Beolab 1 - tweeter

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Pattabhiraman Posted: Fri, Nov 6 2015 3:33 AM

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Hello 

Given the tweeters for Beolab 1 are now obselete/not available. Can you please suggest possible solutions for the same. I have a perennial of the tweeters.

Is the problem elsewhere resulting in the tweeter being blown frequently.

Alternatively if it is indeed the tweeter is the spare from 7-1 or beolab 8000 compatible as i guess the impedence read alike - 8 ohms.

cheers

pattabhi

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Pattabhiraman replied on Mon, Dec 7 2015 6:42 PM

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With no luck of sourcing a fresh Beolab 1 tweeter i experimented with a fresh Beolab 6000 tweeter.

While the exact geometry of  Beolab 6000 does not fit in the contour of the column it does work.

Can I please make a request to advise me on the following:

1. whether the above "jugaad" (indian term quick fix) is advisable given there is difference in the impedence (marginal though)
2. is it  likely cause any damage to the chasis - given the impedence varies between the two.- does it involve changing the values in the potentiometer
3. what are the exact impedence of beolab 6000, 8000 and beolab 1 tweeters
4. above all can i still be hopeful of sourcing a fresh Beolab 1 tweeter

Thanks very much indeed for your kind patience and look forward to collective feedback/suggestion.

Cheers

Pattabhi  

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Pattabhiraman replied on Wed, Jun 29 2016 10:05 AM

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continuing with my experiments with Beolab 1 . given the unavailability of spares i tried to recone the tweeters locally here. even that would repeatedly fail.

finally i tried my luck with a brand new 7-1 tweeter. with the impedence closing matching ~ 7 ohms i replaced it with the original tweeters and the speakers came to life. both my units currently have 7-1 tweeter.

while the screw holes do not exactly match with the orginal i made a temporary "jugaad" to secure them in the slot.

let me know if the choice of 7-1 is a good idea. 

cheers

pattabhi

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Avanark replied on Fri, Jul 1 2016 5:58 AM

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Hello,

I don't know if the tweeter of the 7-1 is any good, but maybe you can consider to repair your beolab 1 tweeter with this spare part?

http://www.sicken.ch/pi/Ersatzmembran-zu-Hochtoener-Beolab-1-B-O.html

Good luck  

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TWG replied on Fri, Jul 1 2016 10:40 AM

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The impendance of a speaker says nothing about its "acoustical compatibility". There are much more parameters that have to fit.

If you know the manufacturer, type etc. of the original Beolab 1 tweeter, you can search the internet for the parameters of the chassis. After that you can look for a comparable tweeter.

The best help can come from Mr. Geoff Martin. As far as I know he didn't design the Beolab 1 but he's one of the men with the big right knowledge at Bang & Olufsen.

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Jeff replied on Fri, Jul 1 2016 4:30 PM

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Since the BL1 is an active speaker, the impedance of the tweeter is probably one of the least important parameters as it doesn't have a traditional passive crossover, where the impedance of the drivers is a part of the design in choosing the crossover components. The amplifier won't care about impedance much if at all as long as it's not pathologically odd, but things like driver resonance, LF cutoff, and most importantly efficiency/sensitivity are important. Depending on how far above the LF cutoff of the tweeter the crossover is set, and how sharp the cutoff is, and you can do quite steep slopes with active crossovers, even the LF cutoff may not matter much as long as it's sufficiently below where the active crossover cuts off. Power handling and efficiency/sensitivity would probably be the main issues, followed by LF cutoff.

And of course if it can be fit into the hole, mounting dimensions and screw locations and such.