KEF 103/4 Drivers B160, recone

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Hi - the tweeters and mids are sounding fine - and I have spare backup tweeters from an old pair of Q80s if I need them.

Would force cancellation pose an issue if I were to replace the bass drivers? I am starting to think that may be the only option. I have found the specs for the B160, I have found some that come close in terms of fs, but wondering how important the Vas rating is, as these numbers arent really coming close with potential new drivers.

KEF B 160 / 8 Ohm

8 Ohm
50 W
woofer

thiele-small data:

Re 7.4 Ohms
Le 0.61 mH
fs 40 Hz
Qms 5.45
Qts 0.30
Qts (8Ohm) 0.33
Sd 131 cm3
Vas 42 Liter
Cms 1.75 mm/N
Mms 9 g
B*l 7.3 N/A
SPL 91
 
No problem the steel rod just takes the force cancellation from 97% to 99%. Or something. Find budget drivers that are really close to the parameters of the originals and enjoy. You will need to extend the wires from the crossover to the drivers, btw.
Pretty sure you need the dcr, inductance, vas, and sensitivity to be close to the original.
 
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The closest driver that I can find (where the cost is also right) is this one. Any thoughts on this?

Visaton W170S-8 6.5" Woofer with Treated Paper Cone 8 Ohm

The Vas is close, the resonant freq is close, the only issue is the spl is 86db, compared to the former 91. This is disappointing but its been very difficultly trying to find a driver with close vas.

If Im bi-amping too, this shoudnt affect things too much, I'll just have to turn the bass drivers up louder than the top end.
 
Wow, I didn't expect this old thread would still be alive! This was 14 years ago but I still have those speakers and my re-coned drivers are still running great.
I would suggest sending original drivers to the shop if at all possible. Mine were really shot and at the time donut seals (inner seals in lieu of dust-caps) were no available. I was told any competent shop should be able to re-cone those with generic kit as the sizes used were standard, both for voice-coils and cones.
I was going to recommend Orange County Speakers for parts but it seems they are closed as repair shop. Orange County Speaker Repair is now GLS Audio
However they recommend they old Tech for repairs so you might want to try to contact him for parts.
The other place having all the parts was somewhere in upstate NY (or close). I can't remember the name but I spoke to the owner regarding re-coning KEF 105.2 12 bass driver - he had the parts. You might want to google it through AudiKarma.org.

One, thing: KEF Reference One are development speakers from 103/4 so you might want to search for those drivers as they should fit into yours. Or search for replacement drivers on Ebay - these do show up every now or then...
Your 103/4 are worth repairing into original condition.
Good luck.
 
Cheers TR6man. I may be onto a solution, and it doesnt involve the original drivers at all.

THANKS KEF FOR ALL YOUR HELP!! (thats sarcastic BTW).

Thanks to the absolutely marvellous folk at Madisound I may have found a solution. I cant recommend them enough. I will keep you posted.
 
Wow - after a ton of mucking around - including emailing KEF UK (no reply at all) and KEF USA (stock "we dont have that part" reply....yes but all I wanted was the datasheet - dummies!), I then looked into reconing - Simply Speakers had a recone kit at $35 each however werent able to advise if the recone kit would mean that the reconed speaker had the same specs as the original B160 driver - so that option was out. That was the only recone kit I could find anywhere - however with totally no specs.

I was then resigned to thinking I'd have to replace the drivers with another driver - and yes, that would mean losing the coupling pole between the 2 drivers in each speaker. I emailed on a ton of other speaker forums and got some useful advice from a former KEF engineer - that the most critical specs to try to match in a cabinet design like this were moving mass and Vas. I also heard from another coot on a forum who recommended using $200US drivers (I would need 4!) and when I baulked, he said that any other driver would be "rubbish."

Wow.

I emailed around and Madisound were incredibly helpful. Brain advised me that if I got him the specs of my 4th order bandpass cabinet, he could model some drivers in there. So I wasnt too hopeful but they did some modelling in a Bass Box programme. They came up with this driver:

Peerless 830657 6.5" SDS Woofer

And the price was close to US$20 each! So pretty happy with that (but terrified that these new drivers wouldnt work) I ordered them and they arrived in NZ about 5 days later.

The circumference on two side were a bit bigger than the former drivers, however they just needed a bit of sticky foam put around the front, and after a bit of filing on the 2 longer sides of each driver, I could put them in the cabinet. I screwed them in and tested them out - they sound great and I have a ton of tight bass. Very Pleased - despite the fact there is probably a bit more cabinet resonance now without the coupling pole. The only real issue is that they are about 2dB less sensitive than the old drivers, so my only option really is to bia-amp (which was my plan anyway).

Its really annoying that I wasnt able to hear these speakers with the old drivers - I will never know if these new drivers are a bit step up, or down.

If anyone has blown woofers in their 103.4's, use these drivers. If these drivers are NLA, then Im sure Madisound would be happy to help you find another one.

Vedran Im not sure how to answer your question. The subs that I got worked for the bass portion of my cabinet - you need a front/firing woofer/mid for your units?
 
Hi, slimecity
You've just answered my question, about replacement drivers. My intention is to convert 103/3, which has sub as dual chamber, one driver bandpass to some sort of 103/4 which has triple chamber, two drivers in push-pull bandpass subwoofer section. That means different box construction and that is not problem. Front drivers, B160 and T33 are Ok but the old box and internal drivers are not. Thank you for info.
Vedran
 
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