[PD] Cubemixer with hdsp and 8 lodspeakers?

[IOhannes m zmoelnig]

hi

rodrigo at anorg.net wrote:
> I made some progress thanks. I took a look at the abcdefg 3D-Mixer from
> IOhannes (great stuff), which was a little easier for me to understand:
> http://puredata.info/Members/zmoelnig/abcdefg
> 
> and it has a documentation(!):
> http://iem.at/~zmoelnig/publications/abcde/
> 
> I think this is much more fun than computing b-format files, because
> evrything can be done in realtime. I still have to check out which output
> channel gets asigned to what speaker. I think this must correspond to the
> order of the angles.mtx file, where the positions of the speakers are
> written, but I'm getting some funny sound positions. Most probably some
> mystake of mine.
> It was rather easy to set everything up until now. Just a few more questions.

> - Is the cubemixer better (dispite of the gui) than the abcdefg-3Dmixer?
> It looks more fancy, but is there some important feature I'm missing?

well the CUBEmixer is kind of "abcdefg-ng".
i wrote abcdefg as my thesis somewhen in 2002. CUBEmixer has been
written in 2005 by a team of "senior" (the youngest coming into the
30ies...) programmers.

in abcdefg, a lot of things or done automagically: this in theory should
ease the setup of such a system. iirc, it even automtically degrades the
order of the ambisonic system if you only have a limited number of
speakers (e.g. 8).
while the AUTO is cool the MAGIC used to be a pain, since it takes a lot
of thought if you want to customize the whole system (patches are
autogenerated at runtime; editing these patches is a no-no.)
furthermore, abcdefg is not actively maintained any more (i haven't
looked into it for years...)

CUBEmixer on the other hand is much more static. but it has a
plugin/extension architecture (which of course is badly documented...)
which allows you to customize it much more easily.
the features of CUBEmixer are based on our experiences with composers
who wanted to "just use" our system, but had several ideas of "extras"
(like being able to route several channels directly to a speaker,...)
it is the software that we are currently using (heavily!): it is work in
progress, which means that bugs are fixed all the time.
otoh, it is currently really an expert system.


> 
> - IOhannes wrote: "you will also have to reduce the ambisonics order to 1st
> order only (which is b-format) since the number of loudspeakers must be =
> the number of ambisonic channels which are (n+1)² (with n being the
> order)"
> How do I reduce the ambisonic order in the abcdefg? Is this necesary for
> the abcdfg? Is it just about reducing the number of output channels from
> the encoder, in the abcdefg.conf file?

if i only knew ;-(
as said above, in theory it should be enough if the angles.mtx just
defines 8 speakers - the degredation should be done automatically. if
you can set the ambisonic order in the abcdefg.conf file, you should of
course do it (i don't have abcdefg installed on my machine, so i cannot
check)

> 
> - I've read in the documentation, that for sounds to come from the bottom,
> one has to put loudspeakers on the floor. Are the elevation angles for the
> position of the speakers in the angles.mtx file negative? Like 0 -90?

correct (although i wonder how you will put the speaker at this
position: most of the time you will not be able to produce sound that
will appear to come from below, unless you are able to put the audience
at a bridge in the middle of the room)

mfga.sdr.
IOhannes