Help needed with original Focal Xover

[seebert]

Hello to all. I'm new to the forum although I've been a "lurker" for a long time and have learned a lot (and enjoyed the process) about DIY audio. My problem / question is this: I got hold of a set of Focal drivers from a pair of old/damaged cabinets but the crossovers were pretty broken up (no- not by me) on removal - they were glued in as components and not on a board and regrettably they weren't removed with a lot of care 🙁 The drivers are Focal 8K415S woofers (X4) Focal T120Ti02 tweeters (2) in what apparently was an MTM configuration. I've uploaded pics of the Xovers together with my feeble attempt at a sketch: can anyone please help me "complete" the dots and show what the finished Xover should be like. I'm a total newcomer to Xover design (even after reading a lot) and really cannot quite figure out where the XO connects to the drive units, and where that 10W 6.8 ohm resistor should go - it was broken off in both XO's. All R's are 10W ceramic and all the parts look to be of high quality - well, of substantial build if that's any indication of quality. BTW I'm an oldie being 69 years old but I still hear well enough to still enjoy good audio sound having started in the 50's with (what was then inexpensive) Quad II's and Quad ESL's. Any help will be most gratefully received.

 

[jerome69]

These are good drivers.
The datasheet :
http://lephenixnoir.net/images/pdfs/8k415s.pdf
http://lephenixnoir.net/images/pdfs/t120ti02.pdf
You can use Focal's recommendation to make the box e.g. 90L@33Hz
I am taking a look on the crossover and come back later 😉

 

[jerome69]

I try to redo the crossover... Very strange crossover. I have already seen a bizarre crossover on a Focal/JMlab Speaker profil 7, i redid it too.
You have a big bass bump +8dB in the low end. I suppose the original crossover depends on the original box.

I suggest a second crossover, if you are not satisfied by the first crossover. This crossover is more simple with better sensitivity but to cope with the 90dB of the tweeter, it's better to use the woofer in series.

You should flush mounted the tweeter to have a smooth response.

I know very well the 6K version, it is a true high end driver 😉


Have Fun.

 

[seebert]

Thank you very much for the input and information jerome69: I really appreciate your time and effort to help me. The original boxes were broken up before I had a chance to get some measurements and pics. (sad!!) I am not new to audio but have never even attempted to design a XO so your comments and help are terrific. I was even thinking of "sinking" the tweeter about 1/2" into the baffle and routing in a dispersion curve as my listening room is far from perfect and can't be changed unfortunately. I will do as you suggest, and again, my thanks for your help.

 

[seebert]

jerome69: I just tried the links and get this :
Pas d'autorisation d'accès direct aux documents ! Connectez-vous au site pour récupérer le document souhaité.

Any ideas please?

 

[jerome69]

Select or click on the url and press enter, the file will appear 😉

 

[AllenB]

I hope this helps.

I am guessing the 6.8 ohm resistor might fit into the tweeter level somehow.

 

[seebert]

jerome69: Select or click on the url and press enter, the file will appear ...

And you are SO right ... it did. I didn't think of clicking on the URL ... maybe I'm way overdue for my annual CATscan 🙂 Again, many many thanks.

 

[seebert]

AllenB: what can I say except a huge thank you for your taking the time to help me on this and marking my drawing as you have. I had zero idea of where to even start. I had been told that the members of DIY Audio are a helpful bunch of like-minded audio enthusiasts but I never expected to get the fantastic help that I've received. Thank you all.