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 Uni-Q Driver


 A New Direction In Sound
The "Q" Factor  - or why speakers sound different in different rooms.
The Uni-Q principle, developed by KEF engineers, realises the long-held ambition of loudspeaker designerd to create the drive unit where all the sound radiates from a single source.
"Q" is the measure of a loudspeaker's directivity - how it bearns its sound towards the listener. It is this factor which very largely determines how a loudspeaker will sound in any given room.
When we listen to live music we hear each instrument, a trumpet, say, from one discrete point in space, together with a proportion of the sound reflected from around the hall or room.
With reproduced sound however, a single drive unit does not exist which peroduce the entire audible spectrum. Most loudspeakers employ two or more drive units, separated from each other. So now different parts of the trumpet come from two different locations - and at slightly different times.


 Because the directivities of the two units do not match at crossover, the sound is different at different listening positions. The tonal balance shifts as the listener moves. Sit off-centre and the trumpet becomes muted, the singer catches a cold.  Listeners in different posiitions, or indifferent roomscan heara coloure and out-of-focus soundstage.

Using Neodymium-Iron-Born, a newly developed magnetic alloy which has ten times the energy product of conventional ferrite, KEF designers have engineered a tweeter assembly small enough to be located in the neck of the bass unit's cone, precisely  at the point where the sound sources, the acoustic centres, of the two units coincide.
The direct and refflected path-lengths from both units to the listener's ear are now the same. Correct phase relationships ensure that high and low frequencies add up correctly to produce the desired response.



With Uni-Q, not only has KEF placed the woofer and tweeter on the same axis, their acoustic centres are also in the same plane. The directivity of both units is identical. The trumpet is back in one piece, unmuted and the singer's centrestage, in perfect health.
The unification of woofer and tweeter "Q" lies behind the revolutionary unit's name _the KEF Uni-Q Driver. More accurate sound in more locations, and from more listening positions is the keynote of Uni-Q.

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