Dad was a stickler for audio quality so I am assuming they are/were pretty good. I'd like some help from the forum in the following ways...
Please would you suggest a way to get started building the speakers. I am a physics student so dont have problems with the maths but I havent done much practical cabinet work before so the simpler the better.
In your opinion, knowing how difficult speaker design is and considering the quality of my drivers, can I build a pair of speakers worth the investment of time?
Do you know of any tried and tested standard designs with easy to follow guides... i assume these drivers were part of a DIY kit originally.
Thanks in advance for any help! I'm excited to hear your opinions.
Please would you suggest a way to get started building the speakers. I am a physics student so dont have problems with the maths but I havent done much practical cabinet work before so the simpler the better.
In your opinion, knowing how difficult speaker design is and considering the quality of my drivers, can I build a pair of speakers worth the investment of time?
Do you know of any tried and tested standard designs with easy to follow guides... i assume these drivers were part of a DIY kit originally.
Thanks in advance for any help! I'm excited to hear your opinions.
Old Kef's are getting towards classic status so worth doing something with them
There is a specialist forum:
http://www.hifiloudspeakers.info/public_html/index.php
and falcon acoustics sell cross-overs for many of the Kef speaker combinations
But as Cal says more details would be helpful
There is a specialist forum:
http://www.hifiloudspeakers.info/public_html/index.php
and falcon acoustics sell cross-overs for many of the Kef speaker combinations
But as Cal says more details would be helpful
Ah, the classic KEF drive unit combination!
Send me an email via the button below and I will forward the original KEF DIY enclosure designs for these drive units. The construction sheets also give the recommended crossovers but, as mentioned earlier in the thread, suitable crossovers can be obtained from:
http://www.falcon-acoustics.co.uk/
There are other designs around that use these particular drive units in a transmission line enclosure.
If you want datasheets for the drive units then I can send you these as well.
Geoff
Send me an email via the button below and I will forward the original KEF DIY enclosure designs for these drive units. The construction sheets also give the recommended crossovers but, as mentioned earlier in the thread, suitable crossovers can be obtained from:
http://www.falcon-acoustics.co.uk/
There are other designs around that use these particular drive units in a transmission line enclosure.
If you want datasheets for the drive units then I can send you these as well.
Geoff
Scottmoose said:You thinking IMF there Geoff?
I can feel the bass already.
Actually, I was thinking of the Chris Roger's 'R50' equivalent published in Hi-Fi Answers back in August '73. Then of course there is Chris Roger's other design, the PRO-9TL. This originally used different mid and treble drive units but it could be adapted to be all KEF.
I still have a rather tatty drawing for another transmission line design that used the B139, B110, 2 x Celestion HF1300, T27 and an STC (Coles) 4001K super tweeter, but I forget what this design was called now.
the state of the art has progressed since the Pro9-TL article was written - http://www.tech-diy.com/pro9.htm
the B139 has a very powerful motor (BL=12.3), low resonant frequency, Qt of 0.37, Re of 6.2 or so, but will only handle 100 watts -- if you do manage to fry the voice coil it is easily dissembled and rebuilt.
the B139 has a very powerful motor (BL=12.3), low resonant frequency, Qt of 0.37, Re of 6.2 or so, but will only handle 100 watts -- if you do manage to fry the voice coil it is easily dissembled and rebuilt.
edwardowen2 said:
Hi,
The quality of loudspeaker design has moved on substantially
since the heyday of Kef kits, as has the quality of drive units
available to the constructor.
TBH you should sell the drivers to someone who seriously
wants to build one of the older designs, you should only
build one of these designs if you are seriously keen on
retro stuff, because whilst they are not that bad, they
are not that good either.
Some of the designs for the drivers are distinctly poor, I'd go
as far as saying oversimplifying to the extent of being wrong.
Original KEF drivers in good condition fetch a very good price.
You could then buy a very good second-hand pair of speakers
or choose a specific design suitable for your current purposes.
See how much you can get for the drivers and consider that
biulding something like this http://www.zaphaudio.com/audio-speaker12.html
and adding a subwoofer will not only be far easier than the
KEF TL designs, it will also sound much better (as long as you
do a good job on the mechanical behaviour of the cabinet.)
/sreten.They are new and completely unused, just another project dad never got round to. I seem to remember him saying he would make them into speakers made out of an old concrete sewer pipe. Having read up a bit i realise that isn't quite as ridiculous as it originallly sounded.
I would not be willing to sell them because I would like to finish the project my dad started; however how much would they be worth? Are they a well known and well respected combination of drivers. Would it be true to say the tweeters have stood up worst to the test of time and advancement of technology? should I consider replacing them?
I would not be willing to sell them because I would like to finish the project my dad started; however how much would they be worth? Are they a well known and well respected combination of drivers. Would it be true to say the tweeters have stood up worst to the test of time and advancement of technology? should I consider replacing them?
Hi,
No. The tweeters are fine. Replacing them would mean you've
already started to contradict yourself. The main problem is the
B110 midrange, it has a somewhat variable mid-band peak
that is difficult to equalise without taking measurements.
Do a search on e-bay, a pristine set of the six classic 3-way
drivers presumably all made at the same time so the units
should match somewhat is worth quite a lot of money.
As I've said, most of the designs available for those drivers
are not very good. Theorectically the best way of using the
drivers in my opinion is to build a pair of LS3/5a clones* and
use the B139's for a powered isobaric subwoofer.
The sewer pipe is not a bad idea, but presents considerable
constructional difficulties, not recommended for a novice,
and even if built a suitable crossover is not available.
/sreten.
* equalising the midrange peak must be done, either by ear
or measurement, you can't simply use a crossover design.
No. The tweeters are fine. Replacing them would mean you've
already started to contradict yourself. The main problem is the
B110 midrange, it has a somewhat variable mid-band peak
that is difficult to equalise without taking measurements.
Do a search on e-bay, a pristine set of the six classic 3-way
drivers presumably all made at the same time so the units
should match somewhat is worth quite a lot of money.
As I've said, most of the designs available for those drivers
are not very good. Theorectically the best way of using the
drivers in my opinion is to build a pair of LS3/5a clones* and
use the B139's for a powered isobaric subwoofer.
The sewer pipe is not a bad idea, but presents considerable
constructional difficulties, not recommended for a novice,
and even if built a suitable crossover is not available.
/sreten.* equalising the midrange peak must be done, either by ear
or measurement, you can't simply use a crossover design.
Yes, the B110 is the weakness. However, the B139 in the Chris Rogers Hi-Fi Answers transmission line produced bass of a quality that is still hard to beat.
If you are determined to use these drivers yourself rather than selling them to buy more modern, better drivers, then one way forward would be to build the Hi-Fi Answers enclosures, buy a decent quality six channel A/V amplifier with volume control, and precede it with an active crossover like the Behringer DCX2496. This would have the advantage of extreme flexibility and would allow you to correct the B110's problems easily. Further, with the addition of suitable software and a cheap omnidirectional electret microphone capsule, a computer with soundcard can be turned into a cheap but very effective loudspeaker measurement system, allowing you to set the crossover precisely. Although this sounds complex, it's easier than you might think and would certainly be easier than attempting to persuade a passive crossover to sound right.
If you are determined to use these drivers yourself rather than selling them to buy more modern, better drivers, then one way forward would be to build the Hi-Fi Answers enclosures, buy a decent quality six channel A/V amplifier with volume control, and precede it with an active crossover like the Behringer DCX2496. This would have the advantage of extreme flexibility and would allow you to correct the B110's problems easily. Further, with the addition of suitable software and a cheap omnidirectional electret microphone capsule, a computer with soundcard can be turned into a cheap but very effective loudspeaker measurement system, allowing you to set the crossover precisely. Although this sounds complex, it's easier than you might think and would certainly be easier than attempting to persuade a passive crossover to sound right.
http://www.linkwitzlab.com/sb80-3wy.zip
For full details of linkwitz's design. Though note he simply assumes
the B110 has a flat response, which it doesn't, and he uses 4th
order electrical not acoustical croosover slopes, not that hot.
/sreten.
For full details of linkwitz's design. Though note he simply assumes
the B110 has a flat response, which it doesn't, and he uses 4th
order electrical not acoustical croosover slopes, not that hot.
/sreten.
using the KEF drivers...
I think most are missing the point here.
edwardowen2:
Dad was a stickler for audio quality
If I am reading correctly, this implies that his da is no longer among the living.
The appeal , al least what I read into this , is to use the drivers in a manner that his father would have desired and as a tribute. Perhaps a LS3/5 clone or said concrete pipe enclosure could be done.
Rather than try to persuade edwardowen2 to do something else, maybe absolute encouragement should be given to him so that he may finish a project that his dad was obviously wanting to do.
I think most are missing the point here.
edwardowen2:
Dad was a stickler for audio quality
If I am reading correctly, this implies that his da is no longer among the living.
The appeal , al least what I read into this , is to use the drivers in a manner that his father would have desired and as a tribute. Perhaps a LS3/5 clone or said concrete pipe enclosure could be done.
Rather than try to persuade edwardowen2 to do something else, maybe absolute encouragement should be given to him so that he may finish a project that his dad was obviously wanting to do.
Thanks everyone for your replies, this is clearly a forum packed full of intelligent and knowledgeable people.
Nanook you are right in thinking I'd treat the project as a tribute to my father, or rather a process through which to remember him. What a bizarre grieving ritual! I could build the speakers that he would have built. However I'm sure he'd say "sell the drivers and make the best that you can".What I'm thinking at the moment is to use the concrete pipe design, but using modern drivers and analysis equipment: essentially the same project brought right up to date. So I think I will sell the drivers (contrary to what I said in a previous post) and use the money to start the updated design.
Any tips on how to effectively advertise them? What is a reasonable reserve price on ebay for the set?
Thanks sreten, EC8010, jackinnj, salas, nanook, consort and geoff
Nanook you are right in thinking I'd treat the project as a tribute to my father, or rather a process through which to remember him. What a bizarre grieving ritual! I could build the speakers that he would have built. However I'm sure he'd say "sell the drivers and make the best that you can".What I'm thinking at the moment is to use the concrete pipe design, but using modern drivers and analysis equipment: essentially the same project brought right up to date. So I think I will sell the drivers (contrary to what I said in a previous post) and use the money to start the updated design.
Any tips on how to effectively advertise them? What is a reasonable reserve price on ebay for the set?
Thanks sreten, EC8010, jackinnj, salas, nanook, consort and geoff
Those are the ones I made, when the same set of drivers (and XO's) were given to me about 2 years ago.salas said:
Not perfect, but a significant improvement over my old pair of jamo cardboard speakers.
I like them, there's room for improvement, but I'll start a another thread for that, instead of hijacking this one.
Edwardowen2,
Good luck in finding an enclosure, your father would've been proud of you, I'm sure!
Paul
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