JAMO D 7SUB, Брошюра

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The magnet features a vented pole piece leading into a chamber at the backside. The
chamber and the “ventilation hole” in the pole piece are tuned in for achieving the very
low resonance frequency at 600Hz (normal res. freq. for a tweeter is around 1.5k Hz).
The voice coil former is made of aluminium for optimum heat disposal. The voice coil is
made of cupper plated aluminium wire, because aluminium weighs less than cupper, but
the copper plating is needed because of its conducting qualities.
In fact, the choice of “motor” materials makes use of magnetic oil for cooling and
resonance damping superfluous!
The “wire” from the driver’s terminal to the voice coil is a thin litz wire. Usually, the voice
coil wire continues to the terminals. However, litz wire features much higher compliance
and therefore it has less influence of the movements of the voice coil.
All these features in combination allow the diaphragm to move effortless and the result is a
very natural, detailed, dynamic and open sound reproduction.
Midrange
The 2½” midrange was developed especially for the
D 7 as it
had to fit into our high demands to the system.
The compact size alone makes it very fast - resulting in good
dynamics.
The sound is very open and detailed.
The unit is equipped with a rigid polypropylene diaphragm.
The surround is made of rubber, providing excellent
absorption of edge reflections.
The diameter of the voice coil former is 25 mm - quite large for a 2½” unit.
The large voice coil in combination with a powerful neodymium magnet, results in a very
powerful motor, making the unit capable of high sound pressure level/power handling.
The magnet is magnetically shielded.
Woofer
The 5½” was also developed specially for the
D 7 .
The aluminium diaphragm material was chosen due to high
rigidity and the fact that it is “airtight” (the air pressure
inside the cabinet cannot penetrate the diaphragm).
A pattern of small round stamps in the diaphragm makes it
even more rigid.
The basket is made from rigid and open-structured ABS.
The ABS material features a higher internal damping than
that of a conventional metal basket.
The open structure of the basket, also behind the spider, ensures high airflow and prevents
under- /overpressure at low frequencies - allowing free and fast movement of the
diaphragm. This becomes an extremely important feature as excursions of +/- 8 mm were
necessary in order to achieve the required SPL from the compact woofer.
D 7 Midrange
D 7 Woofer