Center channel build with 2226H and D220Ti+PL-000446GP

invalidbuffa

invalidbuffa

Super Member
Hi all,

I'm embarking on a center channel speaker build for my home theater using a JBL 2226H and D220Ti/QSC PL-000446GP waveguide. My objective is to produce a center speaker that will last the rest of my life and would be suitable for installation behind-the-screen in case I have such a setup in the future. For the enclosure, I was thinking of going with something similar in size to a 4Pi (~3 cu ft), but with a 2" slot vent that spans the internal width, for an Fb of about 42 Hz.

I have a couple questions:

Would the 4Pi crossover be suitable with a D220Ti? Is there a different design that might work better (like the econowave XO for >95db woofers)?

How much polyfill stuffing is adequate?

Any thoughts?
 
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If you are thinking "the rest of your life" then just build the 4pi using the B&C DE250 and Wayne's H290C waveguide and be done with it. Fully tested and documented. No second guessing or futzing around.

I've used the the LE14 variant of the ewave XO with the D220Ti on the JBL/Pyle/Dayton waveguide (with JBL 2226H)...not bad at all. Also have used the same crossover (+ zobel?) with the B&C DE250 on the QSC waveguide (with JBL 2226H)....not bad but it resulted in a ~2000Hz crossover point which is less than ideal but sounded fine.

The D220Ti just won't go as low as the DE250 and the QSC waveguide is rather deep which causes phase/time alignment issues ...so I suggest the 4pi solution (even though I could sell you my old ewave crossovers).

Hope that helps. Good luck!
 
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Thanks for your input. I've gone back and looked at the datasheets and now I see the difficulty in crossing the 2226 over with the D220Ti...for some reason I thought the 220 went lower. I'm taking your advice and will get a DE250. Regarding time alignment, I'm probably going to add thickness to the baffle behind the horn so the voicecoils line up.

Any thoughts on the slot vent? There doesn't seem to be a consensus as to the best ratio/size...I've heard that if it's too narrow it will raise the tuning or cause the cabinet to be aeperiodic. I only chose it because the vent would be easy to incorporate into the construction of the box.


Gah I wish I could change the title.
 
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I think I'm going to stick with the QSC. Wayne looked at the measurements on the PL-000446GP and concluded it was very similar acoustically to his H290C. I'm getting ready to order some other parts... Is there a way to calculate how much polyfill I need?
 
FWIW, I can confirm that the QSC and H290C are not drop-in replacements for each other. They have very similar acoustic behavior yes, but there is too much difference in their impedance peaks to get the same xover filter results, and acoustic center offset doesn't match either.

I'm not vouching for this design one way or the other, but here's another complete system that you could maybe get via PM: http://www.diysoundgroup.com/forum/index.php?topic=141.0
 
Thanks for talking some sense into me. The DNA-360 seems more cost effective, given its performance is almost equal to the DE-250. The SEOS 12 waveguide also makes much more sense for nearfield listening as it moves the centers of the drivers closer.
 
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