KEF Model 103.2 loudspeakers

Two way bookshelf loudspeaker

KEF Electronics RS Model 103.2 2-way bookshelf loudspeaker is said to use a 20 cm low-frequncy driver that is mechanically isolated from its enclosure to reduce the transference of inertial forces and thereby greatly reduce coloration caused by cabinet resonance. Electrical compensation is also used to improve efficiency and provide highpass signal filtering. Electronic overload protection is in the form of an automatic self-powered device called S-Stop, which is an acronymm for Steady static and Transient Overload protection. Because this protective device is so effective, the Model 103.2 is conservatively rated at 150 watts.

KEF 103.2 features:

Flat frequency response of direct sound

Minimum inter-unit time delay

Unique bass loading technique giving higher efficiency and greater power handling capacity than conventional systems

Electronic overload protection

Computer matching of component parts and drive units.

Sound Quality

KEF speakers are known the world over for their smooth, natural sound and capacity for reproducing fine detail. Their refined performance is due to a combination of unusual diaphragm materials, crossover design and careful assembly methods.. The Model 103.2 for instance is equipped with two drive units, both of which employ special plastic diaphragms and a computer designed dividing network. The intricate design procedures which KEF developed in the early seventies have been applied to every vital feature of the new speaker.

The resulting sound possesses a transparent airy quality which constantly dlights the ear and never causes listener fatigue. The precise matching of speaker pairs produces convincing stereo images of great depth and sharpness.

Bass Loading

Model 103.2 possesses some important new features which improve bass and lower mid range reproduction. The chassis of the 200 mm low frequency driver is mechanically isolated from its enclosure to reduce the transference of inertial forces and thereby greatly reduce colouration from cabinet resonance.

Electrical compensation is also incorporated in the dividing network to improve efficiency and provide high-pass signal filtering.

Electric Overload protection

The widespread use of high powered amplifiers has made it necessary to protect loudspeakers against accidental overload. KEF pioneered electronic overload protection for professional monitoring loudspeakers in the sixties and more recently developed a completely automatic self-powered device called S-STOP ( Steady State and Transient Overload Protection).

S-Stop is the most comprehensive, practical and effective protection circuit in use. It guards thermal overload, woofer over-swing and voltage surges. Immediately any sale limit is exceeded the input level is reduced by means of a relay-operated attenuator. Because S-STOP is so effective Model 103.2 conservatively rated at 150 watts.

Specifications

Frequency Range:  60 Hz - 20,000 Hz ±2 dB (at 2m on design axis)[-10 dB at 37 Hz and 30 kHz]

Directional Characteristics (within 1 dB of response on design axis):

Up to 20,000 Hz :  ±5° Vertically

Up to 10,000 Hz :  ±20° Horizontally

Sensitivity Level:  86 dB SPL (anechoic condition, at 1W/1m)

Maximum Output:  106 dB SPL (on programme peaks under typical listening conditions)

Distortion Second Harmonic:

20 Hz to 150 Hz :  less than 2%

150 Hz to 20 kHz :  less than 1%

Distortion Third Harmonic:

20 Hz to 50 Hz :  less than 2%

50 Hz to 20 kHz :  less than 1%

Enclosure:  10 liters

Power Handling Capacity:

Programme Rating :  150 W

Max. Continuous Sinusoidal Input :  20 V RMS, 100 Hz - 2,5 kHz 9falling to 8 V RMS from 4 kHz - 20 kHz)

Electronic protection S-STOP:  the system is protected against any continuous or intermittent fault conditions which produce input signals not greater than 60 V peak from DC to 50 kHz

Nominal Impedance:  8 Ω

Finishes:  Choice of walnut, teak, rosewood and black ash veneers with blac or brown grille fabric as appropriate.

Dimensions (W x H x D):  265  x 510 x 240 mm

Weight:  8,6 kg (19 lbs)

KEF C1 loudspeakers

 C1 Bookshelf Speaker
Compact, versatile and potent. The C1 pairs the superbly accurate 19mm (0.75in.) tweeter and 'tangerine' waveguide from the latest Q Series with a slot-ported 100mm (4in.) midrange/bass driver. Both sit on a dense two-layer front baffle system to deliver a complex, profoundly realistic and spatially accurate soundscape. With excellent power handling and a carefully tuned crossover, the C1 delivers a generously full performance that belies its discreet appearance and modest size. The front firing port makes it easy to position and the integrated wall bracket makes wall mounting a simple operation. 

Aluminium dome tweeter with 'Tangerine' waveguide
The same 19mm (0.75in.) tweeter from the latest Q Series reproduces vocals with spellbinding realism - the unique 'Tangerine' waveguide disperses its sweet natural clarity evenly throughout the room and provides excellent protection from straying fingers. 

Gold-plated terminals
The exceptional acoustic definition you experience depends on the recorded signal being perfectly transmitted, so to eliminate the risk of tarnishing, the binding posts of the C Series are gold-plated. 

Specifications
Type: Two-way bass reflex
Drive Units:
High Frequency: 19 mm (0.75") aluminium
Low Frequency: 100 mm (4")
Frequency Range: 65 Hz - 40 kHz
Crossover Frequencies: 2.5 Hz
Maximum Output: 106 dB
Amplifier Requirements: from 10 - 100 W
Sensitivity: 87 dB (2.83 V/1m)
Magnetic Shielding: Yes
Input Impedance: 8 Ohms
Dimensions (HxWxD): 260 x 150 x 221 mm (10.25 x 5.9 x 8.7 in.)
Weight: 3.2 kg (7lbs)

I like

KEF Model 104aB

Designed to be positioned vertically on a speaker stand, Model 104aB is a further development of the highly acclaimed Model 104, where "aB" was an abbreviation for "acoustic Butterworth", relating to the shape of the acoustic response of the midrange and treble drivers in the crossover region.

The new network was designed by computer and in  combination with the t27 it gives a close approach to a theoretical third order Butterworth response. A comparasion of measured and theoretical responses shows that sound output remains within ±1 dB of the ideal curve over most of the frequency range from 500 to 20,000 Hz. Likewise the phase response is very nearly perfect. KEF engineers have called the new circuit an acoustic Butterworth (aB) filter network.

The aB section has three functions:

1 - To compensate for the high frequency roll-off due to voice coil inductance.

2 - To exactly compensate for the Q and impedance of the drive unit at this fundamental response frequency.

3 - To provide terminal volts on the drive unit for a constant voltage input, which vary with frequency in such a way that the acoustical frequency response corresponds to that of a third order Butterworth high pass filter.

The effect of the modification is immediately audible as a marked reduction in colouration and is particularly beneficial in the reproduction of voices and stringed instruments.

The improvement in transient response gives increased depth perspective and much sharper imaging when reproducing stereophonic signals.

To achieve an extended frequency response from a compact cabinet without loss of efficiency. Model 104aB incorporates a 13" x 9" bass radiator acoustically coupled to an 8" bass unit. Operating in phase below 45 Hz the two units combine to offer the equivalent radiating area of a 15" bass unit. All this from an enclosure just 13' wide. This system is rated to handle 100 watts on normal musical programme and the high frequency unit is protected by a fuse against fault conditions such as switching transients and high speed spooling.

Model 104 loudspeaker systems may be upgrated to Model 104aB specification using the Model 104 modification kit which  is available from KEF dealers.

Specifications:

System:  2-way, stand-mount with passive radiator

Drive Units:

Low Frequency :  1 x B200 bass unit (Sp1039); 1 x BD139 passive radiator (SP1042)

Highh Frequency :  T27 tweeter (SP1032)

Crossover :  SP1065

Rated Max. Power:  100 watts programme

Frequency Response:  50 - 20,000 Hz ±2 dB

Nominal Impedance:  8 Ω

System Resonance:  35 Hz mechanical reflex

Dividing Frequencies:  45 Hz and 3,000 Hz

Sensitivity:  12,5 watts for 96 dB (at 1 m and 400 Hz in anechoic conditions)

Amplifier Requirements:  15- 100 watts into 8 Ω

Internal Volume:  35,5 litres

Finishes:  Walnut or Teak

Grille:  Black foam

Dimensions (H x W x D):  630 x 330 x 260 mm (24,8" x 13" x 10,2")

Weight:  16,3 kg (36 lb ) net

I like

KEF Model 103 Reference Series

With exceptional power handling for a compact loudspeaker Model 103 offers unique flexibility of installation and precise stereo image formation.

The drive units are centre-line mounted on a rotable, steel, speaker panel which can be turned (by successive right angles) through 360°. No matter how the system is positioned in the room the speaker panel may be placed to give the broadest, uniform, sound dispersion in the horizontal plane, ensuring accurate stereo imaging and the minimum of tonal variation.

Colouration

The greatest enemy of natural sound reproduction is colouration. It alters the tonal character of instrumental sounds, upsets balance and distorts acoustic perspective.

Colouration is mainly caused by uncontrolled vibrations in the drive units and the cabinet enclosure. The radiating diaphragms in KEF loudspeakers are made from highly damped plastic materials pioneered by KEF in conjunction with renowned organisations such as the BBC, the diaphragm of the low frequency unit in Model 103 is made of a specially formulated rubber-modified polystyrene laminated to a visco-elastic damping layer with a high internal loss factor. This construction effectively dissipates unwanted stored energy in the diaphragm thus preventing diaphragm colouration.

Coloruation due to cabinet wall vibration is reduced by internal bracing partitions and the use of laminated materials. Layered bituminous, anti-resonant linings effecticely cancel any remaining resonances.

Power Handling Capability

Wide range loudspeakers of compact size are necessarily inefficient and high power amplifiers make great demands on power handling capabilities if realistic sound pressure levels are to be achieved. The special motor construction of the Model 103 low frequency unit is designed fro low distortion and high heat dissipation. The anodised aluminium voice coil former and special heat resistant epoxy resin allow the coil to operate safely at temperatures up to 350°C whilst the advanced design of the magnet assembly ensures perfect magnetic linearity. Model 103 will handle the output from 100 watt amplifiers on musical programme.

Drive Units and Dividing Network

High Frequency Radiator T52 Type SP1049.

A new high frequency unit providing high power handling capabilities with exceptional transient response, wide dispersion and smooth frequency response.

Low Frequency Radiator B200 Type Sp1039.

This very special low/mid frequency unit is fitted with a coated Bextrene diaphragm and plasticised PVC cone suspension. The voice coil assembly will safely with stand short term overload to at least 350°C and continuous operation at 250°C

Dividing Network DN16 Type SP1050.

Capacitors selected to a 5% tolerance range and low hystersis ferrite cored inductors ensure close adherence to design crossover frequencies and slopes. Total harmonic distortion due to filter network is less than 0-1% at 50 watts (20V RMS)

 Environmental Adaptability

Model 103 provides broad, uniform sound dispersion for accurate stereo image formation. This is accomplished by centre-line mounting the low and high frequency unit very close together on a rigid steel panel with accurate matching of phase and amplitude between systems.

Accurate stereo image formation over the widest possible listening area also demands precise location of the loudspeaker systems. Multi-unit bookshelf systems can only provide maximum horizontal dispersion when used vertically or horizontally - but not both. When, for practical or visual considerations the systems cannot be used in the intended manner the acoustic performance will be degraded or compromises must be made.

Model 103 frees the user from these restrictions and anables positive stereo image formation whatever cabinet attitude is adopted. This is simply achieved by rotation of the steel speaker panel.

KEF engineers developed the rotatable speaker panel which permits Model 103 to be used on any of its four sides even in elevated locations

Specification:  Model 103

System Type:  Two-way, bookshelf/stand-mount

Enclosure Type:  Closed box

Input Impedance:  8 Ω

Rated Maximum Power:  100W programme

Amplifier Requirements:  25-100 watts per channel into 8 Ω

System Resonance:  58 Hz, Q=0.9

Nominal Frequency Range:  30 - 20,000 Hz 

Specific  Frequency Response:  50 - 20,000 Hz  ±2dB

Sensitivity:  25 watts into nominal 8 Ω produces 96 dB at 1 m and 400 Hz in anechoic conditions

Harmonic Distortion:  1% T.H.D. 100 - 20,000 Hz ralative to 96 dB SPL at 400 Hz, 3% T.H.D. at 50 Hz

Crossover Frequency:  3,000 Hz (electrical cut-off slope 18 dB/8ve)

Finishes:   Walnut, Teak

Grille:  black microcellularfoam

System:  SP1048

Drive units: 

B200 bass unit (SP1039),

T52 tweeter (SP1049)

Crossover:  SP1050

Internal Volume:  25,4 litres

Dimensions (W x H x D):  500 x 303 x 225 mm (19.7" x 13" x 8.9")

Weight:  19.5 kg (41,88 lb)

KEF Cantata SP1056

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)

KEF Calinda SP1053

The Calinda three-way loudspeakers are among the first KEF model to benefit from the technological innovations introduced by the Company during the early and mid 1970s - in particular the application of computer-based test methods in both design and quantity production and the use of the "Target Function Concept" in the synthesis of crossover networks. These advances have made it possible to produce loudspeakers in the domestic size and price range with a standard of performance hithero associated with professional equipment. Like most other loudspeaker, Calinda have been designed to meet aesthetic requirements imposed on them as articles of furniture, and as a result, the outward appearance shows no sign of their special technical features. 

Howev, with the grille covers removed, as shown above, certain differences in the type and positioning of the drive units, and it will also be noticed that in Calinda and largest KEF Cantata, the conventional placing of the mid-range and high-frequency units is reversed.

These features, the reason for which may not be immediately clear, are in fact part of an overall system-engineering approach, in which the various components of each model - drive units, enclosures and filter networks - are developed together and optimised to fulfil a particular need; both designs are based on practical considerations of performance and cost-effectiveness, avoiding the kind of over-specification that may look impressive on paper but is irrelevant to the listeners requirements.

 

Calinda was an 8 inch two-way system with an auxiliary (passive) radiator augmenting the low frequency response. This format was used previously in the Cadenza and Reference 104. In the Calinda system the driver layout was adjusted to allow an elegantly slim floor standing cabinet. 

Specification:  Calinda

System Type:  Two-way, floor standing

Enclosure Type:  Passive radiator

System:  SP1053

Drive Units:

Bass Unit : B200 (SP1054),

Passive Radiator :  BD139 (SP1042),

Tweeter :  T27(SP1032)

Crossover:  SP1055

Input Impedance: 8  Ω

Rated Maximum Power:  100 W programme

Amplifier Requirements:  15 - 100 watts per channel into 8 Ω

System Resonance:  28 Hz, mechanical reflex

Frequency Range:  40 - 30,000 Hz, ±3 dB

Sensitivity:  12.5 watts for 96 dB at 1 m and 400 Hz in anechoic conditions

Crossover Frequency:  3,500 Hz

Internal Volume:  45 litres

Finishes:   Walnut or Teak

Grille:  Mokka brown cloth

Dimensions (W x H x D):  700 x 280 x 350 mm (27.5" x 11" x 13.8")

Weight:  19.1 kg (42 lb)

Leggi articolo dedicato a KEF Calinda in Italiano

KEF Corelli SP1051

 Recent developments in loudspeaker engineering and new analysis techniques for evaluating acoustical performance, have resulted in KEF preparing three new loudspeaker products featuring:

Computer design filter sections of advanced specification.

Enclosures heavily damped and braced to minimise colouration

Generous power handling capabilities.

Corelli was an 8 inch two-way closed box system that built on the success of the Chorale. The developments included a new version of the B200 bass unit and an improved cabinet. 

 KEF Corelli features:

Compact shelf mounting 2-way system supplied in mirror image pairs

Generous power handling capabilities

Specification:  Corelli

System Type:  Two-way, bookshelf/stand-mount

Enclosure Type:  Closed box

System:  SP1051

Drive Units: 

Bass Unit :  B200 (SP1063),

Tweeter :  T27 (SP1032)

Crossover:   P1052

Input Impedance:  8 Ω

Rated Maximum Power:  50 W programme

Amplifier Requirements:  25 - 50 Watts into 8 Ω

System Resonance:  58 Hz, Q=1.1

Frequency Response:  50 - 30,000 Hz,  ±3 dB

Sensitivity:  19 watts for 96 dB at 1 m and 400 Hz in anechoic conditions

Crossover Frequency:  3,500 Hz

Internal Volume:  18,5 litres

Finishes:  Walnut or Teak

Grille:  Mokka brown cloth

Dimensions (W x H x D):  470 x 280 x 220 mm (18.5" x 11" x 8.6")

Weight:  9 kg (20 lb)

KEF K 120

The very first KEF compact speaker, in 1961 was the K1, a three-way baffle available in several formats. Since than, an honourable tradition of music related "C" series names has held sway. In this thirtieth anniversary year, the initial "K" returns to identify three models, each of which embodies the principles, experience, and tradition learned and earned during the past three decades.

Careful attention to both visual and acoustic design means that the "K" Series models are as easy and attractive to integrate into a home environment as they are capable of reproducing today's sometimes complex and demanding recordings in a lifelike and convincing manner.

The new K-Series models featured an attractive ‘louvred’ baffle, a quality 25mm ferro-fluid cooled tweeter, paper coned bass-midrange drive units for high sensitivity and substantial cabinets. They were carefully designed to offer an easy load to the budget amplifiers they were likely to be partnered with.

K120 (1991-93)

In the design of small loudspeakers every parameter becomes more critical. Only a'complete system' approach, as employed by KEF, is likely to bring success. Careful study of drive units, crossover and enclosure, separately and together, with their interactions, is the means to produce a musically integrated sound. KEF system design techniques have , in the K 120, produced a supremely musical small box, designed to produce its specified response when operated on a shelf, or stand mounted close to a wall.

The K 120 is a compact two-way speaker which sounds much larger than it looks. The lightweight 160 mm (6,5") bass/midrange unit provides uncoloured, fast bass response, whilst the 25 mm 91") fluid-cooled tweeter offers accurate, uncompressed high-frequency performance of exceptional clarity. A deeper-than-average cabinet gives an internal volume, and therefore a bass performance that belies its compact frontal aspect. Ideal for a first or second system, an audio-visual installation, or as satellites for a subwoofer, the K 120 is a truly outstanding miniature.

Specification: K 120

System Type:  Two-way, wall/shelf-mount

Enclosure Type:  Closed box

Nominal Impedance:  8 Ω

Amplifier Requirements:  10 - 80 W

Frequency Response:  65 Hz to 20,000 Hz [±3 dB at 2m on reference axis (-6dB at 50Hz)]

Sensitivity:  87 dB at 1m/2.83V (anechoic conditions)

Maximum Output:  107 dB [on programme peaks under typical listening conditions]

System:  SP3132

Drive units: 

Low Frequency:  bass unit B 160 (SP1283),

High Frequency:  25mm tweeter (SP1231)

Crossover:   SP2176

Dimensions (H x W x D):  340 x 205 x 246mm (13,3" x 8,1" x 9,7")

Weight:  5.6kg (12.5 lbs)

KEF K 140

The K 140 (1991-1993) was a direct descendent of the Coda II, III, IV which was a hugely successful loudspeaker both in the UK and abroad. A two-way system for use on a bookshelf or on stands, the K140 used a 200mm (8-inch) bass driver to provide good bass performance and high output capability but was compact enough to fit neatly into a wide range of listening rooms.

KEF have an enviable track record when it comes to designing classic 200 mm (8-inch) two-way systems. The K 140 is no exception. Easily accommodated, and with no special installation problems, the K 140 has a prodigious that is, for such a compact speaker.

An 18 mm (0,75-inch) thickenclosure ensures low levels of cabinet colouration, and fast, detailed bass performance, with good weight and extension, when correctly positioned. This may be on a stand around 450 mm (18-inch) high, free-standing, or with some wall reinforcement. The 89 dB/2,83V/1m sensitivity ensures high output from moderately-powered amplifiers. The use of kapton for the bass unit's voice-coil former gives high efficiency with low distortion, thanks to its freedom from magnetic effectc and eddy current losses. Being thermally inert, it is well able to withstand the high temperatures generated during high-level replay. Careful equalisation using computer optimisation together with attracyive appearance, make the K 140 the system of choice for a thoroughly musical and outstanding all-round performance.

Specification: K140

System Type:  Two-way, shelf/stand-mount

Enclosure Type:  Closed box

Nominal Impedance:  8 Ω

Amplifier Requirements:  10 - 100 W

Frequency Response:  55 Hz to 20,000 Hz ±3 dB [at 2m on reference axis (-6dB at 45Hz)]

Sensitivity:  89 dB [at 1m/2.83V (anechoic conditions)]

Maximum Output:  109 dB on programme peaks under typical listening conditions

System:  SP3133

Drive Units:

Bass Unit :  B200 (SP1284),

Tweeter :  25mm  (SP1231)

Crossover:  SP2177

Dimension (W x H x D) : 490 x 260 x 246 mm (19.3 x 10.2 x 9.7 inches)

Weight:  8.75 kg (19.25 lbs)

KEF K 160

The K160 (1991 - 1993) offered a decent increment in performance over the K140 with the addition of a passive radiator in a larger enclosure volume. A two-way system for floor standing use, designed to be positioned away from the room boundaries, it offered the traditional KEF virtues of accurate tonal balance, realistic stable stereo imaging, together with good bass extension and high output capability.

This floor-standing loudspeaker is capable of reproducing music at realistic levels, yet is very campact, talking up well under one square foot of floor space. The K 160 employs a similar bass/mid and high-frequency complement as the K 140, but with an additional 200 mm (8-inch)passive radiator to provide added bass extension and output without the need for large power input. This additional bass diaphragm is specially designed to respondquickly and accurately to the low-frequency information contained in today's recordings. KEF's computer optimisation techniques, analysing the complex interaction between bass driver, passive radiator and enclosure, result in a bass extension that extends well below 50 Hz.

The K 160 is designed to operate clear of boundaries, floor-standing, or on low stands. Of high efficiency, the K 160 has a peak output capability of a massive 110 dB. Panel dimensions have been calculated to minimise resonances, whilst keeping the front baffle as narrow as possible, so as not to impair stereo imaging. The K 160 combines plentiful, extended bass, with a clear, articulate midrange and treble. It can play exceedingly loud, when required, and will appeal to those who like high levels, but with refinement.

Specification: K160

System Type:  Two-way, floor standing

Enclosure Type:  Passive radiator

Nominal Impedance:  8 Ω

Amplifier Requirements:  10 - 150 W

Frequency Response:  48 Hz to 20,000 Hz ±3 dB [at 2m on reference axis (-6dB at 40Hz)]

Sensitivity:  89 dB [at 1m/2.83V (anechoic conditions)]

Maximum Output:  110 dB (on programme peaks under typical listening conditions)

System:  SP3134

Drive Units:

Bass  unit :  B200(SP1284),

Passive  Radiator :  BD200 (SP1289),

Tweeter :  25mm(SP1231)

Crossover:  SP2177

Dimensions (W x H x D): 750 x 260 x 246 mm (29.5 x 10.2 x 9.7 inches)

Weight:  11.8kg (26 lbs)

KEF Chorale

 Chorale (1970-79)

The Chorale paired a B200 with the established T27 tweeter in a 20 Litre closed box design, which became an instant success and KEF’s new best selling product. It combined an extended high frequency response with a natural, uncoloured midrange and a full round, bass - quiet and delicate or complex and heavy music being handled with equal ease. The success of the Chorale ensured that it remained in production until 1979.

Specification: Chorale

System type: Two-way, bookshelf/stand-mount

Enclosure type: Closed box

Size: 470 x 280 x 220 mm (18.5 x 11 x 8.7 inches)

Weight: 7.5kg (16.5lb)

Input Impedance: 8 ohms

Rated maximum power: 25W programme

Amplifier Requirements: 15-25 watts per channel into 8 ohms

System resonance: 55Hz

Frequency range: 35-40,000Hz

Finishes: Walnut, Teak, White

Grille: Brown Grey, Beige

System: SP1016

Drive units: B200 bass unit (SP1014), T27 tweeter (SP1032)

Crossover: SP1015

KEF Concerto

 Concerto (1969 - 77)

The Concerto, released in 1969, was KEF’s latest high quality three-way loudspeaker system. It maintained the KEF practice in high end systems of using a dedicated midrange driver to cover the critical vocal range, in this case the newly developed 5” bextrene coned B110. Together with the new T27 ¾” melinex domed tweeter and the established B139 bass driver, it offered full range reproduction with low distortion, high power capacity and wide dispersion.

Intended for professionals and serious enthusiasts, the Concerto became a major success and remained in production until 1977 when it was superseded by the Cantata.

Specification: Concerto

System type: Three-way, floor standing

Enclosure type: Reflex

Size: 28 x 17 x 12 inches (711 x 432 x 305 mm)

Weight: 50 lb (22.7kg)

Input impedance: 8 ohms

Power rating: 30W

Crossover frequencies: 400, 3500Hz

Frequency range: 30-30,000Hz

System: A6614

Drive units: B139 bass unit (A6171), B110 midrange unit (A6362), T27 tweeter (A6340)

Crossover: A6606

System: SP1005

Drive units: B139 bass unit (A6171), B110 midrange unit (A6362), T27 tweeter (A6340)

Crossover: SP1002

System: SP1006

Drive units: B139 bass unit (A6171), B110 midrange unit (SP1003), T27 tweeter (SP1032)

Crossover: SP1004