yes, now we are back to my original comment,
stereo is problematic. The way I do stereo is
to use the 8-channel ring and mix the left annd
right hand signals down into L-R. That seems to
be the most satisfactory.

Another thing you can do is binaural. Place the
8 speaker signals through the HRTF, using the
known positions and then mixdown the 8 stereo
signals. I heard Jean Jacob Hoffman is doing this,
perhaps you can look in his site for suggestions.

Victor

>
> Victor,
>
> I think I'm pretty much with you now, and can verify both
> your 8-ring configuration and a comparable 4-ring (quad).
>
> What doesn't now seem to correspond, however, is stereo.
> The doc specifies speaker placement at 330 degrees and 30
> degrees. Following the logic that 0 degrees is east, this
> gives placement appoximately at mid back right (330) and
> mid front right (30). In terms of stereo field it covers
> the east quadrant rather than the desired north. My tests
> seem to verify this.
>
> Obviously the problem arises because coverage of the
> soundspace is not symmetrical. What do we do about this?
>
> Art Hunkins
>
> ----- Original Message -----
> From: "Victor Lazzarini" 
> To: "Art Hunkins" ; "Developer
> discussions" 
> Cc: 
> Sent: Thursday, July 12, 2007 5:43 PM
> Subject: Re: [Cs-dev] [Csnd] bformdec 8-ring
>
>
> >
> > > 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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