
A I R L A Y E R
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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 in 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. They are also set up to produce sound
mainly from about 2 kHz to 6 kHz. As a result, their top end is more like what will be
reflected from the side walls of a concert hall, and the sonic reflections from the side wall
do not smear the image noticeably, as would the off-axis sound from a dipole or the
more usual wide dispersion cone/dome speaker. The benefit is the same sort of airiness
as with these more dispersive speakers, but without the drawbacks.
Setup
The airLayer tweeters are continuously 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 -10
dB is a good place to start. Their sound should not be obvious. The effect is meant to be
subtle and not call attention to the side tweeters, but help prevent attention from being
called to the main drivers.
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