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Two way build with Definimax 4012HO and DE250 [message #77220]

Sat, 20 July 2013 07:52

reynold7806
Messages: 7
Registered: July 2013

Esquire

Hi Wayne,

I'm planning to a two way box with a 12inch woofer and a CD with a horn. But which 12 in woofer should I use is a big question, which puzzled me for a long time. After I researched a lot in the internet, I found the 3pi, which is highly regarded, so I decided use definimax 4012ho and DE250.

I have a question. I know from this forum that the 3pi is a little biger than 4pi, that means the internal volume of 3pi is about 90-100l. But I simulate 4012ho in WinISD, the recommended alignment is QB3, and the volume is 37L. If i choose SBB4 alignment, the volume is about 33L. I found when i use 40L and fb=40, the FR looks good and similar to the FR of 2226H in SBB4. So, why do you use so big a box?

Another question, can you please send me the crossover circuit schematic when using definimax 4012HO with De250. The horn will be H290S.

Thank you.

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Re: Two way build with Definimax 4012HO and DE250 [message #77223 is a reply to message #77220]

Sat, 20 July 2013 10:01

Wayne Parham
Messages: 18785
Registered: January 2001

Illuminati (33rd Degree)

The Definimax woofer provides a nice upgrade path for the three π speaker, with its shorting ring and damped cone construction giving really smooth midrange. The bass alignment is EBS, which gives smooth rolloff and additional extension to blend with flanking subs.

I've sent plans to your address, which includes the crossover schematic. It is optimized for the H290C, which is a waveguide/horn with an oblate spheroidal flare profile. If you intend to use the older Eminence radial horn, you will want to delete the resistor in position Rs and add a 0.47uF capacitor in position C1. But the DE250 driver uses a bolt-on mount and the H290S is a radial horn with a screw-on mount, so they aren't compatible without an adapter. I think you would be better off using the H290C waveguide/horn, and the freight forwarding service available in the shopping cart makes international shipments inexpensive. So check that out.

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Re: Two way build with Definimax 4012HO and DE250 [message #77228 is a reply to message #77223]

Sat, 20 July 2013 22:04

reynold7806
Messages: 7
Registered: July 2013

Esquire

I have received the plan. Thank you.

I can get the adaptor from Eminence for H290S. But after I read your post about H290C just now, I know it is not easy to find a substitute. So, I decide to purchase H290C directly from you.

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