Whitepaper

6
In the development of the tweeter systems we have also focused very much on
having a light weight design so that the benefits of having a larger surface area are
not wasted. We have used a dome material that is up to 25% lighter than comparable
materials typically used for domes. Due to other weight reductions in the dome
assembly we have actually managed to reduce the weight up to 40% by comparison
with standard materials. Due to the low mass of the dome assembly, very fast
movements are possible – the upper limiting frequency is 27 KHz.
The tweeters have decorative aluminum
faceplates with black acoustical lenses around
the dome itself. The shape of the acoustical
lens in combination with the characteristics of
the dome has made it possible to have very
good off axis characteristics.
By using an oversized voice coil, the power
handling is increased. But it has actually been
taken further by adding low viscosity
Ferrofluid
®
round the voice coil in the voice
coil gap. Thereby thermal conductivity is
increased approximately 5 times, eliminating
spontaneous or continuous voice coil
temperature rise – the heat will be dissipated
by the magnet structure. Ferrofluid
®
is also
known as “magnetic oil”, oil filled with micro
scale magnetic particles.
Figure 3, Rear view of 28mm neodymium
tweeter for LEKTOR
®
1.
The tweeters are mounted to the cabinet without visible screws, which eliminates
diffraction and a minimalist and clean appearance.
Crossovers
The basic task of the crossovers in the LEKTOR
®
Series is to filter out frequency
content not meant to be reproduced by the driver in question. The desired result is
achieved by a unique combination of driver and crossover, for a seamless blend of
the sound from two “neighboring” drivers. The crossovers are relatively simple in
terms of the number of components (made possible by high quality, wideband driver
design). Because of “simple” filtering/short signal path, it is possible to preserve as
much of the original electrical signal as possible; preserving as much musical
information as possible (contrary to doing heavy filtering or damage control of poor
driver design, where a lot of energy is lost in the filter).
In the LEKTOR
®
Series, the unique combination of crossovers and drivers will form a
very easy impedance load as seen from the amplifier. This will make the LEKTOR
®
speakers a very good partner even with amplifiers that have limited current
capabilities. When the amplifier is gently loaded by the loudspeakers, it will perform
better – and the end result is better sound because the signal from the amplifier to
the loudspeakers is better.