Archontis - I mean when I make a multichannel sound installation and use Vbap to pan it - lets say an eight channel octophonic horizonatal array - when I export an 8 channel interleaved rendering of this installation later and play it back on say, Iplayer, it automatically renders it to stereo and and panning is suprising well represented in stereo.
On 9 January 2017 at 12:19, Politis Archontis <archontis.poli...@aalto.fi> wrote: > Hi Sampo, > > > On 09 Jan 2017, at 06:27, Sampo Syreeni <de...@iki.fi> wrote: > > > > The critique I'd have for such panning laws is that they don't really > respect the ambisonic/Gerzon theory, especially at the low frequencies. In > essence, they work, and necessarily would *have* to work in the high > frequency, (ambisonically speaking) high order,sparse array limit. Which is > why they mostly work for common music and speech signals. > > I am a bit baffled by the idea that VBAP is not compatible with Ambisonics > theory (?) Thinking in terms of velocity and energy vectors, as far as I > understand, VBAP with the (classic) amplitude panning formulation has zero > angular error for the (Makita) velocity vectors for all directions. If you > take the energy formulation of VBAP for high frequencies (solving for > energies instead of amplitudes) then it results in the maximum (Gerzon) > energy vectors that the setup can achieve with zero directional error > again. Of course at low frequencies you cannot achieve the “perfect” > pressure reconstruction that a mode-matching decoder can achieve, but then > you see what are the gains that such a decoder imposes on not ideal regular > setups to realize that perfect reconstruction should be compromised anyway > with some more practical solution. > > > > However, they fail to work general speaker arrays fully. Especially at > the lower frequencies. Ambisonically speaking, where we'd go with a > holistic, whole array, directionally averaged velocity decode. > > Again I think it depends how you mean it - VBAP will just work for any > speaker array with a performance limited by the setup in a quite intuitive > understandable way (large spread for large triangle apertures, full > concentration at a speaker direction, nothing for regions outside a partial > setup etc..). Ambisonic decoding for any array is not designed as easily as > computing VBAP gains, and it seems for irregular setups, one of the most > straightforward and practical ways to do it is to combine the properties of > VBAP and Ambisonic decoding (as the work of Zotter, Batke, and Epain have > shown). Considering panning specifically, I think it depends on the > application what works best, for VR or interactive-audio stuff for example, > where normally sound objects would be rendered with maximum sharpness VBAP > would work better. If however some and more even directional spreading is > preferred, then ambisonic panning should be better, or some VBAP variant > with spreading as has been presented by Ville and others. > > So I find Augustine's comments reasonable on panning sounds, but not in > general: VBAP vs Ambisonics. > > > On 09 Jan 2017, at 12:33, Augustine Leudar <augustineleu...@gmail.com> > wrote: > > > > Yes i just mean - when making a 3D sound installation you can use various > > types of panning round a sphere (or whatever of speaker array). You > seemed > > to be saying ambisonics had a clear advantage over other types of panning > > for 3D audio - I was just wondering what you saw as ambisonics' > advantages > > over VBAP. I've actually found Ambisonics to be worse compared to VBAP in > > many situations and better in others - but generally I use Vbap or Dbap . > > The only real advantage I can see of ambisonics is having one file that > can > > be up or down mixed - but you can do that to a degree with Vbap files as > > well. > > (What is a VBAP file?) > > That’s if you have actually access to the sound objects with their > parametric information, in which case sure you can pan them however you > like, you can even switch between different panners on the fly and pick the > one you prefer. However, the generality of Ambisonics becomes clear if you > have real sound-scene recordings, or you don’t have access to the objects > due to bandwidth limitations, and it makes sense to downmix them to a > format that preserves their directional properties as good as possible. > This last case becomes especially important if decoding of some HOA > channels (or even FOA with parametric decoding) becomes perceptually > indistinguishable with respect to spatializing many of sound objects > separately.. > > Regards, > Archontis > > _______________________________________________ > 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. > -- Augustine Leudar Artistic Director Magik Door LTD Company Number : NI635217 Registered 63 Ballycoan rd, Belfast BT88LL -------------- next part -------------- An HTML attachment was scrubbed... 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