On 02/09/2016 02:16 PM, Martin Dupras wrote:
I have no objection to using fewer than 16 speakers; it's just the
maximum I have available to me.
I would use as many speakers as you can. No point in using less and
there's always a way to arrange them to provide a "reasonable" coverage
of the upper hemisphere.
In our "Stage" here at Stanford (a small concert hall, seats about 60-80
at most) we have a setup I have used for Ambisonics with 8 + 6 + 2
speakers (16 all in all - the room is rectangular and that is why I used
two speakers up). That is not optimal for 3rd order (vertical) but I
have played 3rd order materials there in a recent concert and it was
fine. I used a Slepian decoder calculated with ADT (the Ambisonics
Decoder Toolkit).
As in all domes with current decoders there is some elevation of the
sounds, that is, something that should be at 0 degrees elevation is
perceived a little "up" (maybe 6 to 10 degrees?).
Running some simple simulation code to see where to put speakers (using
the electron potential method), assuming a dome configuration and
tossing 16 speakers in the mix I'm getting 10 + 5 + 1 or 9 + 6 + 1
arrays most of the time (depends on the random starting conditions). If
I "force" 8 of the speakers to be at ear level then I get an 8 + 7 + 1
configuration - you may want a ring of 8 at ear level as that is a
common configuration (for playing non-Ambisonics materials). Not very
scientific but it is a start (there are many criteria with which you can
try to space speakers in a "uniform" way in a sphere or dome, this is
just one way to do it).
To see which one is best (or rather which one you like best) you could
calculate decoders using ADT for tentative arrangements and look at the
energy and velocity graphs, even for various orders. The one that is
most even wins :-)
Let us know how it works out!
Best,
-- Fernando
The reason I had not considered the icosahedron vertices setup is
because, according to the wikipedia page, it's capable of 2nd order,
not 3rd order. Is that not the case?
Again from wikipedia: "Since stacked rings are somewhat wasteful at
higher elevations and necessarily have a hole at the zenith, they have
been largely surpassed by hemispherical layouts since mature methods
for decoder generation have become available. As they are difficult to
rig and require overhead points, hemispheres are usually found either
in permanent installations or experimental studios, where expensive
and visually intrusive trussing is not an issue."
That's the whole reason why I was considering a hemispherical setup
originally. It talks about "mature methods for decoder generation" so
I (wrongly, perhaps) assumed that there were capable decoders, and
there would likely be already available "templates" or "typical
scenarios" to use as a starting point.
Thanks,
- martin
- martin
On 9 February 2016 at 22:02, Augustine Leudar <augustineleu...@gmail.com> wrote:
I know Im treading on thin ice here around all these ferocious maths
guys... but might it be that there is not a suitable array that uses 16
speakers? I know if you have 16 speakers you will want to use all of them
but an Icosahedron is only 12 speakers (vertices) but it might be the best
option.
Also you could try ICST ambisonics plugins in max - they let you put the
speaker array in and it adjusts accordingly.
On 9 February 2016 at 21:51, Martin Dupras <martindup...@gmail.com> wrote:
Thanks for all the responses. Much appreciated.
I'll re-phrase the question in light of some of the answers I've been
given.
I will be using third-order Ambisonics. My aim mostly is to experiment
to get a good sense of what is possible with Ambisonics with height. I
have experimented successfully with 8-channel planar Ambisonics some
time ago. My primary intent is to spatialise multiple monophonic
(synthesised) sources using 3rd-order Ambisonics spatialisation, and
the playback of mixed sources (spatialised monphonic and stereophonic
sources as well as B-format 4-channel recordings.)
At this moment in time, I have the opportunity to deploy (next week) a
16-channel array, so I would like some advice on a configuration that
would be a good start to experiment with Ambisonics with height.
Someone suggested that I consult the wikipedia page on Ambisonics.
That is indeed where I got the idea that an "upper hemisphere" setup
might be suitable, since I only have on this occasion 16 speakers.
There is however no suggestion as to what a suitable hemispherical
configuration might be for a 16-speaker array, which is why I asked my
original question.
So let me ask a new question. Given the constraint that I can only use
16 speakers at the moment, and that I need to deploy this next week,
can somehow point me in the direction of what might be a suitable and
reasonable geometric configuration to try out? It seems to me that the
only really practical options here are two stacked rings (stacked
octagons) or a hemisphere. I would have thought that the hemisphere
would be the better choice, and in my scenario, a full lighting rig
allows me theoretically speaking to have speakers at the required
positions.
Again, thank you for all the responses.
- martin
On 8 February 2016 at 15:19, Martin Dupras <martindup...@gmail.com> wrote:
Hi,
I'm intending to try setting up a 16-speaker Ambisonics array next
week in a small TV studio. I'm trying to figure out the practical
arrangements for setting up the speakers. I was wondering if anyone
with experience might be able to offer some advice or point me in the
right direction?
What I'm planning at the moment is a half-sphere arrangement which
would likely consist of:
- 8 speakers in a circle of radius 2m at a height of approximately 1.6m
- 6 speakers in a smaller circle at an elevation of 45 degrees
- 2 speakers at an elevation of approximately 75 degrees
Alternatively, I would be happy with an arrangement similar to the
first 16-speakers in this diagramme:
http://www.matthiaskronlachner.com/wp-content/uploads/2013/10/loudspeaker-plan-observatory.jpg
I've been trying to find out if there is a convention or "most usual"
arrangement but couldn't find anything. I'm not particularly attached
to the actual arrangement, I just want to find an arrangement that
will work well enough with 16 speakers. Any advice?
The other thing I would welcome is advice on how to mount the speakers
to lighting rigs in a manner that is practical enough to offer some
good compromise between precision and ease of setup. I believe the
speakers we'll be using for the upper tiers will be Genelec 8060s.
Many thanks. Any advice will be greatly appreciated!
Cheers,
- martin
_______________________________________________
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.
--
www.augustineleudar.com
-------------- next part --------------
An HTML attachment was scrubbed...
URL:
<https://mail.music.vt.edu/mailman/private/sursound/attachments/20160209/6d5ca824/attachment.html>
_______________________________________________
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.
_______________________________________________
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.
