On Wed, Feb 24, 2010 at 05:01:20PM +0300, alex stone wrote: > Jorn, Fons, > > I'm getting deeper into a setup now, and trialling a few different configs. > > A further question. > > Given that an amb sphere is equal on all "sides", and the sweet spot > is the centre (roughly speaking), should i be configuring my dry sound > orchestral instruments/sections to use the upper-rear/rear quadrant of > the sphere, assuming the centre is the listener, in a total space? In > a real world setup, my orchestra is on the stage, and the listener may > well be (at my choice) sitting in a spot equidistant from the > back/front/left/right of the total space. Should i assume this as a > point of reference to begin with?
I get a bit confused. Usually 'the stage' is considered to be 'front', the positive X direction. You can decide otherwise when mixing Ambisonics, but in a normal concert hall the orchestra would be in the front direction. Upper-rear would be a balcony area, or just some walls. > My "speakers" will be not only on stage, but as ambient > sound/reflections in the rest of the space as well. The > space isn't exactly spherical. Don't think in terms of a 'spherical space'. Ambisonics as we use it here does not consider distance. Every point on the sphere just corresponds to a direction as seen from the center. It's just a mathematical abstraction, the set of directions in 3-D space is equivalent to the set of points on a sphere. Distance and the shape of the space are encoded in the time patterns of direct sound and early reflections. Concerning the virtual stereo microphone you asked about earlier maybe this can be explained as follows. An Ambisionic (B-format) signal, no matter how it was generated, can be considered as the output of a B-format microphone placed at a specific place in some sound field. You can use the B-format signals to compute the output that any normal mic would produce when placed in the same spot. Using two of such 'virtual microphones' pointing in different directions produces a stereo signal. It is the classic way to obtain a stereo version of an Ambisonic recording or mix. One of the plugins in the AMB set will do this. Ciao, -- FA O tu, che porte, correndo si ? E guerra e morte ! _______________________________________________ Linux-audio-dev mailing list Linux-audio-dev@lists.linuxaudio.org http://lists.linuxaudio.org/listinfo/linux-audio-dev