Linkwitz w-frame dipole sub w/15" drivers

[johnvb]

Has anyone here built the w-frame dipole subwoofer using 15" drivers? Can the standard plans be modified for the larger drivers?

I have four AE IB15-8 ohm drivers that I would like to use to complement a pair of small Magnepans. I also have a Behringer DCX2496 to be used as EQ and crossover.

AE Speakers --- Superb Quality, Unforgettable Performance, Definitely.

This is a music only system, played at low to moderate levels, in a 11/6 x 15 dedicated room. Would like to keep the floor vibrations down, thus wanting the W frame design.

Thanks
John

[taloyd]

Josh,

Have the EXACT same plans (compact W-frame, using a pair of AE IB15-8 drivers)... not yet at the construction phase, but am definitely following this thread, and will chime in with updates.

I see no reason why the plan can't be modified for larger drivers... especially if you're low-passing the W-frames at a lowish frequency (60 - 100) with the Magnepans...



cheers,
-Tal

[johnvb]

Hey Tal. Looking at the plans on the Linkwitz site, seems like everything is sized for minimun clearences around the drivers, although I don't know how the one driverless slot is sized.

Maybe just take the percentage of the increased size of the AE driver vs the 12" one recommended by Linkwitz, and apply that to all the measurements? I know, sounds too easy.

Dipole Woofer

[Davey]

John,

You'll need to scale the frames upward in size to accommodate your drivers. Take a lot of measurements and think about how you'll assemble the frame, install the drivers, which panels to leave removable, etc, etc.

You'll have to take some measurements post-build to identify the cavity resonances and any other items that might need attention when you EQ.

Cheers,

Dave.

[johnvb]

Thanks Dave. On the MUG I should of stated I already had the 15"ers. In my room with the MMGs I probably could get by with just slapping them on an open baffle. Might still try that first, with some spare plywood.

But the bedroom is directly under this room, thus want to keep down the vibration.

Figured I would install the top and bottom panels with machine screws and brass inserts (and some of that blue Loctite stuff too), to access the drivers.

[johnvb]

So there are two configurations of the dipole sub cabinet on the Linkwitz site.

This one:

http://www.linkwitzlab.com/images/graphics/d_woof6.gif

And this one:

http://www.linkwitzlab.com/images/graphics/stk-woof.gif

Can either be used to get the same results, or is the lower diagram only to be used when stacking cabinets?

[taloyd]

The first picture (d_woof6.gif) has one of the drivers reversed for even-order distortion cancellation... it'd be preferred for a single cabinet.

-Tal

[Davey]

Sounds like a fun project. Give me a holler when ready and I can fix you up with a preliminary DCX2496 setup file.

Cheers,

Dave.

[Gary P]

They will work great for your application. As mentioned earlier take your time and do lots of measuring to make sure all will fit.

I have been listening to and tweaking semi cardioid subs build with the Dayton IB385 15" open baffle drivers for several years now. Plenty of output for music and movies and very clean. The AE speakers will be better than the Dayton's I used.

The original version EQ was provided by a Behringer 24/96 ultradrive pro. Current version has crossover and EQ duties handled by Frequency Allocator running on my media computer using a modified Layla 24/96 for output.

The current version is EQed for -3dB at 20Hz. Earlier versions were -3dB as low as 14Hz.

[bentoronto]

Speaking as an ESL person, we've always had to deal with subs that just can't be ESL. I'd say the same thing about OB - no sanitary way to make bass satisfactorily even though OBs are quite nice otherwise.

Get your OBs to work down to 120 and do the sub some other way. It can be a mixed bass at any frequency below 140 Hz and located anywhere in your music room*. I doubt there are any real advantages to "OB sound" at low frequency, so why try to make bass that way?

Having said that, you can make a giant OB like I did. But it makes no sense and has no benefits to try to squeeze it into the front pair instead of a properly located room location.

*Some people say 80 Hz is as high as you can go. But I say 43 years experience with mixed bass tells me 140 is OK.
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