What is stereo?

There are now two system of high fidelity, monophonic (monaural) and stereophonic. Monophonic is a system that starts from one microphone and is fed through a single high fidelity set. Stereophonic is a double system. Two separate microphones are placed at different sides of the orchestra and two different systems are used to keep the two signals or channels separated. Two separate speakers are used, placed on different sides of you room. Stereo is much like 3-D photography, two slightly different sound reach your ears giving you a new dimension in sound.

H.H. Scott '59

KEF Chorale Mk III (1983)

 Chorale III is a very compact 2-way bookshelf loudspeaker which, despite its being unobtrusive, nevertheless produces the full-bodied detailed sound quality associated with larger KEF loudspeakers. Styling is simple and uncluttered with front baffle graphics for those who prefer to listen with the grille removed.
Efficiency is in the medium to high range at 87 dB/W/m and the output from a 60 W amplifier can be handled safely under audiophile conditions.
The design of small loudspeakers is actually more difficult than for larger models. Every parameter is more critical and only a "complete system" approach is likely to be successful. The performance of each component must be studied first in isolation and then in relation to the others because drive units, dividing network and enclosure all react together to produce a musically integrated sound.
Through careful optimisation of drive unit parameters effective bass output extends below 50 Hz which is more than adequate for domestic applications. Low frequency  characteristics have been determined so that natural sound balance will be obtained when the loudspeaker is placed with its back to a wall.

 KEF system design techniques are completely vindicated by Chorale III. Computer optimisation programmes, listening tests and production quality control combine to produce a loudspeaker which offers astonishing performance in relation to its size and price.
Cabinet work is finished in top quality simulated walnut with brown textile grille.

KEF Chorale III is perfectly suitable to reproduce compact disc and other types of digital recording with full dynamic range.

 The unobtrusive appearance of Chorale III belies the tight, integrated sound which comes from this small box. The carefull integration of bass and high frequency performance is achieved through a deceptively simple 7 element dividing network, skilfully designed using computer techniques.
The bass/midrange unit is fitted with a magnet system much larger than that frequently found in speakers of this size and price, thus affording the degree of control necessary to avoid "boom" in a speaker which is likely to be used on a shelf or close to a wall.
This deive unit has a nominal diameter of 160 mm, with a plastics coated fibre pulp cone and PVC roll surround. The ywo-layer 25 mm voice coil is bonded with high temperature resins to reduce risk of burnout.
With a nominal diameter of 30 mm, the impregnated textile dome high frequency unit is driven by a two-layer voice coil 25 mm in diameter. The air gap is filled with a special Ferrofluid which, by keeping operating temperatures lower, reduces variations in high frequency level at high volume caused by temperature related compression effects.

 The cabinet is constructed from high density chipboard, providing bass loading with 9,4 litres of air in a sealed enclosure. Drive unit and cabinet parameters are carefully matched to optimise low frequency performance.
Chorale III is finished in simulated walnut high quality PVC foil with the grille board covered in a brown knitted textile.

Specification: Chorale III
System Type:  Two-way, bookshelf/stand-mount
System  SP3021 Drive units: 
B160 bass unit (SP1094),
T33 tweeter (SP1089)
Crossover: SP2029
System  SP3022 Drive units:
B160 bass unit (SP1095),
T33 tweeter (SP1089)
Crossover: SP2030
Nominal Impedance:  8 ohms
Rated Maximum Power:  50 W
Directional Characteristics (within 2dB of response on reference axis)
 Vertically : up to 20 kHz for ±5°
 Horizontaly : up to 12 kHz for ±20°
Frequency response:  79 Hz to 20,000 Hz,  ±3.0 dB at 2m on design axis
Sensitivity:  87dB spl at 1m on reference axis for pink noise input of 1W
Distortion (Measured at 1m on reference axis at mean spl of 90dB, anechoic conditions)
Second harmonic : less than 1% from 170Hz to 20,000 Hz
Third harmonic : less than 1% from 80 Hz to 20,000 Hz
Maximum output:  105 dB on programme peaks under typical listening conditions
Enclosure Type:  Closed box
Internal Volume:  9,4 litres
Finish: Simulated Walnut Veneer
Grille: Brown fabric
Dimensions (H x W x D):  370 x 220 x 180 mm (14.5 x 8.7 x 7.1 inches)
Weight:  4.7kg (10.4 lb)

Nessun commento:

Posta un commento