JAMO R 909, Technical Description

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9
TWEETER
There was only one choice when it came to choosing a tweeter to reproduce the
delicate treble frequencies… the legendary Revelator from Scan Speak. However,
since this model features a relatively large face-plate, it would have needed to have
been placed further away from the midrange than would be ideal. So, in order to
obtain a seamless transition with the midrange driver, we chose to fi t a smaller
cast-alloy face plate.
The tweeter features a 1in textile dome
which is coated several times to obtain a
unique combination of dynamic linearity
and resonance damping, the result being
an incredibly smooth, linear, dynamic and
incredibly transparent sound.
The driver’s Symmetric Drive Technology - a copper ring on the pole that extends
past the voice coil, curving into the dome chamber - practically eliminates
electrical phase shift. And, just as it does with the midrange, it also lowers distortion
signifi cantly.
To eliminate turbulence the double-damped, optimized chamber behind the
magnet system is also equipped with an anti-resonator-plug.
And the specially designed chamber under the cloth surround minimizes air noise
and compression. Actually this tweeter is so carefully manufactured that damping
unwanted resonances using ferro-fl uid - the usual way - is rendered unnecessary!
X-OVER
As should be apparent from the drive unit descriptions above, we wanted to start
out with drivers of immense fundamental quality, precisely so that we would only
need minimal assistance from the cross-over!
Consequently, the cross-over in the Jamo R 909 is of a relatively simple – in the most
positive sense of the word – low-order confi guration.
The advantages of using the 2nd order fi lters that are in the R 909 is that both
electrical and phase angles are kept at very small values, something that’s of great
importance both in terms of sound quality and the eventual load on the amplifi er.
The use of quality Solen foil-capacitors and air-coils in the crossover further ensures
sound quality.