My open baffle dipole with Beyma TPL-150 - Page 9

StigErik · 27th April 2009, 08:08 AM

Quote:

Originally posted by mige0

four 18" !

Yes - within its limitations - the bass quality of OB is second to nothing IMO

Michael

I've listened to my OB prototype for a while now, so it was time to turn back to my reference - the big Gjallarhorn 418 towers with its four 18" in sealed boxes. Its was quite interesting.... and disappoiting! Especially the bass is nothing like the OB speaker at all. Yes, there is more LF extension, but the bass quality is far from what I achieved with the OB experiment. The OB also presented a larger stereo image with more depth.

I guess the next project will be to redesign my 4-way towers to become OB speakers. Maybe four 21" per side will do?

mige0 · 27th April 2009, 03:03 PM

Quote:

Originally posted by StigErik

I guess the next project will be to redesign my 4-way towers to become OB speakers. Maybe four 21" per side will do?

There was a guy who did *a lot* of 15" in OB - basically from side wall to side wall and to maximise count he did fold 'em slightly.
I was searching for his page but couldn't find any more.

I guess he found what he was looking for in bass...

I's been Beymas as well IIRC !

Michael

meister_gue · 27th April 2009, 03:32 PM

4*21" on each side will probably fill half of the listeningroom, but I really like the idea. This must be a really impressive system to sit in front of...

Rudolf · 27th April 2009, 03:59 PM

Quote:

Originally posted by mige0

There was a guy who did *a lot* of 15" in OB - basically from side wall to side wall and to maximise count he did fold 'em slightly.
I was searching for his page but couldn't find any more.

Bert Doppenbergs system at BD Design, but not OB:
Total 12" woofers used - 32 x Beyma 12BR70 (16 per channel)

mige0 · 27th April 2009, 04:11 PM

Quote:

Originally posted by Rudolf

Bert Doppenbergs system at BD Design, but not OB:
Total 12" woofers used - 32 x Beyma 12BR70 (16 per channel)

Yes thats the one - sadly its *not* OB...

Thanks Rudolf !

tinitus · 27th April 2009, 04:51 PM

I may be wrong, but as I remember it, it is originally a very big basshorn thats been rebuild and "reversed", with multiple subdrivers mounted in the horn mouth, using the horn as closed "box"
I believe its a BD customer, or member of his forum or something

Rudolf · 27th April 2009, 05:07 PM

Complete information and history here.

tinitus · 27th April 2009, 11:44 PM

Well, it does sound like its Doppenbergs own last big basshorn, converted into this multi woofer arrangement

But though its not OB as mentioned, it very well could be

When I first saw it some time ago I actually thought of doing a similar multi woofer setup, but in a dipole design with AEs cheap IB15

But I dont have the space fore it yet, but I may have in a few years
But I reckon I will consider it a bit too crazy

I dont know, but with better woofers, less than half the woofers might do just the same, if spread out a bit more

mige0 · 11th May 2009, 07:33 PM

Stig - you not have given up - no?

Michael

StigErik · 12th May 2009, 08:12 AM

Time is the main problem now... and the 21" Beyma woofers have not yet arrived. I've redesigned it a little bit to avoid too many weird angles, making it easier to assemble. The MDF boards are sitting in my garage right now!! Hopefully my and my buddy Lars will have time to work in the project again next week.

Below is the latest design, I call it Prototype MKII.

We will make the cutouts behind the mid and tweeter a bit wider than shown here to avoid cavity resonances.

27th April 2009, 05:07 PM	#87
Rudolf diyAudio Member Join Date: Mar 2003 Location: Germany	Complete information and history here. __________________ www.dipolplus.de

11th May 2009, 07:33 PM	#89
mige0 diyAudio Member Join Date: Jan 2005 Location: Austria, at a beautiful place right in the heart of the Alps.	Stig - you not have given up - no? Michael __________________ Audio and Loudspeaker Design Guidelines

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27th April 2009, 03:32 PM	#83
meister_gue diyAudio Member Join Date: Feb 2008	4*21" on each side will probably fill half of the listeningroom, but I really like the idea. This must be a really impressive system to sit in front of...

27th April 2009, 04:51 PM	#86
tinitus diyAudio Moderator Join Date: Nov 2005	I may be wrong, but as I remember it, it is originally a very big basshorn thats been rebuild and "reversed", with multiple subdrivers mounted in the horn mouth, using the horn as closed "box" I believe its a BD customer, or member of his forum or something

27th April 2009, 11:44 PM	#88
tinitus diyAudio Moderator Join Date: Nov 2005	Well, it does sound like its Doppenbergs own last big basshorn, converted into this multi woofer arrangement But though its not OB as mentioned, it very well could be When I first saw it some time ago I actually thought of doing a similar multi woofer setup, but in a dipole design with AEs cheap IB15 But I dont have the space fore it yet, but I may have in a few years But I reckon I will consider it a bit too crazy I dont know, but with better woofers, less than half the woofers might do just the same, if spread out a bit more

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