Passive sub for Magnepan 3.6r?

thanks for the feedback. i auditioned the maggies in optimal conditions--acoustically treated room, speakers seemingly well placed at least five feet from the wall, driven by a big old boulder amp (certainly more than 500w + @4ohms)-- so i don't think the set up or associated gear was the issue. we also crossed over the REL at 40 (consistent with what macdadtexas does), but all of us still heard the disconnect. i'm sure audiokinesis's analysis of the room interaction is correct--he seems very knowledgeable--but i still wonder whether using one amp (rather than an amp to drive the maggies and the sub's amp)might be a more cost-effective solution; hence my initial question about using a passive sub.

To integrate a sub you have to play around with location a bit. I heard a pair
of JL 212s with a pair of Maggie 20.1s and the integration was seamless. it
was put together by Seattle's best high end shop, who definitely knows what
they're doing.

I would think that a really good sub candidate for Maggie would be the
Martin-Logan powered subs. Since they're made to integrate with
electrostatics, they are very fast and light, and fill that 40-100 Hz area very
well. One of the ways subs have trouble supplementing panel speakers is that
many of them are relatively slow. The JL and Martin-Logan are lightning-fast,
however.

Also, Maggie makes a separate woofer. Not quite a sub, but it supplements
the bottom end and makes sure it's flat to 40 Hz. They are passive, made to
blend with decor, and are reportedly fairly inexpensive. They are easier to
blend because, being panels, they're as fast as panels, and they have a
frequency response up to 7KHz.

The Magnepan passive woofers are made of a smaller version of the bass
panel of a 20.1.

good thoughts, johnnyb--i've generally assumed that subs aren't so placement critical nad didn't really think of the spped of the panels relative to the sub (esp. since everyone claims how musical the REL is). i'll hunt around to see how users like the maggie/ml sub combo or passive woofer.
again, many thanks.

Right now Audio Advisor has a sale on ML subs. They're certainly some of the most nimble and musical I've personally heard.

Hi Martykl,

Thanks for your comments.

A dipole can be modelled as two monopoles separated by a path length (the wrap-around distance) with the polarity reversed on one of them. In fact, that's what a dipole is! Take a Maggie and build it into a wall, and on either side of that wall you'll have a monopole source.

It's true that a dipole does not have the same in-room behavior as two asymmetrically-placed monopoles, but both of them more closely approach the same desirable end result: Greater in-room bass smoothness. This is backed up by several AES papers, and I can dig up citations if you really want but frankly would rather not go to the trouble. My point is, their effect is similar enough to make them easily compatible in the crossover region.

Regarding equalization, if it's addressing a global problem then it will be an improvement throughout the room. If it's addressing a local problem, then it will improve the response in one location but may well make it worse in another. How big that "location" is depends on the specifics, but I agree it's not a head-in-a-vice thing.

Suppose in one location you have a +3 dB peak at 50 Hz, and elsewhere you have a -6 dB dip at the same frequency (this is not at all far-fetched with a single-sub system). That's a 9 dB difference. Equalization cannot fix the 50 Hz region at both locations simulaneously; it can fix one, but at the expense of making the other even worse.

Note that one worthwhile advantage of a distrubuted multisub system is that the variation in bass response from one location to another throughout the room is greatly reduced. So any remaining significant problems are more likely to be global, and therefore EQing them is more likely to be beneficial throughout the room.

What I've been talking about in my posts here is only one aspect of getting good in-room bass from a subwoofer system, but it's the one most relevant to integrating well with dipole main speakers.

Duke