Snell AMC 2000THX, Руководство пользователя

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INTRODUCTION: WHAT IS A HIGH END IN-WALL?
The Snell AMC series units bring a novel approach to the design and construction of in-wall
loudspeakers, expanding the boundaries of in-wall performance.
Our primary goal was to develop loudspeakers that delivered performance that was as close as
possible to that of our highly regarded freestanding loudspeakers, like the LCR7 and C7. To do
this, several issues had to be addressed.
The bass performance of conventional loudspeakers mounted in wall cavities is very unpredict-
able. Cavity volume can be large, which should be good for bass performance. However, with
one very short dimension (approximately 4”) and one very long dimension (up to 8’), the wall
cavity takes on the characteristics of a closed-end organ pipe. This creates a strong resonance
that tends to null out the bass. Lining this cavity with fi berglass will reduce the “Q” of the
notch but not restore the bass. What is needed is a defi ned volume of a more regular size. This
is best done with fully enclosed in-wall speakers.
The Snell AMC loudspeaker enclosure is a thin, but strong, aluminum tub. It is both damped
and braced. This largely contains the back radiated sound of the woofer within the enclosure.
An added benefi t of containing the woofer output is a reduced chance that resonances will be
excited in the house walls. Furthermore, sound “bleed through” to adjacent rooms is reduced.
To minimize resonances in the Snell enclosure, the speaker baffl e uses a technique fi rst
pioneered on our .5 and XA series loudspeakers. The baffl e is a three part composite with MDF
(fi berboard) outer layers around a thin, but highly effective, damping layer. This controls the
panel resonances of the baffl e that can obscure midrange clarity. As we have found with our
freestanding loudspeakers, a better loudspeaker cabinet means a better sounding loudspeaker.
Conventional in-wall speakers also suffer from poor stereo imaging. Freestanding speakers can
be angled inward to produce a better central image and make listening position much less
critical. Obviously, most in-wall speakers obviously cannot be angled in this way. Some in-wall
speakers use a pivoting post-mounted tweeter in attempt to overcome this limitation. The piv-
oting mechanism produces refl ections that adversely affect the tweeter’s response and sound.
Also, the small baffl e area of the pivoting tweeters means that only the highest frequencies
can be angled inward. The AMC 2000
THX
has an optional angled mounting plate for the high
frequency and midrange drivers.
The AMC 900
THX
uses a different solution – a unique tweeter that incorporates a waveguide
with a fi xed 20 degree angle. The DPT (“Directed Power Tweeter”) waveguide design controls
refl ections to ensure smooth response. The waveguide is also large enough to function ef-
fectively over the full range of the tweeter.
In addition to these unique solutions, all traditional Snell attributes are retained. Highly coher-
ent in-phase crossover networks ensure a seamless blend from driver to driver. Drivers are
designed for smooth, wide range response and low distortion. Long sessions of listening and
adjusting give each system that special, characteristic Snell sound. Finally, that Snell sound is
guaranteed in every production pair by Snell’s proprietary 0.5dB production tuning techniques.