On 01/05/2011 03:55, Stefan Schreiber wrote: ..
It is fair to say that 1st order AMB is good (or "good enough"?) for some things, but it is not "perfect surround sound forever". Some people on this list are actually using 2nd/3rd and higher order Ambisonics, and I think that any good standard should consider different applications/requirements.
Sounds reasonable, and I would be much inclined to agree, but the problem is that there are so many different applications/requirements, that catering for them all (where "all" seems to be uncountably large) leads ineluctably to extreme complexity. The ultimate support-everything HOA file format (along with the tools with which to create and use it) has yet to be announced, as far as I am aware.
Frankly, if .AMB format includes B format (1st order), I don't see any fundamental conflict < at all >.
The .amb format (simple fmh recipes) supports up to 3rd order, as the channel counts for each combination are unambiguous.
The issue for me is no so much the encoding (though asking content providers, a.k.a. composers, to supply even a 9-channel file is IMO pushing it), but the decoding, where the number of speakers required seems to have its own version of Moore's Law. If encoding in 3rd order means you can get a[n even] better decode to 5.1, well and good; easy enough to understand why game developers would do that, to get the best possible experience over the one truly existing and established surround standard.
For outreach purposes (promoting periphonic as well as horizontal surround, promoting composers working with space) people need to talk up the "simple" affordable layouts and delivery formats rather more than has so far been done. The vast majority of works posted to Ambisonia have been plain 1st-order; a few IIRC are second order. So managing with the smallest possible channel counts at both encode and decode stages remains IMO an important strategic as well as an engineering objective.
The danger with the arguments that, say, third-order is actually not good enough is that commercial developers will just not touch Ambisonics at all, since it is a territory that is forever changing and remarkably lacking in consensus. It has taken long enough for 5.1 to reach lower price-point DAWS. When even 7.1 is exotic, nobody is going to make a DAW with a 16 channel bus only to be told a year later that "we need more".
Have any listening tests actually been carried out to establish what "typical" users consider to be sufficiently good localization? The higher orders are sold as offering the most precise localisation; but it seems to be more of an assumption than a proven fact that localization (as distinct from "separation") at that level is actually desirable.
At the end of the day, the problem is that HOA is not one standard but a multitude of them - each combination and size of order, and size and shape of speaker array, constitutes a separate "standard".
So the final question is: if you had to choose just ~one~ HOA standard for general production and delivery, to embed in the modern equivalent of the AD7 (or in some future generation of Logic Pro), what would it be? Or is that question simply unacceptable in principle?
Richard Dobson _______________________________________________ Sursound mailing list [email protected] https://mail.music.vt.edu/mailman/listinfo/sursound
