Hi Pierre, That's a very real approach which has been used quite often in the past, either with single speakers or even stereo pairs embedded in the system (cf Thomas Chen's B+ format or the report I did on the system we used for the Mystery Plays here in York back in the early 90's). The problem is that the presence of a source that is clearly tied to a physical speaker rather spoils one of the main advantages of field reconstruction technologies like Ambisonics and WFS, namely that individual speakers disappear, i.e. are not perceived as separate sources.
If you want sources inside the array without the problems mentioned then you need to look at something like ultrasonic interference imaging or time reversal acoustic mirrors, both of which can create internal sound sources. The latter is related to the techniques used by WFS or NFCHOA, so probably doesn't meet your criteria of creating a real sound source, but the former creates a real source. Currently, afaik, this is only used for LRAD weapons systems (http://www.lradx.com/) or acoustic spotlights (http://www.holosonics.com/technology.html) where the ultrasonic sources are grouped together and generate a beam of audio, but if the ultrasonic transducers are widely separated but all pointed at a single spot, the sound source will be at the intersection of the beams are thus an apparently "sourceless" source. Finally, just to say that experience has shown that moving sources and fixed (or slow moving) ones are different. Reasonably fast moving sources, at least in reasonable dry acoustics, can be made to seem to "fly past" close to the listener, if both early reflections and proximity effect are properly simulated, even on low order systems. Not the same as being able to walk around a source but interesting nevertheless. best regards, Dave On 13 December 2012 09:07, Pierre Alexandre Tremblay <tremb...@gmail.com> wrote: > Dear all > > Let me be a little teasy and controversial here: > >> Focussing, no matter >> how it's done, does not create a source. > > With that many speakers in a hall, you do happen to have a lot of real > sources you can use... > > It could be amazing to think of a real hybrid system where point-source > loudspeakers are used when a real point is needed, which is where all fantom > image systems fail, some of them more gracefully indeed... > > My 2 cents. > > p > _______________________________________________ > Sursound mailing list > Sursound@music.vt.edu > https://mail.music.vt.edu/mailman/listinfo/sursound -- As of 1st October 2012, I have retired from the University, so this disclaimer is redundant.... These are my own views and may or may not be shared by my employer Dave Malham Ex-Music Research Centre Department of Music The University of York Heslington York YO10 5DD UK 'Ambisonics - Component Imaging for Audio' _______________________________________________ Sursound mailing list Sursound@music.vt.edu https://mail.music.vt.edu/mailman/listinfo/sursound
