[kyrill]

this is a very good looking design

for the 2 bass speakers i will try out GR-research servo woofers who can accommodate to 200 hz.
I like though, the midrage to take over at between 100-150hz

See how far i can come

I also I am a believer in  a modest U frame ( modest to avoid resonance under 200hz) behind the main baffle

[JPotgieter]

Impressive woofers! Here's a link http://www.gr-research.com/index.asp?PageAction=VIEWPROD&ProdID=139

Are you allowed to upgrade speaker before you've finished them?

The Jamo crossover design is very forgiving - by changing the large series inductor to get a smooth transition to mid-range it is possible to make any 15" woofer work. These will certainly out play the alpha's.

Don't know about crossing over to mid below 200, excursion was a problem for me going anything lower than the current 210. It did sound much better letting the mid play down to 100.

[kyrill]

yes , lower than 200hz may get excursion problems

That is why i want a baffle that start to roll of  below 100hz if that is possible
so the mid does not to be equalized for the baffle loss

[JPotgieter]

Here's parts list from Madisound. Still contemplating replacing C3 with a Mundorf Supreme cap!

Low         

C1   300 uF       Bennic 280 mfd Electrolytic 
L1   20 mH      Sledgehammer 20.0mH 15AWG Steel Laminate 

Mid         
L2   0.7 mH       Sidewinder 0.7mH 16AWG 
C2   100 uF       100 mfd Solen Fast Cap 400V 
C4   10 uF       10μF PX Range Polypropylene Capacitors 
L4   3.5 mH       Sidewinder 3.5mH 16AWG 

High         
C3   5 uF       4.7μF SA Range Polypropylene Capacitors 
L3   0.55 mH       Sidewinder 0.5mH 16AWG 

[JPotgieter]

Before ordering just one more listening test. If L4 is changed to a 2 mH inductor it changes the crossover to 1'st order, the mid and tweeter phase should then be reversed. Summed model output is similar after tweak.

[derik736]

Hi guys,
since about 3 years, i listen ONLY open baffles. Lot of drivers, lot of baffles and lot of mistakes i left behind me (ex. Goodmans Axiom 201, 301, University, Altec, Saba, other german, all vintage drivers..). When i first time saw Jamos, i just had to hear them. Not long ago i found one pair by a local HIFi dealer, connected to a pre-power combo from AARON and some tubed cd-player which looked like shanling but firmed as something else. Well.....in my ears it was a nightmare. Kind of sound which i hate, no life at all, absolutely flat, no bass, very bas middle range. The worst system i´ve ever heard in range of 20k euro. Next day i took a good friend of mine to verify my own feelings about them. Same story. We took  Mike Oldfields "Tabular Bells" which we know very good, there was some very good known sounds which you couldn´t hear at all. We even checked all cables, just to be sure if everything is connected well. It was disaster. I do not see any reason to clone them except of the visual aspect. My personal opinion.

As for me, i´m very happy with my OB. Altec Biflex 420 as woofer, saba greencone makes the rest. Very simple XO, 1st and 2nd order, works fine for me. I will probably cut biflex a lttle bit deeper, now it plays up to 2500hz, than saba takes over. Just need proper looking baffles, and my very own audio nirvana, after years of looking, is very very close. Bass response is extended due to fact of using loudness function, somehow it works better than i thought, bass is very fast and precise.
Will post some pictures very soon.
Greetings

[opnly bafld]

Hello Derik,

Thanks for posting your experiences. 

Lin

[dmiller]

Questions on cutting the speaker holes on a warped baffle.  What's the easiest way to do it? If cut before warping, the holes become distorted. My jig will not work on a curved surface.

I believe the Jamo baffles were made by gluing up thinner sheet of MDF that rested on a curved frame. I like this way of constructing heavy, curved baffles. It aesthetically pleasing and should reduce the >2x problem with smaller drivers.
Thanks.

[ttan98]

Apparently there is a new Jamo OB, called R907, go to this site for a detailed review:

http://stereophile.com/floorloudspeakers/jamo_reference_r_907_loudspeaker/

My believe here are many DIY OB speakers out there that sound better than the Jamo, at a fraction of the price Jamo is asking for this model, retail price, US$10,000. I think one can build a pair of very good sounding speakers for less than US$2,000 using  high quality drivers and passive components and throw a carpenter making the baffle.

cheers.

[AK]

I doubt that a carpenter can make baffle like one in Jamo.
looks like it's made with some kind of gigantic steam press
besides Jamos' baffle design is very aestetic.
I've never seen good looking diy OB's. the best we can do is to use straight baffles and hide them behind curtains
If I had 10k to spend, I would get Jamos without hesitation.

[Telstar]

for the 2 bass speakers i will try out GR-research servo woofers who can accommodate to 200 hz.
I like though, the midrage to take over at between 100-150hz

See how far i can come

I also I am a believer in  a modest U frame ( modest to avoid resonance under 200hz) behind the main baffle

I think we are on the same wavelenght
Did you find out more about U frame designs?

yes , lower than 200hz may get excursion problems

That is why i want a baffle that start to roll of  below 100hz if that is possible
so the mid does not to be equalized for the baffle loss

Any progress on this (whether or not its a jamo clone i dont care)?

[dmiller]

I doubt that a carpenter can make baffle like one in Jamo.
looks like it's made with some kind of gigantic steam press
besides Jamos' baffle design is very aestetic.
I've never seen good looking diy OB's. the best we can do is to use straight baffles and hide them behind curtains
If I had 10k to spend, I would get Jamos without hesitation.

I'm not so much trying to make Jamos as thinking about shaping MDF. Some of the best cabinet makers in the world do it as a hobby out of their garage. For these guys making the Jamo baffle would be trivial. I. am not, however, one of those guys.

I agree that most OB designs are scary ugly. But I like Ed's:
http://www.audiocircle.com/image.php?id=12941

[Rudolf]

I agree that most OB designs are scary ugly. But I like Ed's:

If you like it a bit extroverted, even sexy - how about this one:



It is a new dipole design by the German magazine Hobby-Hifi http://www.hobbyhifi.de/Aktuell/Aktuelle_Ausgabe/aktuelle_ausgabe.html
featuring a 12" woofer, 5" mid and a pair of magnetostatic foil tweeters. If somebody is fond of real wood applications in his car - that´s for him.

[Bob in St. Louis]

The image doesn't work, but if it's the same as the photo in the link it reminds me of a Salk speaker. Very cool.

Bob

EDIT: NOW the image is working. 

[AK]

well it's a matter of personal taste. there are few diy designs that stand out, but I still wouldn't put them in main living room. I need to do some research, maybe I underestimate carpenters abilities. IMO that's the cool baffle that sells Jamo speaker. Even reviewer wrote "It made no sound, but it was beautiful, and I wanted it." I have exatly same impression
don't really care how they sound, just want to have them

[dmiller]

I agree that most OB designs are scary ugly. But I like Ed's:

If you like it a bit extroverted, even sexy - how about this one:

[/quote]

Now that's an easy build. I'm not sure I understand what the clear plastic look is about. The back of one woofer looks enclosed in plastic.

[Rudolf]

I'm not sure I understand what the clear plastic look is about. The back of one woofer looks enclosed in plastic.

Sorry, it´s the silver cables from the tweeter and midrange driver led in a loop around the woofer magnet. Now that you called it clear plastic, it really looks like that on the photo.

Rudolf

[Angaria]

what were the qts and xmax on the bass woofer pictured?

I agree that most OB designs are scary ugly. But I like Ed's:

If you like it a bit extroverted, even sexy - how about this one:



It is a new dipole design by the German magazine Hobby-Hifi http://www.hobbyhifi.de/Aktuell/Aktuelle_Ausgabe/aktuelle_ausgabe.html
featuring a 12" woofer, 5" mid and a pair of magnetostatic foil tweeters. If somebody is fond of real wood applications in his car - that´s for him.

[jeenie67]

Hi, check out my post   Dipole....

[THWO]

Hi all,
the question came up how to create a smooth curved baffle. I did not yet try it myself, but may be it could work as follows: First layer is a flat board, as usual, followed by curved horizontal profiles on top (being wide enough in vertical direction around the woofer cutouts to still offer enough support and enseeling after the cutouts are made) and on top thin sheet(s) being bent around / glued onto these curved profiles. Space inbetween filled with sand or plastic foam. Well that´s no new idea so far, the problem seems how to get nice round holes for the speakers. Now: How about placing another flat board on top, being stabilized and "balanced" by sufficient vertical wood stripes underneeth and firmly fixed on the outsides of the curved board so that it cannot move against the baffle? Then we would have the flat support for a router to start diggin´. A problem may occur the more curved a surface´s shape will be causing a major distance between the top support board and the  curved board as it may become to big for the maximum length of a router. Should be included in the design considerations. But if that all suits, the router could be in a position to create nice round circles for the outer diameter of the speakers although the final baffle will have a curved shape. The inner diameters may be done by jigsaw from the back side.

May be I explain a bit complicated, please excuse my english.

I like the Jamo´s optical design as well. Might be worth to give it a try with other technical setup.

Till