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Early model Cadenzas - pictures & questions

 
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SpiderJon
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Joined: 16 Oct 2006
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PostPosted: Wed Oct 18, 2006 12:21 am    Post subject: Early model Cadenzas - pictures & questions Reply with quote

I've just acquired some early model Cadenzas - serial numbers 9514 & 9589, 'inspection' date March 1972 - and have put some photos of them online at

http://picasaweb.google.com/jon.wallis/KefCadenzas

I'm especially curious about the rather DIY-looking construction of the ABR. Based on information on this site, if it's an early model, the ABR would have had a foam surround, but mine are definitely rubber (and still in good condition).

So I'm thinking it's a later "repair", particularly given the way it's fitted - ie, just bolted over the cut-out hole, with gaps at the side (although, the gaps might be there for airflow through the holes in the side of the polystyrene block - but why?).

Also, the ABR 'unit' - ie, the thing shown in

http://picasaweb.google.com/jon.wallis/KefCadenzas/photo#4986535201053278226

- is the same on both sides - ie, there's an identical diaphragm on each side - is that "normal"?

Finally (for now) - are Cadenzas all built in the same orientation - ie, with the Tweeter above left of the Woofer - or were they sold in "mirror-image" pairs?

Any info gratefully received!

Regards

Jon
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speakerguru
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Joined: 18 Nov 2005
Posts: 958
Location: Green Hut, Tovil

PostPosted: Wed Oct 18, 2006 12:40 pm    Post subject: Reply with quote

This was before my time at KEF but I do recall a few things about these early passive radiators (PR) as they were described to me.

The Cadenza was probably the first PR system brought to KEF by the then new Technical Director, Laurie Fincham, who had previously designed a whole range of PR systems while at Celestion.

These early PRs were cut from a single block of material and a surround added to each sides. Simple, cheap and effective, however the later conventional chassis built units more easily fitted in with line building techniques, the moving mass could be changed more easily by using different metal tubes and sealing to the cabinet was more reliable, so, they were eventually superceded.

The hole is simply to equalise air pressures. Otherwise the trapped air between the surrounds would cause surround distortion at high excursions.

SG
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ColinR
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Joined: 31 Jul 2004
Posts: 1175
Location: Staffordshire

PostPosted: Wed Oct 18, 2006 7:37 pm    Post subject: Reply with quote

As SG says the ABR units are completly kosher, early but not rare.

The Cadenza, Concerto, Chorale, Coda, Ref 104, etc were never "handed" as it would have slowed down production and testing.
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