Hi Richard
On 23/03/2011 11:08, Richard Lee wrote:
I think this is a virgin field of research.
But this discussion seems about much larger areas and apart from my crude
efforts, no one else seems prepared to report their experiences.
I note a deafening silence from the York& Derby Ambisonic Mafia who probably
have more experience with large area playback than the rest of the world put
together.
Silent? Moi?? But seriously, I haven't felt able to add much that wasn't just noise as I haven't
had any experience using line arrays
That's only strictly true for LF where Ambi is a (crude?) form or WFS ie when it attempts to
recreate the soundfield at a point. An IEC Listening Room, 2.5 x 6 x 4m is a "point" at 20Hz.
I wouldn't say it was 'crude' as, at the central point, it can be made as exact as the speakers will
allow - which may even be better than WFS as the speakers for that are generally somewhat
compromised by the need for them to be packed as closely together as possible (plus it's usually
only two dimensional at present)
While MAG's rE appears to predict what happens when this no longer holds true
on a domestic scale , we don't know how listeners react to large area Ambi
soundfields.
Please do pontificate on this subject but lets hear from those who have tried
stuff out so we can test these prophecies.
For low orders (and non-line speaker based systems) our experience over large areas is that even
though the accuracy of reproduction in terms of perceived source directions degrades rapidly as you
go away from the centre, the sound field remains "believable" over a reasonably large area. For
instance, I often demo our 16 speaker rig in our Rymer auditorium (4 up, 8 around, 4 down under the
audience, mostly Diamond V's - thanks Richard) using the fireworks and Concorde fly-past recordings
from the Ambisonia site and, although directions go wrong off-centre, they are still incredibly
believable and natural feeling - and that's first order!
Dave
You probably do need special decoders for horizontal ambi with "line" sources,
but what these need to do is a new field. I can only report from my small experiments,
that a normal Classic Decoder seems to work well.
Interesting - someone want to donate a bunch of good quality line sources so's we can do the
research? :-)
Dave
that's another thing worth exploring: the funktion one guys have reported that
ambi rigs have an advantage in this respect, because the ratio of useful
loudness inside to leaked emission outside of the array is better than with
stereo (or maybe even conventional four-point) playback systems.
This is very obvious even for domestic ambi systems.
As well as the very real sense of something real happening within the circle of speakers
when "viewed" from outside. Peter Lennox thinks it's just glorified stereo but
the effect is so startling that it must be more than that.
[1] Loudspeakers and the Stereo Seat - G Millward, HFN, 1981?
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