[rec.audio.high-end] Isobariks and standing waves

moskowit@paul.rutgers.edu (Len Moskowitz) (12/04/90)

Isobarik speaker systems have two in-phase speakers connected by a
sealed constant pressure tunnel.  One speaker radiates into the
tunnel.  The other radiates into the world.  A recent Speaker Builder
article stated that the tunnel length in an isobarik configuration
contributes to nulls and peaks at certain frequencies due to standing
waves.  If the tunnel is sealed and the two speakers move perfectly in
sync, there should be no induced sound in the tunnel, no standing
waves, and no peaks/nulls.

I wrote to the author and he says there really are peaks and nulls.
Can anyone explain why this happens?  The only reason I can come
up with is that the drivers are not well matched and don't really move
in sync.


Len Moskowitz