SpeakerTalk

Andreas · Posted: Wed Jan 18, 2006 11:19 pm Post subject: Novice project for old 104ab's

Up front I'll tell you I am new to this!
Could somebody please tell me if it is possible to convert a pair of tired cabinet 104ab's into something like the JR149, but perhaps using stone pipe instead of the folded aluminium case that Rogers used?
I see that there are different versions of the B110 speakers, would mine be the right ones?
There is a guy on Ebay selling 'improved' crossovers for the JR149 and I was hoping to get a pair for the project but I don't know.
I would also like to make a matching (shaped) subwoofer for them - any suggestions for that would be appreciated.
Thanks for any help.
Andreas.

Stuart Booth · Posted: Wed Jan 18, 2006 11:26 pm Post subject: Novice project - 104aB

My 104aB's have 8" B200 and not the 4.5" B110

Please check again.

Regards

Stu.
_________________
Stu.

Andreas · Posted: Thu Jan 19, 2006 8:07 am Post subject:

Whoops! you're right - I said I was new to this, perhaps I should have said I was stupid too Smile

.

I will try get hold of some B110's from somewhere I hope, do you have any suggestions about where and are there different versions that I should avoid/try to get?

Thanks Stu.

proffski · Posted: Thu Jan 19, 2006 7:55 pm Post subject:

I have detailed plans for a JR149 type loudspeaker using concrete flue pipe.

It was published by Dalesford as 'System 8' using Dalesford D30/110 and Isophon KK10/8 tweeter.
The volume is about the same as required by a KEF B110.
It was first published by R.F.C. Stephens as "The Round Sound" then by 'Popular Hi-Fi" in 1978.
The kit was made available by Wilmslow Audio.

Looks quite easy but labour intensive!
The structure is about 35cm high and 25cm diameter external dimensions.

Andreas · Posted: Thu Jan 19, 2006 8:28 pm Post subject:

Sounds interesting! Are the drive units still available? What was the opinion of the sound quality?
Can you attach it to an email to me?
I am a good carpenter and enjoy projects such as this, but I don't feel too inclined to spend the time and money if they are not going to be as good as LS3/5A's or JR149's.
Thanks for your interest.
Andreas

proffski · Posted: Thu Jan 19, 2006 10:01 pm Post subject:

If you can find the units in good condition I'd go for KEF.
There is a little carpentry in the top and bottom of the pipe as well as the baffle, the rest is cutting the concrete pipe...
I see no reason that if built properly they should not sound absolutely brilliant.
In its favour you have the shape and the non resonant nature of the concrete cabinet!

There are other units which you could use instead of the B110 & T27.
I'd ask Colin and Terry nicely about possible equivalents, they are the experts here as is the Loudspeaker Guru!
I guess by not using the KEF originals you fall outside the remit of this fabulous site.

It is said that the 'Monacor' SPH135/AD is a good replacement for the KEF B110, the Seas H831 or possibly H457 in place of the KEF T27.

I'm sure the others may well give you other alternatives...

The book is in a folded concertina type format, so would be difficult to scan and my computer scanner is still busted.
I could photo-copy it maybe and send it to you via Par-Avion if you wish.
I'd of course need your address sent to me in email or the handy PM service this site offers to keep it confidential.

Andreas · Posted: Thu Jan 19, 2006 10:17 pm Post subject:

Sounds ab fab. I'll email you my address. I am hopefull to find a pair of 110's and T27's though. I can't understand why Kef discontinued them.

Another scenario for my tired looking but good sounding 104aB's would be to rebuild them into concerete pipes with the bass radiator pointing downwards to reduce the frontal area for aesthetics? Ever heard of anything like this before Proffski?

Thanks for your help.

Andreas.

proffski · Posted: Thu Jan 19, 2006 10:32 pm Post subject:

I do not understand where you are getting the B110 from.
The 104aB did not use B110s. Shocked

It used one of KEFs B200 series, the T27 and the B139B Auxilary Bass Radiator. Not a B110 in sight... Confused

proffski · Posted: Thu Jan 19, 2006 10:34 pm Post subject:

You could mount the ABR in the vertical position to narrow the frontal area...

Andreas · Posted: Thu Jan 19, 2006 10:36 pm Post subject:

Sure, I accept that; it was a blunder in my first posting. Can't the 104aB's be recycled into larger pipes with the bass radiator facing down?
Andreas.

proffski · Posted: Thu Jan 19, 2006 10:42 pm Post subject:

I do not see why not, but please wait till you get the posting.
I cant see why you could not upscale the design, good luck!
Remember you will end up with a very heavy cabinet! Smile

Andreas · Posted: Thu Jan 19, 2006 10:48 pm Post subject:

I would have just kept the volume the same as I'm no designer. Do you think it is ok to just use bigger pipe then?

proffski · Posted: Thu Jan 19, 2006 11:55 pm Post subject:

Other KEF speakers with the same units used slightly higher internal volume.
Probably give you a bit more bass but upto a limit.
I may run my design software sometime and get some graphs...

Again, I'm sure the guys with more experience may hold the answers.
There are a lot of things to consider.

Andreas · Posted: Fri Jan 20, 2006 9:56 pm Post subject:

Hi again Proffski,
I have been offered a very bad (cabinets) condition pair of concerto's. Would these be a good source of drive units for the JR149/LS3/5A project?
Much as it hurts to break them, I can always refinish the original cabinets if I can't get what I want from the pipes.
I have read somewhere that the names 'T27' and 'B110' are not all there is to it; would the concerto loudspeakers yield exactly the right type of drive units that I need for the LS3/5A/JR149 project?
Thanks for your help once more.

proffski · Posted: Fri Jan 20, 2006 10:34 pm Post subject:

Indeed, the Concerto used T27 tweeter and B110.
I am not sure if the Concerto's used the units without changes throughout their production life.
Certainly the bass B139 did evolve...
What are the SP numbers on the back of the units?

Perhaps others on this site may be of greater help here?