Linkwitz w-frame dipole sub w/15" drivers

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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
 
Me too!

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
 
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
 
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.
 
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.
 
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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.
 
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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.
LINK TO POST 405
 
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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

Thanks, last night I made a big bowl of popcorn, and read the entire "My first Dipole Subwoofer" thread. Towards the end it is explained that one uses the bottom style when stacking multiple Ws.

So I will go with the top diagram.

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

Cheers,

Will definably take you up on that one! Even though I use a laptop in the listening room for real time measurements and adjustments, that will give me a head start.

Dave.
 
An externally hosted image should be here but it was not working when we last tested it.


The speakers I'm using are highly modded Magnepan MMGs, in use but still under construction. Eventually, when everything else is completed, I plan on "socking" them, with MG12 socks.

Planar Speaker Asylum - Deli frame project...in the oven - johnvb - July 12, 2010 at 13:34:24

The Magnepan literature states they go down to 50 hz(+/-3d), although most think that's a bit of wishful thinking:) I'm hoping I can get a good solid 40 to 80 or 100hz from the stereo subs, I actually don't want much output below that.
 
Hi,

the drivers parameters are on first glance well suited for an OB sub, but -and this is a big But- it´s resonance frequency is very low. Typically such drivers can´t be driven hard and loud, because they feature a rather soft supension system. I much more prefer the smaller and optically far more pleasing dipoles after A.Ridtahler. One of the biggest advantages apart from their tiny cabinet size is a considerable reduction of resonance frequency. With 15" and 18" drivers featuring Fs values of up to 35Hz it still allows for Fb values around 20Hz. Qts values between 0.35 and 0.5 work great. Such drivers can be found quite priceworthy in the PA range and behave alot better when driven hard.
Sonically dipole basses are a good match to dipole midhighs, but You should know that they sound all contour and nice kickbass, but not as weighty and without the slam of other subs. Also You need loads of membrane area. A pair of 15" is good for ~30m². Otherwise You would seriously reduce dynamic range, especially if You aim for lowest frequencies, below 30Hz. In larger rooms I would rather opt for a CB-Subwoofer that works below 50Hz and a dipole from 50Hz to the Xover-freq of the Midhigh-transducer.

jauu
Calvin
 
Yes I still plan on using the AE IB15s. Just getting my ducks in a row as far as cutout sizes, VAS, etc. as applied to the original recipe.

The Linkwitz page goes though several types of alternative drivers, with the final one (woofer#3) ultimately also being discontinued. I accidently tripped over the info regarding the "new" recommended driver on the Thor page, assumed it applied to the dipole project also. But that's when I usually get in trouble :)

Anyway, thanks to the info on the Parts Express page, I now have the specs of the original woofer #3, so I'm good.
 
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