very true! i bought a pair of their p17wj, i thought it could work as a midwoofer but it could not, it sounds decent as a midrange driver but it has no low frequency output at all. strange is also that some of these "vifa classic" does not show up on their website
Yes, i do not remember exactly but both had resonance frequency at 65-70 hz and it never decreased, i believe their data sheet says resonance frequency should be around 37hz
Would anyone know if there are any plans for this TL design. I prefer the slim floorstander look to the IMF style.
For B139?
https://www.t-linespeakers.org/projects/vProjects.html
3 designs across the top. The first 2 could have their cross-section halved for use with 1 B139. These are modern designs, unlike the IMF and many others that are guesses with improvements thru iterative builds (likely the case for the commercial ventures like IMF and TDL).
dave
https://www.t-linespeakers.org/projects/vProjects.html
3 designs across the top. The first 2 could have their cross-section halved for use with 1 B139. These are modern designs, unlike the IMF and many others that are guesses with improvements thru iterative builds (likely the case for the commercial ventures like IMF and TDL).
dave
Could 1 B139 be placed on the narrow side at the same height? For the same look as the Falcon design Or would it need re-designing?
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I dragged out the original drawing, it will not be as simple as that, the driver does not fit if the depth is halved.
Next attempt would be to decrease the width by 2.
dave
Next attempt would be to decrease the width by 2.
dave
Oh wow, thanks Dave. One more question if I may, if I build a small box the same width of this for my b110 and T27’s to sit on top would the distance to b139 be ok or would it cause issues? I plan to swap out either top or bottom, experimenting with different combinations of drivers and crossovers.
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It would be OK, but might be a bit higher than you like for listening purposes. Also creates a significantly large centre-to-centre. A 5” tube out the back (or a heavily tapered midTL [better & take up less line cross-section]) but inside the box just above the woofer.
dave
dave
Ok, I am looking for a modular system for more fun and games lol. If the driver position was lifted could the terminus be then positioned on the front to keep the overall length the same?
Then put a shelf on the sides of the TLs (or stands) to support the sats at the right listening height. On the inside mirror imaged.
If you don’t have the B110 boxes done, this is the design i did for the B110/T27 kits i was selling) and the Fried M sats): http://p10hifi.net/forum/B110-pyramids.pdf
Bud Fried took that and stretched it further, also tilting the baffle backwards — i have the original plans if you want to complicate your carpentry.
dave
If you don’t have the B110 boxes done, this is the design i did for the B110/T27 kits i was selling) and the Fried M sats): http://p10hifi.net/forum/B110-pyramids.pdf
Bud Fried took that and stretched it further, also tilting the baffle backwards — i have the original plans if you want to complicate your carpentry.
dave
Hello All,
I have recently acquired four new drivers, 4 pcs B139 and 4 pcs B110 from Falcon Acoustics, all matched pairs with the idea of building my variation of an Isobaric system. I am a huge fan of old Kef and have been living with it for over 35 years.
I wonder if anybody has experience with the quality of B139 drivers, as the ones I received are, to say the least, terrible. One of the four drivers was rubbing the coil, right out of the box. The remaining three seemed, at first glance, to be all right. To cut a long story short, after a "little" persuasion, Mr. Bloomfed accepted to send me the replacement, a new B139 driver which came with a loose front foil.
After receiving the substitute driver and having a terrible experience with its quality, I took all the drivers to a professional service (NN Acoustics https://www.nnacoustics.com) to check them all thoroughly. The result was that all five B139 drivers were faulty, each with its own flaws. Mainly, the geometry of the coil, loose front foil, and most importantly, the whole membrane structure of each of 5 drivers were dipped from 1 to 2 mm below the resting position. A photo session of the entire situation is coming soon. FYI, B110 drivers were fully ok, no issues at all.
I have recently acquired four new drivers, 4 pcs B139 and 4 pcs B110 from Falcon Acoustics, all matched pairs with the idea of building my variation of an Isobaric system. I am a huge fan of old Kef and have been living with it for over 35 years.
I wonder if anybody has experience with the quality of B139 drivers, as the ones I received are, to say the least, terrible. One of the four drivers was rubbing the coil, right out of the box. The remaining three seemed, at first glance, to be all right. To cut a long story short, after a "little" persuasion, Mr. Bloomfed accepted to send me the replacement, a new B139 driver which came with a loose front foil.
After receiving the substitute driver and having a terrible experience with its quality, I took all the drivers to a professional service (NN Acoustics https://www.nnacoustics.com) to check them all thoroughly. The result was that all five B139 drivers were faulty, each with its own flaws. Mainly, the geometry of the coil, loose front foil, and most importantly, the whole membrane structure of each of 5 drivers were dipped from 1 to 2 mm below the resting position. A photo session of the entire situation is coming soon. FYI, B110 drivers were fully ok, no issues at all.
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These are the promised photos taken by the service person. In my humble opinion, they bear little resemblance to KEF products and, more importantly, fail to meet KEF's quality standards. There's no way to consider these as drop-in replacements. I want to emphasize that these drivers are new and unused. Could anyone please advise on how to proceed with this matter? Has anyone else experienced something similar? Falcon Acoustics has let us down.
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Gile. I hope you don't me saying, but maybe it's a shame that you did not buy original B139 drivers as there seem a few for sale on EBay and at quite reasonable prices it seems. I wonder if it's worth buying a pair to trial as a backup?
Best wishes for your project.
PS. I may have a pair of B110 (SP1057 type 8 ohm) If you need them, just PM me..
Best wishes for your project.
PS. I may have a pair of B110 (SP1057 type 8 ohm) If you need them, just PM me..
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If they are out of spec the usual thing to do is return them for ones that are in spec or for a refund.
In Hobby Hifi magazine Oct/Nov 2020 there is a long article with lots of measurements of BBC original drivers and Replica.
In germany Hifi sound is selling them
https://www.hifisound.de/de/Hifi-Ko...-Furnier.html?listtype=search&searchparam=Bbc
In germany Hifi sound is selling them
https://www.hifisound.de/de/Hifi-Ko...-Furnier.html?listtype=search&searchparam=Bbc
The idea was to acquire new drivers, but certainly not replicas. They have been advertised as drop-in replacements, even upgraded. Allegedly, Mr. Malcolm Jones brought with him the license to Falcon Acoustics. Sadly, I was naive to believe that Falcon could match KEF's quality. As for the potential return of these, Mr. Bloomfeld presented himself as a hard negotiator, unwilling to accept that these came faulty. Please check my initial post for details.
I will attempt to contact Mr. Bloomfeld once again, albeit with reservations about the likelihood of success. The aim is to gather feedback if anyone has had a similar experience with Falcon B139 drivers and to caution fellow DIYers.
I will attempt to contact Mr. Bloomfeld once again, albeit with reservations about the likelihood of success. The aim is to gather feedback if anyone has had a similar experience with Falcon B139 drivers and to caution fellow DIYers.