|
> I observe two issues:
> 1) Your zero-degree point is 90 degrees to the listener's
> right. The documentation implies that zero is immediately
> in front of the listener (this is also intuitive).
> 2) The documentation implies clockwise movement (as
> degrees increase), not counterclockwise movement. This
> clockwise movement implies channel/speaker numbers
> increasing with clockwise movement.
That's right, the documentation is problematic. 0 degrees
is right (east), 90 is front (north), 180 left (west) and
270 back (south). This is not so counter-intuitive, as it
just a trigonometric circle.
>
> Would you agree that your speaker setup, reinterpreted in
> light of the above, is the equivalent of the following
> stereo pairs (front to back) - rotated 90 degrees
> counterclockwise (to put zero straight ahead) and with
> numbering reversed (so as to rotate clockwise): (8,1)
> (7,2) (6,3) (5,4) or outc a8, a1, a7, a2, a6, a3, a5, a4
> (with respect to bformdec outputs)
I am not sure I follow it. The speaker setup is as I gave
in my e-mail and that is what should be figured in the
manual page. Angles are not clockwise. It's just easy
to apply the numbering I gave. The numbering I gave is
for stereo pairs (L, R) front to back. The one you listed
does not work. Front is 3,2 (not 8,1) etc.; so you will
have:
a1,a2,a3,a4,a5,a6,a7,a8 bformdec ...
outq a3,a2,a4,a1,a5,a8,a6,a7
if you have the following speaker/channels from the
front:
1 2
3 4
5 6
7 8
>
> Furthermore, I assume that applying all the same reasoning
> to quad, but with the usual quad numbering (channels) for
> outq (LF = 1, LR = 2, etc.): outq a4, a3, a1, a2
> (With this setup, quad ambisonics seems to work for me.)
I have not tested quad, so I can't tell. I suggest it would
be RF,LF,LB,RB (counterclockwise starting from RF).
>
> Somehow, I should think we need to get csound's ambisonic
> audio output into a format that is readily understandable
> by all. To my mind, the out statement is the place to do
> this.
I hope this is clearer.
>
> Art Hunkins
>
> ----- Original Message -----
> From: "Victor Lazzarini"
> To: "Developer discussions"
> ;
> ; "Art Hunkins"
> Sent: Thursday, July 12, 2007 1:47 PM
> Subject: Re: [Csnd] [Cs-dev] bformdec 8-ring
>
>
> > Ok, we'll leave the angles out. Say your speaker
> > set up for a ring is:
> >
> > 1. mid front right
> > 2. front right
> > 3. front left
> > 4. mid front left
> > 5. mid back left
> > 6. back left
> > 7. back right
> > 8. mid back right
> >
> > Then you can plugin bformat outs 1-8 straight into 1-8.
> >
> > If you are working pair-wise L-R from the front, then
> > your pairs will be bformat outputs (3,2) (4,1) (5,8) and
> > (6,7).
> >
> > I hope this clears it up.
> >
> > Victor
> >
> >
> >
> >
> >
> >
> > >
> > > I am very confused, and it may well be at least partly
> > > on the conceptual level.
> > >
> > > I'm trying to understand the bformdec documentation.
> > > It describes speaker placement, for quad, as starting
> > > at right front and running clockwise to left front. It
> > > also references degrees (on a unit circle), with
> > > straight ahead being zero degrees and degrees moving
> > > clockwise through 360. I think I understand this so
> > > far. (No reference is made to angles; since I am
> > > math-challenged, I would like to leave them out of the
> > discussion.) >
> > > If one is dealing with quad output from bformdec:
> > > a1, a2, a3, a4 bformdec
> > >
> > > the output options seem to be:
> > > 1) outq a1, a2, a3, a4
> > > requiring verbal explanation of what this actually
> > > means in terms of speaker placement (as in "channel 1
> > > is RF, channel 2 is RR" etc.; or
> > >
> > > 2) outq a4, a3, a1, a2
> > > reinterpreting bformdec's output in terms of normal
> > > quad speaker/channel terminology - which (if I
> > > understand correctly) is LF = 1, LR = 2, RF = 3, RR =
> > 4. >
> > > I've less idea what such a reinterpretation might be
> > > for 8-channel circular mode. I've made the assumption
> > > (which certainly needs explanation to the "user") that
> > > the (normal?) counting of channels procedes in stereo
> > > pairs from front to rear. Assuming this, the output
> > > line would read: 2) outo a8, a1, a7, a2, a6, a3, a5,
> > a4 >
> > > I'd much appreciate being shown the error of my
> > > assumptions and thinking. There's either something
> > > wrong with my thinking, or with bformdoc, because - as
> > > I mentioned before - I'm not getting expected results
> > > with either quad or 8-channel bformdec. Using my test
> > > file, there is no speaker arrangement in which get a
> > > clear circular movement through 360 degrees. The
> > > placement is simply wrong, particularly in the range
> > > from 90 - 270 degrees. (I'm depending principally on
> > > strong aural and visual LED evidence in a quad
> > setting.) >
> > > Victor is happy; I'm not.
> > >
> > > And I'd still like to try out john ff's proposed
> > > bformdec, if there's any way to do so.
> > >
> > > Art Hunkins
> > >
> > > ----- Original Message -----
> > > From: "Victor Lazzarini"
> > > To: "Developer discussions"
> > > Sent: Thursday,
> > > July 12, 2007 10:10 AM Subject: [Cs-dev] bformdec
> > 8-ring >
> > >
> > > > Dear all,
> > > >
> > > > I just ran the bformdec using the 8-ring setup in
> > > > the studio and as I said before here it works as
> > > > expected. The speaker positions are as follows:
> > > >
> > > > bformdec out speaker pos
> > > > (degrees) 1 22.5
> > > > 2 67.5
> > > > 3 112.5
> > > > 4 157.5
> > > > 5 202.5
> > > > 6 247.5
> > > > 7 292.5
> > > > 8 337.5
> > > >
> > > > Angles are measured counterclockwise from the right,
> > > > so right -> 0, front ->90, left ->180 and back 270.
> > > >
> > > > Victor
> > > > Victor Lazzarini
> > > > Music Technology Laboratory
> > > > Music Department
> > > > National University of Ireland, Maynooth
> > > >
> > > >
> > > >
> > >
> > > >
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