New MJK Baffle Article

[Nelson Pass]

he'd suggested any of the PMA series would surpass the DXs on an OB. Have you had this experience?

Finally, I'm open to an active XO. Do you have a sense of when you might release your Active XO DIY plans?

I prefer the Alnicos, but it's been a long time since I've listened to the DX.

The crossover will happen, but it's down the list.

😎

 

[Gyuri]

Hi Papa!
Maybe you would like these speakers.
And what about LA?😎

http://yje88g.bay.livefilestore.com...H7UyzYrOUKpkZj_NH96/DSC_01610001_1.JPG?psid=1

http://yje88g.bay.livefilestore.com..._KBbSQCZXZUu2q8ZZHu/DSC_01620002_1.JPG?psid=1

 

[NYCOne]

I prefer the Alnicos, but it's been a long time since I've listened to the DX.

The crossover will happen, but it's down the list.

😎

Thanks. I am exceedingly curious about your L Cao Alnicos too.

Of course I hope they are the audio unicorn you've mentioned in the past, buying something for $100 that preforms like $1000.

 

[NYCOne]

Here's how I did mine. fe103e over Alpha 15 in H-frame.

How does it sound? I went FF85K over Alpha 15 in an OB without an H frame. I considered the FE103. Some felt it was a bit loud on the highs and would need to be padded, have you found that?

 

[gvimhoof]

Hello NYCOne,

I have been perfectly pleased with these. The Fostex lives up to it's reputation: a bit forward at first, and then it breaks in and gives me a big smile. It's not overpowering the Alpha in the H-frame for me. However, I work in a concert hall, and I listen to mostly concert recordings, and in real life the bass frequencies aren't pumped up the way they are on the radio.

If you like a lot of bass, then I would recommend two Alpha 15 drivers per speaker, but I don't need that. I'm also running these off a little Onkyo TX8222, which only puts out ~40watts per ch. Get's plenty loud enough for me sitting 8ft away from them.

later,
G

 

[Malefoda]

Anyone with the new FF85WK?
http://www.fostexinternational.com/docs/speaker_components/pdf/ffwk.pdf

 

[planet10]

I have 4 on order. According to the last schedule i heard they should arrive in North America mid June.

dave

 

[Malefoda]

Longing for your review, they "look" like between FFxK and F series...

 

[Nelson Pass]

Thanks. I am exceedingly curious about your L Cao Alnicos too.

Of course I hope they are the audio unicorn you've mentioned in the past, buying something for $100 that preforms like $1000.

Don't count on a price in that category. I am informed that almost all the
cost of the SEAS Exotics at $900 or so was due to Alnico. A similar release
with ceramic is slightly over $100.

😎

 

[planet10]

Longing for your review, they "look" like between FFxK and F series...

Yes. FFxx5k cones, FExx7 T/S.

dave

 

[Godzilla]

I've been enjoying the Beta 12lta in a sealed box (plus supertweeter) over Alpha 15 H-frame (powered)... and love it. Will be building open baffle in the coming weeks and compare.

 

[same64]

Hi guys.
Im running 103e at the moment in temporarily baffers but drivers sounds bit edgy .I did some research and it seems some people have used notch filters on the fe103 .Could someone help me with that please?.(have to add that im new to diy speakers)

I was trying to find 85k drivers with no luck..

best regards
Marian

 

[planet10]

I was trying to find 85k drivers with no luck..

Impressions so far are that the FF85wk has the potential to be better than the FF85k

dave

 

[same64]

Hi
Thanks for replay.
85,5 dB its not to low? If its better than 103e for that project i would go for it.
Would i need to change anything in crossover?

best regards

 

[planet10]

I've not had enuff listening to say for sure, but i'd guess yes.

Slightly lower efficiency means that you can get more bass out of the bass driver.

dave

 

[Malefoda]

my take

Hi fellows,

here is my attempt on Martin's smart OB. With a bit of Jim Shearer's style.
30mm oak baffle, they are lovely and heavy but as a friend has done it with my specs... on one baffle drawing, you can see the result. Saldy not both baffles... ='( I'm sad to death...
FF85WK are on their way from USA and I'll use old alnico 15" before I buy modern drivers.

 

[woody]

I am considering biamping. This design calls for a 12db/oct crossover but could
I use 24db/oct on the woffer and 12db/oct on the full range driver or failing that
anyone know how to modify my Behringer cx2310 for 12db/oct slopes and still
use the same xover points?

 

[Jim Shearer]

As one who has built a version of MJK's passive OB: Martin chose the XO points and slopes for a reason, which he detailed in his white paper. I think if you use a 4th order XO on the woofer, you will end up with a dip in the FR response which I would not find acceptable.

Cheers, Jim

 

[woody]

Thanks for the feedback. I looked at the crossover component values and it looks like
this is a bessel crossover. Am I correct or did I miss something?

 

[Malefoda]

No life! Lost to ne next crossroad...

Hi there,

having done the XO, after a while of full range playing, and tunes are on.
I know my amp is not powerfull enough, on paper. Volume is more than needed, but no slam, no life, do power manly do handling more than volume?
I know ringings can happen, speakers, baffle, rooms... I have a bass frequency wich resonate like hell, the same in highs, a peak at something like 2K wich make some pipes notes ears killers.
Beside that great speakers have their fans pointing wich amp best matches that very speakers, but in a thread like this one it's almost the inverse, amps are not much in question, the flaws of the design yes... again, the amp is not to be chosen to match and are these statements done on sepcial "perfect" amps?

And what about room... endless quest 😉