On Sun, May 23, 2021 at 04:57:30PM +0100, Stefan Schreiber wrote: > (If ACN/SN3D in the above sense adds anything to Jerôme Daniel’s thesis of > 2001 is another question.
What do you mean by 'adding anything to the thesis' ?? > ACN/N3D is also in wide use, supported by Mpeg, by ITU standards, and > still others. The traditional argument for N3D against SN3D is that N3D would force the omni (W) channel down because the higher order signals have higher gain, and that would reduce the available dynamic range. That is true for a single encoded source, but not for a complex mix of sources in all directions. And if you think about the gain structure of a complete system (including decoding to speaker signals), that is how it should be: a single source will be reproduced by only a few speakers, so it can never have the same SPL as a complex surround signal at maximum level. Since W represents the mono mix, its maximum level for a single source *should* be lower. So the rational choice would be N3D. In order to obtain the same headroom using SN3D, the overall level must be lower, with additional gain at the receiving end to compensate. This completely negates any S/N advantage that SN3D is supposed to have. I actually mentioned this in the meetings that resulted in the Ambix format, but lost the vote. 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.
