JAMO D 7LCR, Брошюра

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D 7LCR / D 7SUR / D 7SUB description
D 7LCR
D 7LCR is a 3-way speaker with two 5½”woofers, two 2½” midrange drivers and one 1”
tweeter, see more details about the driver units below.
The compact drivers improves the dynamics: As they weigh less they can move faster. Of
course under the precondition that they are equipped with very powerful motors
(magnet/voice coil) as is the case here.
The two midrange drivers are placed vertically over / under the tweeter and the woofers
are placed on each side of the midrange/tweeter array.
The crossover frequencies are 400 Hz and 2k Hz.
There are several advantages of these low crossover frequencies when you, as in this case,
have the drivers to match them.
Every diaphragm has a break up point and it is important that the driver is used in a range
where break ups are controllable or do not appear.
Of course the further away from the break up point the better. In
D 7LCR the crossover
frequency for the woofers is 400Hz and the diaphragm’s break up point occurs above 2k
Hz. Therefore using a 2’nd order crossover is fully applicable and phase errors that often
occur with higher order crossovers are avoided.
The two woofers in the
D 7LCR
are mounted horizontal beside each other which at higher
frequencies (over 2k Hz) normally would result in phase cancellation, when listening off
axis. However, since the x-over point is as low as 400 Hz this problem is eliminated.
The midrange drivers could easily work up to 4k Hz, but then again phase cancellation
would occur, just here in the vertical direction.
The tweeter takes over at 2k Hz to obtain a wide vertical dispersion - thus the listening
height is uncritical. Any listening height between 70 - 120 cm will result in a perfect
listening window. This is not done better with any “normal” configuration.
The resonance frequency of the tweeter is as low as 600 Hz, and when cut off at 2k Hz, it is
not stressed in any way. Therefore reproduction is very clear with a lot of “air” and details.
Due to the construction
D 7LCR has a very wide horizontal and vertical dispersion
resulting in a perfect listening window also in 2 channel stereo, where you typically listen
off axis.
The
D 7LCR
is magnetically shielded so it can be placed close to a TV-set.