9
The woofer operates without break-ups until 2k Hz, which is far beyond its working range
as the x-over frequency is 400 Hz.
Instead of a dust cap, the driver features a solid aluminium centre plug. This construction
results in effective heat disposal and prevents airflow obstruction when the diaphragm
moves.
The result is clean, natural and detailed sound reproduction.
(Sub)Woofer
The 15” woofer features a vented double magnet system and a
capton voice coil former, 65 mm in diameter and 40 mm long.
The 4 layer voice coil and the double magnet system make the
motor of the driver very powerful, capable of very high power
handling.
The diaphragm is made from
polypropylene which is very rigid
and the foam surround allows fast movement at its low
frequency working range.
The long throw woofer is capable of linear movements up to +/- 15 mm.
It is equipped with a transducer
at the back of the diaphragm that measures the
acceleration, which is used for the
MFB servo control
.
Electronics (D 7SUB)
Amplifier
The
D 7SUB
features a
400 Watt
Class D amplifier that operates at a highly efficient 85%.
This means that 85% of the power consumption is dedicated to the speaker, and only 15%
is dissipated as heat.
MFB (
Motional Feed Back
), servo control
We have given precise timing extremely
high priority in the D 7 design. To enable
the relatively compact subwoofer to reach
very low frequencies with perfect timing
the D 7SUB features
MFB
.
Even at high SPL the sound is precise and
distortion very low.
Thanks to
MFB
the driver “overshoot” is
dramatically reduced adding to the perfect
timing. The figure shows the overshoot of a
woofer with and without MFB.
MFB controls the woofer and eliminates the overshoot very quickly. The woofer is simply
able to start and stop correctly.
D 7SUB Woofer with transducer
