[M4IF Technotes] Sound2D: listening plane

[Oliver Baum]

Hi,
I have a question concerning the Sound2D node:
Refering to the Systems spec. (section 9.4.2.96.2) this node is intended 
  for the auralisation of 2D-objects in the screen plane; i.e. the 
virtual sound sources can be moved only in the xy-plane (in a 
right-handed coordinate system, where z is the axis coming out of the 
screen pointing to the viewer/listener).
Does this really make sense?
I am asking this because the playback hardware - at least the ones 
available today - allows virtual sound sources to be positioned only in 
the xz-plane, which is the plane the (5.1- or 4.0-) speakers are placed. 
To move sources in the xz-plan thus the Sound or DirectiveSound node has 
to be used, which requires at least the "audio", "3D audio" or 
"complete" scene graph profile according to section 19.3.3 of the 
Systems spec. -- even if the other parts of the scene require only e.g. 
the "advanced 2D" or "complete 2D" profile.
So wouldn't it be more handy to implement the Sound2D node's location 
field as coordinates in the xz-plane (in contradiction to the Systems 
spec.) or are these ideas completely wrong?
Comments and hints are welcome!
Greetings,
-- 
Dipl.-Ing. Oliver Baum
FhG IIS-A, Am Weichselgarten 3, D-91058 Erlangen, Germany
dept. Audio & Multimedia
phone: +49 (0) 91 31 / 7 76 - 39 51
mailto: baumor   iis.fhg.de