SECOND HARMONIC DISTORTION
comparison of response at crossover frequency
comparison of Faraday ring effect
Acoustic intelligence
You don’t have to be a genius to understand why Q Series speakers sound so good. After all, they incorporate
the Uni-Q technology originally designed for one of the world’s finest speaker ranges, KEF’s legendary
Reference Series.
The Uni-Q concept is based on using aerospace materials to make the tweeter small enough to
place at the acoustic centre of the bass/midrange cone. With both drive units on exactly the same
axis and sharing the same waveguide, they behave as a single point source that projects a more
natural sound image over a much larger area than the usual tiny ‘sweet spot’.
This is because the Uni-Q configuration eliminates the inherent problems of having the separate
midrange and high frequency drive units of a conventional speaker. As loudspeaker radiation
varies according to frequency, LF and HF drivers have intrinsically different radiation patterns
whose directivity - known as ‘Q’ - changes at the crossover frequency. Interference (or ‘lobing’)
between the two units causes a dip in power response around this frequency, with a peak above
it due to their differences in directivity. These factors introduce colourations that muddy the
sound image. You get no such problems with Uni-Q. Being coincident and perfectly time-aligned,
the directivity of both LF and HF units is controlled by the profile of the midrange cone, with no
possible path or phase differences between the two, and no ‘lobing’ interference at the crossover.
The ‘Q’ is unified, in other words - hence the name.
So instead of narrowing towards the crossover and then widening again as is the case with
separate drive units, the Uni-Q radiation pattern remains stable. Power response is uniform,
with smoother variations on and off-axis. The acoustic image is better balanced and more natural
sounding across both direct and reverberant fields. Multi-channel imaging is noticeably clearer and
more accurate.
The Uni-Q array in the Q Series incorporates a sophisticated new tweeter with an aluminium
dome that increases the break-up resonance to 34kHz (as compared to the 25kHz threshold
of a typical standard dome).
The MF voice coil is of copper-coated aluminium ribbon,
expensively edge-wound over a polyimide former to increase sensitivity by maximising the amount
of copper in the magnet gap.
The chassis are of precision-cast aluminium for greater rigidity, with a vented design to improve
power handling. The tall profile cone surrounds are of butyl rubber to allow greater excursion,
and therefore higher output. Faraday rings are incorporated into the ultra-low distortion
motor, further reducing harmonic distortion by as much as 20dB. And audiophile-grade
crossovers are connected to the shrouded bi-wirable terminals to ensure the cleanest possible
signal transmission.
With refinements like these, no wonder the sound is so open and natural. No wonder the action
on screen suddenly becomes more compelling. No wonder you get so utterly immersed in the
listening experience. It’s what Q Series is all about.
Содержание iQ1
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