QC55 : the four-way coaxial unit
The design of the lens, holding the TC23 in front of
the 22” woofer on the same axis to form a four-way
point source, required very long theoretical and
experimental studies including tests of several versions
and numerous filter modules. The shape succeeds in
creating a portion of pulsating sphere with minimum
diffraction effects. The shape of the arms and of the
front panel of the lens contributes to the quality of the
high and mid frequencies, whereas the shape and the
damping of its rear side have been designed for the
low-midrange specifications.
A spherical enclosure
The spherical shape of the cabinet loading the woofer presents numerous advantages:
- rigidity inherent to the shape.
This is essential to avoid any low frequency vibration that might create noises or a fuzzy sound scene. Thanks to the resulting
extremely good pressure resistance, the shape allows use of a very small volume for a 22” woofer and thus provides 96 dB efficiency
and a linear response down to 20 Hz, in anechoic room conditions. Any other reference system specifying equivalent characteristics
in the low frequency range needs a minimum of four to six times more volume for the woofer(s).
- no standing waves.
There are no parallel surfaces, so it is not necessary to fill the enclosure with a lot of damping material and internal bracing. The use of
those items reduces the internal volume of air available to load the driver, thus requires the use of a larger volume, thus lager panels
that require more bracing and damping...
- perfect symmetry in every direction and no diffraction effects from 20 to 20,000 Hz:
The very essence of the spatial coherency.
There was a hitch when considering a full range spherical loudspeaker enclosure. A problem that required a long term collaboration
with a French designer, famous for his variations around spheres and circles, to answer the following question “which type of stand
will be able to position the tweeter from La Sphère at the optimal height, ensure a no compromise stability of the system even at very
high low frequency sound levels and will not create diffractions spoiling the response coherency out of axis?”
BASS
L. MEDIUM
H. MEDIUM
HIGH
Summary of Contents for LA SPHERE - DATASHEET 2
Page 1: ...La Sphère ...
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