On 01/07/2011 12:58 PM, fons@xxxxxxxxxxxxxxx wrote:
On Fri, Jan 07, 2011 at 11:10:41AM +0100, Jörn Nettingsmeier wrote:
for those non-ambiheads wishing to follow this discussion:
the near-field effect in ambisonics results in a bass boost. it's
caused by the speakers. ambisonic theory (without NFC) assumes plane
waves, i.e. speakers that are very far away, so that the wave fronts
are not curved. since they are curved in practice, you get the bass
boost. the same thing is responsible for the well-known proximity
effect on directional microphones.
Not exactly. For a well-designed decoder the pressure at LF will
be proportional to W, even without NFC, and should not have any
bass boost.
need to double check, but iirc i did hear a very pronounced (read:
unbearable) boominess on my organ recordings when listening to them on
my <4m array in second order without NFC...
What you get in that case is a velocity field that
does not match the pressure in level,
this i understand.
and more important - in
phase, and this sounds very unnatural.
this is news to me. where does this phase delay come from?
I'm pretty sure that uncompensated NF effects in reproduction
systems are partly to blame for the 'you can't hear the direction
of LF sources' myth.
interesting hypothesis.
i guess the myth is more correctly formulated as "you can't localize
anything except some select and very obvious mid-frequency cues in AB
stereo". of course, bose and friends would jump on this to sell
ridiculously small satellites with woofers going up to 300 hz :)
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