KEF BD139 passive radiator specs?

[Joschl]

Hello folks,

I would like to use a pair of KEF BD139 (SP 1332 from 1993) passive radiators but I can not find the specs anywhere.
I just know that Sd = 349cm^2
But it would be nice to know Vas, Fs and Qms.
Anybody out there who has this information?

Kind regards and all the best for 2009.

Josch

 

[Jonathan Bright]

hi Josch. Probably your best hope is a Kef site in the UK. Just type in "hifiloudspeakers" into your search engine and the first site will probably be it. They only deal with KEF speakers and drive units. They should be able to help. <Merry Xmas. Jonathan

 

[AndrewT]

the datasheets are on KEF's website, as are all their DIY driver product range.

 

[Joschl]

Thank you for the information. When I tried to enter the site before it seemed to be a dead link but now it works.

How about measurement on passive radiator units?

Br
Josch

 

[speakerdoctor]

Checked the KEF site and couldn't find detail specs on their drivers.

I do know Seas publishes specs on their passive radiators. The specs include an invaluable chart showing helmoltz resonator freq. vs cabinet volume for various added weights. Something that comes in very handy for tuning your radiator.

 

[Joschl]

That is a good hint. Thank you. I think I will take the H9946 SP26R datasheet (same Sd), play a little bit with WinISD and the rest is trial and error
Br
Josch

 

[Jonathan Bright]

Sorry Josch my earlier post was confusing. "hifiloudspeakers" is a site devoted to KEF units but not an official Kef website. Have you tried it? There are contributions there on the passive radiator but not necessarily exactly what you want. Some guys from Germany have sent in material. They may be helpful to follow up. Good luck.

 

[a.wayne]

Are B139's still in production ?

 

[Joschl]

No prob. I recognized that before. Unfortunately the forum there seems to be some kind of dead and the search gave no results for "SP1332".
I will gather some material about designing loudspeakers with passive radiators and start with test box next year. Playing around with WinISD gave me an impression how the parameters of the BD139 will influence the frequency response.
Br
Josch

 

[Joschl]

As far as I know the B139 and any other diy product from KEF is no longer produced. My units are from 1993.
Br
Josch

 

[DAMIC]

http://www.hifiloudspeakers.info/Anatomy/KEFDocuments/KEFGermanGallery/pages/p41.htm

Here are some info about BD139 SP1037 and SP1082. Hope that
SP 1332 could have similar parameters.

 

[tiefbassuebertr]

Hello folks,

I would like to use a pair of KEF BD139 (SP 1332 from 1993) passive radiators but I can not find the specs anywhere.
I just know that Sd = 349cm^2
But it would be nice to know Vas, Fs and Qms.
Anybody out there who has this information?

Kind regards and all the best for 2009.

Josch

As I know the BD139 was identical with the B139. The only difference was the not mounted magnet system. Thus the parameter for Cms, Mms, Fres and VAS are identical.
Here some URLs:
http://www.zz-netz.de/elektronik/plaene/kef-b139-spezifikation.gif
http://www.zz-netz.de/elektronik/plaene/KEF-B139SP1044.jpg
TL Links
Article | KEF Reference Series Model 104 loudspeaker | Page126 - February1974 - Gramophone Archive
http://www.kef.com/uploads/files/en/kef_units/A History of Kef Drive Units issue 3.pdf

OTOH - this passive radiators was not intended for commonly applications, but only for the recommended setups from KEF.