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. But I actually have 24 full-range loudspeakers available. Would it be advantageous to expand our systems to higher order? I've been asking this question for a very long time. With higher order program material slowly becoming available, perhaps we can find out.
Eric Benjamin On Thu, Dec 2, 2021 at 5:57 AM Jens Ahrens <jens.ahr...@chalmers.se> wrote: > Hi Fons, hi Nando, > > Please excuse that I’m responding to both of you in the same mail. There > is sufficient overlap in the matters to keep the thread from diverging. > > @Fons: Thanks for the clarification! We will look into this. > > @Nando: (The question was what the high orders contribute.) > > It’s hard to tell how exactly the high orders contribute. One aspect is > the interaural coherence that needs to be appropriate. The other main > aspect is what I typically term the equalization: Below the aliasing > frequency, things are fine anyway. Above the aliasing frequency, the > spectral balance of the binaural signals tends to be more even the higher > the orders are that are present. The deviations from the ideal spectral > balance also tend to be less strongly dependent on the incidence angle of > the sound if higher orders are present. > > Much of the angle dependent deviations of the spectral balance can be > mitigated, for example, by MagLS so that the perceptual difference between, > say, 7th order and infinite order is small. I can’t tell if it gets any > smaller with higher orders. My (informal) feeling is that somewhere between > 5th and 10th order is where the perceptual difference to the ground truth > saturates, both in terms of equalization and the coherence. > > Best regards, > Jens > > > > > On 2 Dec 2021, at 11:20, Fons Adriaensen <f...@linuxaudio.org> wrote: > > > > Hi Jens, > > > >> I’m attaching Fig. 1 from the JASA article. > > > > Nothing was attached (or it got lost...) > > > >> If I’m not misreading, then the 7th order is available somewhere between > >> 2 kHz and 3 kHz and higher. Aliasing kicks in at around 4 kHz-ish. > > > > So the question is if this small range (less than one octave) actually > > contributes anything useful. > > > >> My guess is that it is not more or less sensitive than SMAs. > > > > I'd agree. > > > >> I’m as close as a few centimetres to the surface of the array. This > >> triggers a lot of the high orders at low frequencies, and if there > >> is something that is not ideal, then the low frequencies tend to go > >> through the ceiling. > > > > If they don't that could just be because their contribution at LF > > is filtered out anyway, e.g. if your A/B process includes high pass > > filters of an order at least one higher than the order of the > > component they act on. > > > >> How would I be noticing if the microphone mismatch is above > >> the tolerance level? > > > > One way uncalibrated capsule gains will show up is that after > > binaural rendering you get significant ILD at LF, which should > > never happen except for very close sources. > > > > This actually happened recently with a binaural rendering system > > I was working on. When the room sound (early reflections and > > reverb tail) was added, this resulted in excessive ILD at LF, > > and a perception of the room sound that was clearly biased to > > one side. > > > > The room sound in this case was from a real room, measured using > > an SMA. Analysing these measurements revealed capsule gain errors > > up to +/-3 dB. When these were compensated for, the problem > > disappeared. > > > > > > You could just measure the B-format polars at LF, but that would > > require an anechoic room. > > > > You could instead compute the theoretical capsule signals for a > > set of directions, apply some gain errors, send the result through > > your A/B process, and plot the result. > > > > The only thing that mitigates this problem is statistics: with > > a high number of capsules contributing to each harmonic, errors > > tend to average out to some extent. > > > > Ciao, > > > > -- > > FA > > > > _______________________________________________ > > 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. > -------------- next part -------------- An HTML attachment was scrubbed... URL: <https://mail.music.vt.edu/mailman/private/sursound/attachments/20211202/1eb60937/attachment.htm> _______________________________________________ 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.
