they deteriorate the >> reconstruction of the soundfield separately. Sampling in recording array and >> sampling in reconstruction array...I've never really seen them analyzed at >> the same time, in the same framework. It's always been so that we go to an >> intermediate domain, which is continuous, with a little bit of wobble >> angularly, in noise or gain figures, and then back the same way. >> It's all whole and good, if you can assume independence in all of the errors >> on the way. But then, you can't: the above Swedish case which I've been >> arguing, *certainly* doesn't admit such symmetry or independence assumptions. > > Yes, there will be errors created by both the capture process (encoding into > ambisonics), and by the imperfections of the playback environment, be it > binaural or plain old speaker arrays. The errors will be mixed together... > >> So, the statistical asummptions which underlie e.g. Makita theory, and there >> Gerzon's, don't go through. In particular, since we're dealing with wave >> phenomena, there is interference to be contended with. That doesn't come >> through at *all* in statistical analysis, across 2D and 3D analyses; 3D >> coupling to a 2D sensor is *wildly* uneven, and if you have a box around the >> sensor, it can be shown that the sensor coupled with its idealized >> surroundings, can exhibit resonant modes which run off to an infinite >> degree, within an infinitely small degree, in angle. It will *always* be >> nasty, at the edge. >>> But I actually have 24 full-range loudspeakers available. Would it be >>> advantageous to expand our systems to higher order? >> When you have those, the next thing is, you need an anechoic chamber, and >> well-calibrated microphones. I mean, you have the machinery to launch >> physical signals, in 3D. Now you need measurement machinery to catch what >> you launched, and a silent space between which doesn't perturb your signals. >> Is it that not so? ;) > > Yup. While an ideal environment is best, we can try to do some testing done > in less than ideal circumstances. Let's assume we have some "machinery" in > place (reasonable playback environment, reasonable capture tools). > > The question (to me) is really: what do we actually measure once we have the > machinery in place? Are there objective criteria that can tell us what is > perceptually relevant? > > I would love to have the original 7th order recording that started this > thread, so that it could be played in different systems and with different > orders (Jens?). > > Or: we can build horizontal arrays (or 3d arrays, for that matter) with N > capsules, where N is an ever increasing number. > > What is the number of capsules and encoded order at which it does not make > sense to keep adding capsules (and spherical harmonic components). What is > the point at which "the incremental perceptual improvement, if any, is very > small and does not justify increasing the number of capsules needed to > capture higher orders". I know this would not be a black and white hard > limit, of course... > > -- Fernando > > [*] https://ccrma.stanford.edu/~nando/publications/stage_grail_2019.pdf > _______________________________________________ > Sursound mailing list > [email protected] > https://mail.music.vt.edu/mailman/listinfo/sursound - unsubscribe here, edit > account or options, view archives and so on. _______________________________________________ Sursound mailing list [email protected] https://mail.music.vt.edu/mailman/listinfo/sursound - unsubscribe here, edit account or options, view archives and so on.
