Celestion SL-6 Celestion SL-6 Bookshelf Speaker Pair (Copper Tweeters)

Celestion SL-6 bookshelf speaker pair with copper tweeters. In outstanding functional condition. Cosmetic condition is also good with minor stain on top of wood and a loose portion fabric on one grille. An excellent vintage UK speaker that will make a discerning user very happy. I have not sold much on Audiogon but have a 100% rating on eBay: http://www.ebay.com/usr/jonasblank

Local pickup in NY/NJ/CT only. I can drive it to you if mutually convenient.

Specifications :
Power Handling................................35-100 Watts RMS Frequency Response........................45Hz - 20kHz
Sensitivity........................................84dB
Impedance.......................................8 Ohms
Dimensions(w x d x h)......................20 x 25.5 x 37 cm Weight............................................9kg per side
Made in...........................................UK, England

More from hifinews UK:
"Launched at the Harrogate Hi-Fi Show in 1981, the Celestion SL6 looked different, and it was more different than it looked. In essence, its all-new drive units had been designed with the help of Celestion’s then-unique and revolutionary laser-based vibration analysis measurement system. It was the first British speaker to use a metal-dome tweeter, but the bass unit was equally innovative.
The laser analysis system used could scan the surface of a driver diaphragm, and produce still or animated images to show how the diaphragm was actually behaving. It was now easy to see whether it was vibrating evenly in response to an input signal, or whether it was ‘breaking up’, with different parts of the surface going their own way.

This made it possible to produce drivers that behaved in true pistonic fashion within their operating ranges, and to eliminate problems caused by some constructional aspects in conventional cone drive units. For example, the usual glued-on dustcap was found to cause breakup modes, as did the usual type of bonded surround.

So in the SL6’s bass unit, the dustcap was dispensed with and the concave centre was made as part of the 165mm ‘vinyl homopolymer’ cone. The surround was made of compatible material and welded to the cone, with almost no increase of thickness at the joint. Attention was also paid to the effects of the leadout wires from the voice-coil.

In Celestion’s metal-dome tweeter, the curved diaphragm and voice-coil former were made in one piece, the coil former being a cylindrical continuation of the domed top. Copper was chosen mainly for good heat dissipation. This moving element was made by electroforming, and was only 32 microns thick, but even so its mass was such that the upper resonance was only just above 20kHz. A notch filter was added to remove this resonant peak from the response, and in production each filter was individually tweaked to the correct frequency for that specific tweeter.

For the cabinet, the team wanted the enclosure to be as rigid and light as possible. Rejecting Aerolam as too expensive, the SL6 was clothed in a sealed-box cabinet instead. This was made of 19mm veneered particle board, strengthened by internal fillets at the corners and with damping material on all the panels. Inside was a loose filling of BAF wadding.