Citando Dave Hunt <davehuntau...@btinternet.com>:
From: Politis Archontis <archontis.poli...@aalto.fi>
Subject: Re: [Sursound] Enquiry on upmixing from 1st order
ambisonics to 3rd order ambisonics.
Date: 22 February 2019 18:15:00 GMT
To: Surround Sound discussion group <sursound@music.vt.edu>
Hi David,
These upmixing methods extract a lot of information from the FOA
recording that is then re-used to essentially “synthesize" the HOA
signals, with a spatial resolution that would not be possible with
the FOA recordings. They are “active” in that sense, and
signal-dependent, compared to the “passive" classical ambisonic
decoding. Their success depends of course on how effective is their
underlying model and how robustly they are implemented.
In that sense there isn’t necessarily a large benefit in parametric
upmixing from FOA to 3rd-order, compared to parametric decoding for
playback, since these methods can also upmix directly from FOA to,
say, 40 speakers or headphones, with their maximum sharpness.
However, the HOA upmixing could be useful for people that are
working with a HOA processing pipeline, and they want to integrate
FOA or lower-order material seamlessly.
Regards,
Archontis Politis
Very few people have access to microphones beyond FOA, so that in a
live recording a number of close microphones could be mixed in third
order, with a FOA microphone as a "room" mic.
I don't understand these permanent "objections".
The Octomic and the Zylia ZM-1 microphones are available and well priced.
Why not just doing some investment (for a longer time), and just buy
one of these?
COMPASS seems to be able to upsample 2nd and 3rd order to higher, so
you seem to have always some
advantage.
(To be confirmed after COMPASS gets available, of course.)
From persons claiming to be professional recordists I would actually
expect to use up-to-date equipment.
(The mentioned microphones don't cost more or much more than some
professional cameras - just to compare.
I expect that a real photographer... you know what I mean.)
Best,
Stefan Schreiber
For location recording, the FOA mic options are more robust, with
better weather protection, and more practical than any higher order
option.
In a "synthesised" third order sound field, FOA recordings could be
used as more "ambient" stems.
The up-mix is a re-coder, FOA to third order. What would follow it
is a third order mixer and a decoder to loudspeaker feeds. Other
third order sounds could be mixed into the decoder. More than one
FOA signal could be mixed into the re-coder. Whether it is better
that each FOA signal has its own re-coder is debatable.
If the re-coder includes its own identical decoder, which cannot be
bypassed, the two (or more) sets of third order decoder loudspeaker
outputs could be mixed together. The availability of an identical
decoder, and a suitable mixer might be problematic.
Ciao,
Dave Hunt
_______________________________________________
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.
