$1500 to power Magnepan MMG + MMGC

I would say the XPA-3 would meet your needs nicely. Maggie's are low impedance and my L/R's are too and never audibly clip. Emotiva amps also seem to be well liked by many Magnepan users (or at least I've seen this online). I have an Onkyo 5508 pre-pro and like it a great deal and I think other Onkyo products might meet your needs although there are Onkyo haters out there.

I'm using three Emotiva amps, a UPA-5, a UPA-2, and an XPA-3. I use a Behringer EP4000 for my subs. I need a lot of amp channels as I use active crossovers. I don't have any Maggies but have liked them for decades, if only I had the space.

It really depends on how loudly you listen. If the MMG's behave like the 1.6s I used to have, they don't have impedance dips - - they sit right at 4 ohms (except in the crossover on the 1.6s, which exceeds 4 ohms).

I powered my 1.6s successfully with a Bryston LP2B and also with a Denon AVR 2809 ( I think). But I very seldom reach even -15 dB from reference on movies, and do not typically play music very loudly either.

If you are going to push them hard you should either find a receiver that is both specified and third party tested to be strong into 4 ohm loads or get outboard amplification, to avoid overheating a receiver that's not built to handle the load the Maggies present.

I'd be very tempted to pick up a Denon 4311 (should run under $1500 based on recent threads) and forego the amp initially. It will probably drive the MMG series fine and offers much more advanced room correction, a useful feature.

What are the surround and rear speakers?

How large is your room (dimensions)?

The Denon 4311 is also capable of adding an amp in the future if needed. The better version of Audyssey may well be worth the price difference. I would go for the 4311 for now as it should power those speakers. IMO, it's one of the very best future proof AVR's out there, if there is such a thing. It certainly leaves plenty of room to upgrade with additional amps as needed.

+1. I powered my old MG-IIIa's with a 75-W tube amp in a slightly smaller room for years. (What matters is the distance from them, less so than the room size.) Dipoles have more issues with room interaction by nature. Another thought is to get the less expensive receiver, skip the amp, and pick up some room treatment.

Is the $600-$700 really worth the upgrade of the Audyssey feature? Anything else the 4311 has over the 809 that would justify that price jump?

XT32 IMO would/could be worth the difference. If you look at what Audyssey pro cost and compare what it does to XT32 it doesn't appear to me to that much different. I've used XT but not XT32. XT is not all that and a bag of chips to me. I haven't been following the 09 series Onkyo's as close as I used to as I'm not in the market for an AVR at this time and hopefully for a long time. The 4311 does have 9 amps, don't know about the 809. It also has a host of other features that you would have to jump to a higher model model to get. The cost of the 4311 at this time makes it a bargain IMO. The 09 series Onkyo's do appear to be better than their few years back previous models as far as trouble goes. That 4311 is just steady and ready to go. Take into consideration also that Denon's replacement for the 4311 is going to be much higher in price. Grab a 4311 while you can if possible and you should be good to go for years to come.

+1 to the 4311... Or an sc57 or sc55 which will give you slightly more headroom, but doesn't allow for subwoofer EQ adjustments. MCACC is still behind in that.

Youll get a nicer pre amp section too in the 4000 series!

The 4311 is a good suggestion.

I never understood where the idea tha maggies require a lot of power came from. Is it because they're rated at 4 ohms?

I've owned many 4 ohm speakers and have never noticed any difference between driving them and 8 ohm speakers.

My maggies have no trouble being driven by run of the mill AVRs.

I'd imagine you must have great amps powering your speakers? And what do you consider run of the mill AVRs that can power 4 ohms with no issues?

Magnepans, like almost all planer speakers, are very inefficient, like 83 dB/1W/1m (the 86 dB on their website is for 1W into 8 ohms, not 4). And they are 4 ohms, albeit a fairly benign 4 ohms (no big impedance variations). Thus they need relatively high power relative to conventional designs hitting 90+ dB sensitivity.

That said, I think a lot of folk want more power than they need.

A lot of AVRs can handle 4 ohms; the THX spec requires 3.2 ohms, after all. Some handle it better than others...

Currently, my MG II's are being powered by a 10 year old 100 wpc marantz AVR. I have some 4 ohm EPI's with a 100 wpc JVC receiver. I can play them as loud as anyone can stand with no problem. The maggies are in a large open area. Probably 6000 ft^3.

The thing that people fail to understand about impedance is they require more power for a given volume, but at the same time, amps can deliver more power to lower impedance speakers, so it's somewhat of a wash. It's not an exact linear relationship, but it's not too far off.