What OB would you do with four AE IB15's?

I have come into four AE IB15's and would like to incorporate them into an OB build. Woodworking skills are intermediate and free time is scarce. The room they'll play in is 14x20x8, dedicated for listening and acoustically treated. Amplification is big solid state (Threshold, Aragon, Soundcraftsmen) and an ST-70 with a Dared SL2000a tube preamp.

As an owner of Infinity QLS-1's, Acoustat Spectra 22's, and Magnepan MG-III's (I supplement the Stats and Maggies with a pair of 15" Alpha H-frames) I'm accustomed to big scale, big dynamics, three dimensional sound stage, detail and realism. I'm hoping with well selected drivers above the IB15's I can exceed the levels of performance I've experienced from the aforementioned designs.

I've done one DIY build and it was the H-frame Alphas with a 12" Beta (w/phase plug mod) running up to 3.5K where a BG Neo3 took over. This was tri-amped with an Ashley active xover. It was a fun, great sounding build but couldn't rival the big dogs in the collection.

I'm looking for suggestions on basic design, driver configuration, selection, etc.
Front of mind was to run a pair of the IB15's and an Audio Nirvana Super 10, but that's just what my limited exposure to what's available out there led me to first. Hoping you fellas can give me some worthwhile suggestions. Something like the Lotus Grenada (sans the uber expensive drivers) is a direction I'd be interested in. The top side of the NaO Note RSII is appealing as well.

Oh, and I'm a drummer so I need very convincing percussive dynamics and physicality to the presentation....in addition to the usual desirable attributes.

Thanks
Michael
 

dumptruck

Member
2010-05-04 5:02 pm
MN
I think you should use them to install infinite baffle distributed bass in your room instead (should be awesome). The Dipole15 is the one really designed for OB, really good OB dipoles are not easy to design at all, and those are awfully good speakers you've listed to try to exceed with no real experience.
 
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OllBoll

Member
2010-11-22 11:24 pm
I'd say W-frames or ripoles . I since they are AE IB15 you can go low and moving all that air will create lots of vibration so force cancellation would be nice which both of those have. I even better is the W-frames since it also has 2nd harmonic cancellation.

I have 4 AE IB15 I too and I i I'm building W-frames :)
 
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I think you should use them to install infinite baffle distributed bass in your room instead (should be awesome). The Dipole15 is the one really designed for OB, really good OB dipoles are not easy to design at all, and those are awfully good speakers you've listed to try to exceed with no real experience.

Thanks for chiming in, DT. Yes, I've read the Dipole 15's are the best choice for what I'm wanting to do but have also read in several places, including from an AE affiliate, that the IB15's will work in OB just fine (I think he may have stated the downside to using the IB15 compared to the Dipole 15 in OB is limited upward bandwidth extension with the IB). I certainly would have purchased Dipole 15's if I were starting with nothing, but I came into these four unused IB15's for less than the price of one (and wasn't dare going to pass that opportunity up). I was hoping I could configure the IB15's in an H, U orW-frame or an OB with wings because I'm familiar with those designs and know they'll work with the layout of my room. And I'm just looking for a fairly flat response from the 20's to 150 or so (higher would be just fine by me) in the hopes of creating an excellent LF foundation for a host of drivers on the top side. But don't get me wrong... I don't want to try and stick a square peg in a round hole. If I'm sacrificing a butt load of performance and SQ by trying to go OB then I'll certainly entertain what you propose. Can you elaborate some on the specifics of the build (construction, dimensions) and how you might go about executing this wrt room placement, etc.

- Michael
 

dumptruck

Member
2010-05-04 5:02 pm
MN
Yeah, they would probably work just dandy as dipole bass crossed over very low in a 3+way active system (you'd need custom-made active, DSP, or active/passive hybrid, I'd think). That's an expensive speaker and hard to get right without a lot of measurements and experimentation, but hey...

Anyway, as far as IB subs, do you own your living space? Sometimes they are installed in basements(floors), attics(ceilings), sometimes they use the inside of the wall for an enclosure, sometimes they just use massive slim boxes along the walls...
 

OllBoll

Member
2010-11-22 11:24 pm
A thing about the Dipole15 though, I remember Linkwitz testing a Dipole15 and finding that when pushed to xmax there was very much 3rd harmonic distortion. I think John discussed this and he indicated that the normal lambda overhung woofers probably wouldn't have this issue and behave better when pushed to their limits.
 

dumptruck

Member
2010-05-04 5:02 pm
MN
I'm just looking for a fairly flat response from the 20's to
I missed that part before. If you really want the deep stuff, then I'm doubling down on my recommendation for IB or psuedo-IB :D. You'd be able to get below 20Hz at true concert levels. I'd defer to the distributed bass experts for positioning, but you could probably locate two such that they can run a bit higher than subwoofer range as "flanking subs" to support and even out the midbass of any given mains with modest bass response.
 
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4 IB15s

I have the same 4 drivers, and had (have?) the same dilemma.

I settled on a configuration that's basically a U-frame, but incorporates both drivers into a small plenum, a la the brilliant push-pull slot-loaded (PPSL). You can even make the plenum (and slot) narrower (which increases the bandwidth for more flexibility crossing higher) by mounting them push-push. The woofers are such low distortion that it's a completely fine compromise.

I wouldn't worry about losing too much output mounting them as open-baffle - you're talking about two 15" woofers with a linear sweep of about 1.5 liters each. And you have 4.

I haven't yet built the speaker, but I'm very much looking forward to it. People have used much less drivers, on just a wide baffle, and been thrilled with the result. Just my $0.02.

cheers,
-Tal
 
I have four of the IB12s. I currently use them in an H-frame in variation of the Linkwitz Orion.

If I build another speaker, I'm considering a narrow baffle OB using the Nelson pass slot-loaded idea mentioned above. It would look something like this, with the twin IB12s, a Seas W22, BG Neo10 and Neo3.

The choice of drivers is because I have them all on hand.
 

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OllBoll

Member
2010-11-22 11:24 pm
One thing I'm about to try is to use 2x2 IB15 in W-frames and then a single U-framed IB12 in a distributed multisub config and try to hide them away. They are a bit too big to conveniently place under the mains =)

If I remember to I can report back after I've tried it, 2 of the drivers are on order though so is probably a while until I can test it as a full system.
 
I have four of the IB12s. I currently use them in an H-frame in variation of the Linkwitz Orion.

If I build another speaker, I'm considering a narrow baffle OB using the Nelson pass slot-loaded idea mentioned above. It would look something like this, with the twin IB12s, a Seas W22, BG Neo10 and Neo3.

The choice of drivers is because I have them all on hand.

How do you like the four IB12's in the H-frames? What region of bandwidth do you have them operating in?
 
I'm looking for suggestions on basic design, driver configuration, selection, etc.
Front of mind was to run a pair of the IB15's and an Audio Nirvana Super 10, but that's just what my limited exposure to what's available out there led me to first. Hoping you fellas can give me some worthwhile suggestions. Something like the Lotus Grenada (sans the uber expensive drivers) is a direction I'd be interested in. The top side of the NaO Note RSII is appealing as well.

Oh, and I'm a drummer so I need very convincing percussive dynamics and physicality to the presentation....in addition to the usual desirable attributes.

Thanks
Michael

Hi Michael

If you're still considering AN for the top, go for the AN Super 15 (CF, Neo or even Alnico). They will go lower, and give much better dynamics. Personally, I would then add an LCY K100, or much better yet, one of the RAAL tweeters to fill in above 15k. That just the I would do it, but YMMV. :)

Enjoy,
Deon
 
I have four of the IB12s. I currently use them in an H-frame in variation of the Linkwitz Orion.

If I build another speaker, I'm considering a narrow baffle OB using the Nelson pass slot-loaded idea mentioned above. It would look something like this, with the twin IB12s, a Seas W22, BG Neo10 and Neo3.

The choice of drivers is because I have them all on hand.

What would be the xover points between drivers with the design your considering?
 

Jonasz

Member
2003-02-12 9:18 am
Sweden
I would make a couple w-baffles and combine them with the NaO Note RS (or original Note). The sound is awesome! I have an additional quartet of IB15 laying around and maybe that is the next project even though one per side gives enough bass for most situations. :p

One thing though is if you need good percussion you may want more conearea above 100hz and then a w-baffle isn't the best answer bc they need to be crossed at 100hz lower, generally speaking oc.

Note_topbot.jpg
 
I'm digging this old thread of mine back up as I'd like to begin experimenting with my IB15's. Anybody have any new information or suggestions?

Is there software I can use to run simulations so I can see the effects of different baffle widths (and how critical is height)? I'm curious to know what the IB15's would do with a 24" wide baffle and a wing on one side (like the Lotus Grenada).
 

OllBoll

Member
2010-11-22 11:24 pm
The Edge lets you simulate that, if you have a folded baffle then just think of it as a flat one but a bigger one with the same distances. As long as it isn't too big the only difference baffles do is increase efficiency down low the bigger it is, so you can pretty much build almost any kind of baffle without problems.

Dual opposed drivers is always a good idea though, especially in the bass.
 

OllBoll

Member
2010-11-22 11:24 pm
A folded baffle also has resonances so you'll probably have to cross it lower than a flat baffle. If you want to keep a dipole response and mount them in a W-frame you'll probably want to cross them at able 60 - 80 hz. I if you go the flat baffle route you can probably cross about 1.5 octaves higher. This assumes relatively small baffles though, about the size of the LX521 but up sizes from 10" drivers to 15" so about 50% bigger.
 
The Edge lets you simulate that, if you have a folded baffle then just think of it as a flat one but a bigger one with the same distances. As long as it isn't too big the only difference baffles do is increase efficiency down low the bigger it is, so you can pretty much build almost any kind of baffle without problems.

Dual opposed drivers is always a good idea though, especially in the bass.

Thanks for the info. Do you have a link to the Edge software? I searched on google and came up with nothing.