KEF
loudspeakers are designed to reproduce natural sound, free from exaggerated
effects of balance and with the lowest possible distortion. Many hundreds of
separate items are used to build a loudspeaker system and the electrical and
machanicl interaction of the components will significantly affect the
reproduction quality
Loudspeaker
drive units.
Every KEF
diaphragm is manufactured from plastics or, in the case of larger units, from
metal and plastics. These special constructions obviate the wide variations in
performance associated with ordinary loudspeakers, and considerably reduce
colaoration due to the absence of unwanted resonances in the diaphragm itself.
KEF
engineers work with radically new techniques to explore the truth about sound
coloration, its causes and prevention. Computer based analysis techniques
unfold a more precise and detailed insight into speaker behaviour than was
previously possible using conventional research techniques.
To make
loudspeaker systems which optimise the performance of individual KEF drive
units, recent research has concentrated on the interaction of other critical
components with the drive units - the dividing network and the enclosure.
Loudspeaker
Enclosures
Resonances
in a loudspeaker enclosure are known to cause unwanted acoustic radiation which
can ruin the clarity of sound from even the finest drive units. The impulse
response compares signals from a single drive unit measured in a simple
undamped enclosure and from the same unit in a box to which optimum dampinghas
been applied using layers of bituminous damping material.
Enclosure
analysis is part of loudspeaker engineering. KEF are noe able to assess
objectively the audible effect of enclosure resonances and consequently, each
KEF system is critically and consistently damped to minimise resonances and
reduce audible coloration.
Dividing
Networks
Conventional
filter designs assume that the load is a simple resistance, whereas in fact,
loudspeakers present complicated loads with frequency dependent impedance
characteristics. As a result, traditional loudspeaker dividing networks rarely
satisfy the conflicting requirements of smooth amplitude frequency response and
desirable impedance characteristics.
An entirely
new approach to dividing networks has been developed by KEF. The new technique
improves transient behaviour giving a smoother, more transparent sound quality,
increased depth perspective, and sharper stereo imaging.
System Study
Detailed
objective analysis of the comleted loudspeaker system is aided by another
sophisticated KEF computer programme. Three-dimensional plots of cumulative
spectra - provide "in depth" displays of speaker response in terms of
amplitude, frequency and time. At last it is possible to see the effects of
speaker design changes and relate them to sound quality.
Quality
assurance
The quality
of a KEF speaker is under surveillance and control at all stages of production,
commencing with the critical inspection of incoming raw materials and
components. Frequent inspection of subassemblies at many subsequent stage
ensures a very high standard of consistency and reliability. Final testing is
carried out using the most sophisticated techniques. Stringent and effective
quality controls enable KEF to offer a Five year warranty on all its products.
Specification: Cantata
System
Type: Three-way, floor standing
Enclosure
Type: Closed box
System: SP1056
Drive
Units:
Bass Unit
: B139 (SP1044),
Bass Unit :
B110 (SP1057),
Tweeter
: T52 (SP1049)
Crossover: SP1058 and SP1064
Input
Impedance: 8 Ω
Rated
Maximum Power: 150 W programme
Amplifier
Requirements: 15 - 150 watts per channel
into 8 Ω
System
Resonance: 38 Hz, Q=0.7
Frequency
Range: 35 - 20,000 Hz, ±3 dB
Sensitivity: 8 watts for 96 dB at 1 m and 400 Hz in
anechoic conditions
Crossover
Frequencies: 250 and 3000 Hz
Internal
Volume: 60 litres
Finishes: Walnut or Teak
Grille: Mokka brown cloth
Dimensions
(W x H x D): 815 x 340 x 392 mm (32.1" x 13.4" x 15.4")
Weight: 31.7 kg (70 lb)