Janszen zA2.1 Owner's Manual - page 17
A I R L A Y E R
14
8
airLayer Option
The zA2.1 speakers are very directive in the vertical, and rather directive in the
horizontal. This serves to minimize the involvement of the room, thereby making
setup easier, and maximally conserving the recorded ambiance and the precision
of the image. With recordings that do not have realistically recorded ambiance
with well conserved phase information, a potential drawback is the perception of a
closed in soundstage, extending only from one speaker to the other.
The airLayer option comprises a high grade ring dome tweeter mounted outboard
on each speaker, firing sideways toward its near side wall. The purpose of
bouncing some sound off the side walls is to widen the soundstage and provide a
sense of spaciousness that can be missing from directive speakers such as the
zA2.1.
These tweeters are wired out of phase with the sound coming directly from the
front of the speaker, and the point source sound that reflects from the side walls is
not strongly correlated with the line source direct sound. As a result, the sonic
reflections from the side wall do not smear the image noticeably, as would the off-
axis sound from a dipole or wide dispersion speaker. The benefit is the same sort
of airiness as with these more dispersive speakers, but without the drawbacks.
Setup
The airLayer tweeters are fully adjustable with a rotary control knob between off
and way too loud. In the usual setup, with the side walls a few feet away, a setting
of -8 dB is a good place to start.
If the side walls are different distances from the speakers, or have different types
of materials, it is best to turn off the ESL bias supply and wait until there is no
output from that portion of each speaker. At this point, you can adjust the
airLayer tweeters for good center balance. Once that is done, you can turn the bias
supplies back on again, and test for overall effect. You can turn them up or down
and the balance will remain okay as long as you keep the difference in dB between
the two settings the same.