Best of the year 2012-2013 - page 6

"
At 300Hz
we run a 2nd-order electrical high-pass filter on the MSW which
adds to its 12dB mechanical roll -off. Though the driver has useful output to
80Hz, it stops operating as a pure bending wave generator below 200Hz.
There it begins to superimpose pistonic behavior on the bending wave. This
increases distortion to make unattenuated use down to 80Hz undesirable.
The 4th-order low-pass on the polarity-inverted woofer is matched to be
phase
constant
in the crossover frequency window. We're quite mercenary
about observing proper step and time response behavior and this mix creates
the
very
best
blend
between
the
two
drivers.
"The air volume behind the MSW is 8 liters. This creates a sealed sub
chamber which begins right below the driver and runs diagonally up toward
the rear wall. The Burr Brown op-amp based analog filter network is built into
the amplifier module while a separate chamber at the base of the speaker
houses the power transformer. This leaves 20 liters for the sealed woofer
enclosure whose F3 of 30Hz exploits some electronic compensation to
extend
the
raw
40Hz
response
by
another
10
cycles.
"Selectable trim pot or switch parameters include input sensitivity of 0.75 or
1.55V; input trim from -2.5dB to +2.5dB over 11 steps; polarity inversion; a
2nd-order 80Hz AV filter; a -6dB nearfield bass attenuator; a 100Hz high-pass
adjustment for +3dB/0dB/-3dB/-6dB; 3.25kHz nearfield and home cinema
compensation (+3dB/0/-1.5dB/-3dB) wher e boost addresses placing the
speaker behind a projection screen; and 10kHz shelving (+2dB/+1dB/0dB/-
1dB/-2dB) which responds to overly damped or reflective rooms. The
recessed M8 threads beneath the aluminum plinth can take spikes or other
floor interfaces at the user's discretion. We don't provide any.
1,2,3,4,5 7,8,9,10,11,12,13,14,15,16,...17
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