Maggie owners (past, present, future) what do (did) you love and or dislike about them?

I've always owned dynamic speakers, but I'm ready for something different. I remember about 15 years ago auditioning a pair of Maggie's at a small shop on the Plaza. Don't remember the model but I was astounded by the clarity. Couldn't afford them then, had 2 kids in college. Presently own a pair of Monitor Audio Gold 300's and they're very good speakers, but I've been reminiscing about the clarity of those Maggie's and I want a pair of the 3.7i's. Those of you who have experience with Maggie's let me know your love (hate) relationship with them. My room is 17 x 15 with a sloping ceiling up to 10 feet. Is that enough room for the 3.7i's to perform at their best?
Owned Maggie’s back in the day. They tend to give one audio nervosa! 
The positioning of the panels is always crucial...
and they were very difficult to drive. I always felt that they really couldn’t push much air and were somewhat restricted when it came to dynamics. OTOH, when all cylinders were firing, they were a very nice sounding speaker with great ability to portray strings and mids. 
I recently heard the new 30.7’s...
very impressive indeed, with a surprising amount of dynamic jump and decent bass response, but they need a very large room, and a stout amp upstream.
LOL, audio nervosa. I believe the majority of us are afflicted. You say they were hard to drive, what amp did you drive yours with? I have a Primare A32 amp capable of delivering 400W per channel to 4 ohms. Adequate?
Your Primare should be adequate. Barely, lol,
i was using a Hafler ss amp, can’t remember the version, but it was his biggest model. Didn’t sound that great, but we are talking back in the day.
I've owned a few sets of Maggies over the years. In the late 70s I owned a pair of MG1s, then a second pair running side by side. Double Maggies were all the rage then. I was driving them with a diy class A amp that delivered about 80 wats per channel and they sounded pretty good for their day. 

I switched to a 3 way dynamic speaker because I wanted better bass and better slam. 

A few years later {early 80s), I bought a pair of Tympani IVs along with a pair of Entec servo controlled powered subs and was driving them with a Levinson ML3. This was pretty state of the art in those days and they sounded pretty impressive. I was literally using them as room dividers between my living room and dining room so there was about 15 feet behind them and they were firing into a 18 foot wide by 23ft deep room with a two story cathedral ceiling. With this much room to breath, Maggies do quite well. 

They are very low distortion since there is very low intermodulation, and they are very fast, particularly in the mid-range and high frequencies.  Where they fall short is in dynamic slam and imaging precision. The image they present is unrealistically large with not as much specificity as speakers that acts more like a point source. More like a wall of sound. 

A few years ago, after owning several different dynamic driver speakers, I bought a pair of 3.6Rs for my home office, driven with a Krell FPB300. The room is 13' x 14' with 8' ceilings. I was never happy with the sound in this room. I couldn't get the speakers far enough from the walls and from the listening position to get then to sound as good as I'm sure they are capable of. I think if I had more flexibility with acoustic treatments on the side walls at the first reflection points, I might have been able to get a little better sound, but I think my room is just too small for these relatively large panels. 

I replaced them with Goldenear Triton 2+'s which do a lot better in this room. I think in the right room, I might have preferred the Maggies, but in this room, the GEs were a big improvemennt in almost every way except maybe top to bottom coherence. 
From 1990 until 2014 I owned SMGa, 1.7 QR, and 3.7R.   What I loved most was the ribbon tweeter in the 3.7.  In my experience, no other tweeter can touch it in terms of extension while remaining utterly sweet.  

Overall the 3.7s were great speakers.  I moved on because of placement problems-- they are not easy to integrate into many rooms-- and due to amplification requirements.  I know there are those who drive Maggies with tube amps, but in my estimation they are designed for solid state.   Maybe I could have gotten what I wanted from a big Pass Labs amp, but they ain't cheap.   I'm locked into high impedance high efficiency designs at this point.  But I sure to miss those ribbons!
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Have owned several pairs.MG 1's , MG2's and 2-b's. When you get them right they are great. I looked at the .7 and 1.7's last year but  I am in a small room now, 13 x 12 and low power ( Manley Stingray ) so they are a no go. I have moved on to OB for a just as an " intriguing " sound. Check out Spatial Audio Labs. OB's stopped my Maggie obsession.
I’m one of ’the 20.7 will be my last speaker’ guys. Moved from 3.5 to the 20 many years ago, which was a huge step up. Going from the 20 to the 20.7 was more subtle, but still worth it. The few minor issues I had with the 20 (ribbon tweeter quite a bit faster than the rest) were solved with the introduction of push pull quasi ribbons for both mid and bass drivers. There’s less need to compensate between drivers, which enables the use of a much simpler crossover. They're now much more ’of one piece’.

Despite these changes they still have low sensitivity, so the need for a lot of power has remained. Think at least 300 watts at 8 ohms, preferably with the ability to double its output at 4 ohms. Smaller models may need less though.

Thanks all for the input. I'm not in the market for a new amp. The one I have now does 400 watts into 4 Ohms. @ jazzman463, thanks for broadening my horizons. Before your post, I'd never heard of OB speakers. I'm liking the price quotes but so far haven't read a lot of reviews. But what I have read, sounds really appealing. Their size and look are also pluses. Will have to do more research. Which model do you have and how is it's sound stage, imaging and timbre of voices and instruments?
Mewsicbuff, your room is perfect for 3.7i's. Maggies are an extremely easy load. They just require a lot of power. I like to see 200 watts/ch.
You should start with them 3 feet from the wall tweeters to the out side and toed in just a little. You measure your triangle from the tweeters.  If the bass seems a little tubby move them out to 4 feet. Dampen the wall right behind the speaker with acoustic foam tiles.
If you require more punch get subwoofers. 
You are going to love these speakers!


Own a set of 1.7i. Drive it with a Pro-ject turntable and differential Emotiva gear. Pros are clarity, sound stage and Dynamics. They sound great even when out of position but it's obvious they are out of position. They really only "sing" when you have them calibrated to about a 3ft w x 6ft h x 1ft d window. They draw monster current and need beefy amps that can handle the draw. They love AB and don't respond well to D. They make a lot of sound but don't really dominate a room. They really need a well-dressed listening room, and need the room to be a bit live and they have to be far away from the rear wall because they are dipoles. They need subs unless you get the gigantic ones, which need even more power.
They're a gimmick but I use them every day as generic living room speakers and they sound amazing. And, when I get some good source in, grab a glass of whiskey and get them "in position," it's a serious treat. Despite their foibles they really are an incredible thing.
I have had Maggie 1.7i’s for a year or two, driving with solid state Bel Canto REF500m monoblocks, 500w @ 4ohm. They go very well together, and the speakers are my favorite that I have ever owned. Accurate and sweet! Looove them. 
Mewsickbuff I am A dealer for GT Audioworks Planar speakers that is a must audition. They are a full range planar design with no crossover, pure copper traces and can play at much higher spl’s with way better slam and dynamics. The attached video is the reference model usually reserved for large rooms.
But a lot of our customers have opted to buy the speakers and mate them with the 2-12 inch open baffle subs per side.
Cones vs thin film speakers?  So why not both.  I have a pair of MGCIIIs, MGAs, MG1Cs, MGWs, MG on walls, DWMs, and a MGCC2.  Not all work.  The IIIs were sold as only needing a pair of ribbon tweeters needing  a rebuild.  The midranges were also shot.  The MG1Cs were given away, their dog knocked them down, and back to me they came.  The on walls are awaiting new thinking for the highs and lows that are missing.  One MGA sits under the tv, serving as center channel.  The MGWs alternate with my newest speakers, Martin Logan Clarities.  The DWM's sit inboard of the mains whether MGW or ML.  Side by side the MGWs have a tad better/more midrange and presence.  The Martins have the superior highs and 8 inch cone bass.

        I like Maggies.

I use various 200 wpc at 8 ohms amplifiers, all ss.    A DBX two way crossover set at 75.  Two 10 inch Kickers, each in a sealed 2 cuft box.  A 12 inch Kicker in a 3 cuft sealed box.  A Denon POA6600 drives the subs.  It has taken years to put it all together.

Mewsic you can try some of the Magnepans direct from the company.  Starts with the LRS model, and you can return or trade up within their policy.  Subs are a must.  If you are looking for speakers that reveal and do not conceal, these sound close to real.  If you are looking to peel the paint off the walls, stay with cone speakers for high spls.  Happy listening in your quest.
To be honest to this day they have cheap frames which flex and lose detail, mys stands help a lot, as well as rubbish cheap Xover parts which I always 
upgraded as well as UCB better quality fuses, get rid of the junk 
jumpers and put quality jumpers in .
Peter Gun in Pa always made Maggie mods great  Magna stands.
I only had the MG 2a's, which I loved owning, but IMHO, Maggie's are speakers that often sound better at the store or at shows because their reasonable price makes them attractive to those who don't allocate the funds for the amps that they need.  That was me. I had 100 wpc Sansui BA-2000 amp, but not the right 100 wpc.

I went onto Martin Logan Quests, which were more ballsy,  but have moved on to 40 inch tall dynamic floorstanders because instruments and voices have the right "in the room" size..  A triangle is believable in size as well as sonics.  Same for singers, drum kits, trumpets and the rest.  To me, you lose that proper sizing from five or six foot diaphragms.
I am a Maggie owner (past,present, future). If you go to the Magnepan website and look at the 3.7i section the second picture down shows a system with a pair of Red 3.7i ; that IS my system. The 3.7i are the third pair of Maggies I have owned through the years. They started life as 3.7 and were factory upgraded last yeat to 3.7i . I have also owned at least 30 pair of other speakers as my mains since I started 40 years ago including Infinity IRS, Carver Amazing and Martin Logan Summit plus many big name Dynamic Speakers ranging from AR's, Klipsch, Ohm, B&W etc, etc, etc.  and seem to gravitate back to the Maggies each time. The Maggie's ribbons create an almost ethereal reality to vocals and strings that I find compelling. With the right power ( I use an Indy labs Aragon 8008 at 400 wpc) they can light up a room and produce excellent dynamics as well as, or sometimes better than many other speakers of similar efficiency. I have a small sub a Definitive Technologies 4004 to help the very lowest frequency range (below 40hz) the speed and tightness of the sealed passive ported Deftech matches well with the Maggies and was easy to integrate. 
My only negative I can mention is the need to spend some time finding the ideal placement which is not necessarily more difficult than many other speakers, just different.  In the future I have my eyes on 20.7i but I don't have a compelling need to change since I find the 3.7i to be about as good as it gets.  
I owned 3.5Rs for 2 frustrating years. I tried biamping with W4S MC 250/500 + active XO and subs but could never get what I wanted from them. I replaced them with Emerald Physics KCIIs with Clarity cap and WireWorld XO wiring (which I still have). I have gone through 2 Emerald Physics 100.2SEs, Audio Alchemy DPA-1 (excellent sound but needed more power in my big room, PS Audio M700s, which I did not keep only because, at the time no one bought my DPA-1, so the M700s moved on, and finally (yeah, right-lol) I caught wind of Ric Schultz newest amp the EVS 1200. It checked all my boxes; dual mono It uses 2 of the newest IcePower 600 modules= 1200 watts! to which Ric sprinkles his pixy dust. While it sounded good from the get-go, it took about 50 hours to start coming on strong, and even better at ~ 100 hours. My guess is it is a great amp for Maggie owners (glorious mids and bass), or any speaker owners. My KCIIs, which remind me of maggies in their seamlessness, are too small for my large room. I can’t wait to hear it with my EP 2.8s (dual 15" woofers), which should be here by the 30th. Oh, and it’s only $2200, 30 day money back !!!
OK, as former dealer, everyone here knows I am a Maggie supporter in every possible way.

However, as I always end my posts, it depends upon YOUR ROOM, which everyone knows is the most important variable in any system.

SO, bring them home and listen and see what YOU think.  Personally, they were a revelation to me when I first heard them in my shop in 1973.

We had at least 40 different brands and many models of each brand in the shop and I had to listen to ALL of them to be able to sell them.  Except for Fulton 80 and 100 box speakers (not available for many years now except used on ebay, etc.) there were NO boxes that were even in the same universe as Maggies. 

Today, designers have MANY 6" tall speakers--wonder where they got THAT idea???--and boxes have come a long way, so I am no longer qualified to judge.  Having typed that, I can tell you that Maggies STILL add nothing to the sound of your gear, so set up what you have/wish to buy IN YOUR ROOM and make your own decision.

As for placement, YES, very critical, which is why you need a good dealer who understands room acoustical properties to help you with this.  Also, if you prefer the chest-thumping bass from rock songs or classical orchestras recorded properly, you can always add some subwoofers if that is what you like.

Maggies are the best, as I always post, but you have to like them in your room first.  Enjoy the music...

1+ richopp. I would like to add that the 3.7i might have the best cost to performance ratio in the industry.
I know that these discussions can sometimes get testy, well, I am not here to do that but.  Maggies are the best speakers that I personally have ever heard.  I have always wanted to listen  to a pair of ESL's , but have never had the chance.  I owned and listened to a Pair of MG-IIBs for more than twenty years, only changing when I moved into a new house where there just was not enough room for them.  I was going to sell them, but never put them up for sell --still hoping that one day I can use them again. They were powered by an Audire amp rated at 100W/ch at 8 ohms, and 150W/ch at 4 ohms.  The MG-IIBs offered a purely resistive load of 6 ohms -- no complex impedance to strain your amp.  You just need a well built amp, capable of putting out ample current. I know that many will say that times have changed and the current models are better and I hope that they are, but the only thing that those speakers ever needed was space, power and a little more base - with the right amp, only a little more base.  I once auditioned a pair of Vandersteen 2Ce speakers because I had heard how good they were and walked away, unable to give up the clarity of the mid-range and upper base that the MG-IIBs offered. By the way these guys are built like battle ships, no problem with anything.  The dealer pushed one over once onto a concrete floor and it wasn't hurt, just to prove the point.

Hey Mewsickbuff,

My first OB's were Emerald Physics CS 3's   ( Clayton Shaw design) and loved them in that small room. The down point with them was the separate equalizer/crossover prevented me from using my Manley Stingray for power. After much research ( lots on line ) I ordered a pair of Spatial M5 Sapphires. Still have not received... I trust Claytons design , check out his past work. Call him , cool to talk about his work. I find OB's to be like loud Maggies with great bass. I do believe they even have better imaging. They truly put the musicians in the room. Have fun with your journey, I have been on mine since 1973 .

I have had multiple Maggies over the years, SMGa, .6, MG-12, 2.7, currently 3.5s with Mye Stands rebuilt by Magnepan last year.  I have also had many dynamic speakers, Celestion 15, NHT SB-2, Vandersteen 2c, Vandersteen 3A Sig, currently Totem Mites on my desktop.  My observations relative to your questions:

1)  Maggies have compromises, as do all speakers, depending on the persons, the benefits of Maggies outweigh the downsides.  People seem to either love them or wonder what the fuss is about.  

2)  Your room is large enough.  I ran a set of 2.7s in a 14x17 foot room for years and they were wonderful.  You should treat the room, GIK acoustics is a great source of help and reasonably priced treatments.  

3)  You amp has enough power, barely.  The larger Maggies want more power.  I found with my SMGa's, .6, and MG-12s, about 200w a side (into 4 ohms) got the job done.  The larger maggies really like 500w/ch a side or more.  You might want to consider 1.7s if your sticking with your amp, you are what I would consider on the edge.  

4)  They are big.  The 3.7s will dominate your room.  
I have had 3 sets of Maggie's with 1.7i's the last.  I have struggled with setup for 4 years until quite by accident had to push them into the wall against windows that had two layers of heavy curtains. Somehow everything came into focus with all the details I had been looking for. A fluke or have I stumbled onto something? 
It is likely the dampening of the backwave by the heavy curtains helped. I have found that if maggies are closer than about 4 feet from the wall behind them, the wall needs absorption, or they get shouty.
No audiomaze you just killed the primary reflection off the front wall. I tell people to do this with acoustic foam tile. You did it with the curtains. All roads lead to Rome! 

I like big soundstages' and have had 1.6's for 18 years, since we moved into a house with a large finished basement. The room is approx. 30' x 60' x 8', irregular in shape with a wall at one end 45 degrees, where the speakers are placed, to the rest of the basement. Drive them with 2 Arcam 10P's at 175 W into 4 ohms. Spent a lot of time fussing with positioning to find the best available imaging to my ears. Ended up 50" (not 49, not 51 ;>)) from the back wall and 93" between centers which points them at the intersecting walls to the 45 degree wall. Listening couch is about 10.5' from the speakers. The speakers are towed in to shoot just outside my shoulders. Clarity and imaging (most of the "soundstage" was off the back wall behind the speakers) were very good at modest to loud levels, although there was a bit of bass boom around 80 to 120 hertz (guessing). I wanted to try cutting down on the reflections so put some fiberglass/foam panels up on one of the side walls furthest from the speakers. Damned if the bass boom didn't unexpectedly disappear. Made two more "major" changes in all these years, one good and one bad.

The good - Wanted to experiment to get the most out the system on the cheap. Gutted the stock passive crossovers, rewired a different set of binding posts to  the panels, and added a used Bryston 10B electronic crossover. What I thought sounded pretty good got better in every aspect. Well worth the time and money and I'm cheap and lazy.

The bad - After adding the crossover I changed from a 24" crt on a stand between the speakers to a 50" plasma on the stand about 2.5' from the back wall. Really messed up the soundstage. Now instead of spread across the back wall with pretty specific vocals and instrument placing it's mostly outside the width of the plasma TV. Oh well, live and learn.

To sum up - I have a wall rack for the TV and hope, when installed, that will restore the nice imaging. I could use more power. If I crank the little Arcam's up to ear splitting (say I'm outside or upstairs) they will go into protection mode after awhile. 2 Pass Labs 150.?'s would be ideal, but at $13K delivered new, it is a bit pricey for me. 2 Parasound A21's used at $4 K +- would probably work. I really enjoy everything about the 1.6's (even with the messed up soundstage). Yes, they work better in a larger room, need power, and a little work on positioning but well worth it. Some day I might upgrade to a 3.? or 20.? if I could find them used. The only box speaker I might try would be some form of line array that would mimic the 1.6's big soundstage.

Hope that helps and good luck with your quest.

BTW - no problem with delamination after 18 years of pretty loud playing.

Jim S.
Hey Stilljim try the new parasound A21+ .500 watts @4 ohms. Works for my 1.7i's 
Seriously considering buying a pair of localish 1.7i as the price is crazy cheap.
Happy as a pig in muck with my MMGi but you never know the 1.7i MIGHT be a glorious move... or not.
At the price I think i can hardly lose, its only a 8 hour drive round trip......

Driving my MMGi with Ayre EX8 integrated and although "only" 100w it is most certainly the RIGHT 100w!
I believe your room is fine and your power adequate.  I have had 3.6 Maggies for over 10 years.  I went through a number of amps and ended up with a pair of MC501s that make them sing.  It was a journey, but most satisfying when the end is so great! 
One last thing, for me, a tube preamp also raised the bar musically with my Maggies.

If I had a big room, I would move up the chain, but I feel I am limited in that regard.

Good Luck and Happy Listening
Thanks for all the input. I'm glad to hear my room is adequate for the 3.7i's but not too thrilled to hear my amp @ 400 watts into 4 Ohms is just marginally good enough. For visual sake if you're standing in my living room facing the street, my HT is set up on the right long wall with its own speakers to either side of the TV. My (music only) stereo speakers are on the short wall with a street-facing window behind each speaker (small 4x4 foot front door alcove to the right). It's already a tight squeeze around the right stereo speaker and left HT speaker. I'm almost thinking the 1.7i's might be a better fit for my living room. I can't see a speaker almost the size of a bedroom door further dominating that space and the 1.7i's are closer to the size of my present speakers. How do the 1.7i's perform? I've read one problem with Maggies is their imaging can be unrealistically larger than life. Have you found that to be true with the models you have (had)?
@ stilljim, Sounds like you're quite talented with revisions. I'm not and wouldn't consider changing a thing, lest I damage something.

Jazzman can i ask which model of Spatial OB speakers you have, and if you have heard Nolas, how would they compare?
I've owned two pairs of Alon - Nola OB speakers and loved them, the Spatials i am unfsmiliar with but they look intriguing 
My first personal purchase was a 500 dollar pair of Maggie starters back in the early 80s. I noticed the usual weaknesses like they needed proper placement and had terrible drop off if you weren't on axis. This didn't bother me much since the speakers were easy to move and proper placement was obvious by ear. Also common complaint was lack of bass and that was true. All of that was all overshadowed by a sense of dimension and space that was orgasmic and for the price...irresistible. The weaknesses had one final addition that arrived late in life for me...very low spousal approval factor. In the end I used the credit card and moved over to Thiel but that's another story.
mewsickbuff, take a deep breath! Your amp will do just fine. 3.7i' are not all that much larger than 1.7's they are just a more imposing image but in reality do not eat up that much floor space. The 1.7's are an apartment speaker. Your room is on the large side for them. 
Next. It is not that the imaging of 3.7i's to too large, it is that regular speaker's image is too small. It is like sitting in row 6 vs row 20. Forget about a realistic image of a jazz club with point source speakers. They can just not get you close in and large enough to be realistic but 3.7i's can do it just fine. You do have an interesting set up. If there in nothing between those windows you might consider putting your TV or screen between the 3.7i's and consolidate your systems. A lot of us do that. We put a screen or large TV between our 2 channel speakers and use our Stereo for HT duty. The only thing you need in addition are good subwoofers. I personally have absolutely no need for rear or side channels and nobody who has ever watched a movie with us has related being disappointed because of such. Quite the contrary. I do use a 113" diagonal screen and projector. 

Thanks for the tip on the new A21+'s. I mostly try to buy used but I'll look into it.

I understand. I spent a lot of time over on the Planar Asylum reading up on adding the electronic crossover. The actual process is fairly easy although intimidating to think about. The only trick I used was cutting new nylon binding post plates on a laser we have at work.

I listened to what was the latest 3 series speaker of the time, the 3.6, at the dealer where I bought the 1.6's. Yes, it's a pretty sweet sounding speaker and not that much bigger than the 1.6's. At the time I went for the less costly 1.6's (as I said, I'm cheap). I think you would enjoy either the 1.7's or the 3.7's. IMO - They are pretty amazing for what they cost.

Good hunting.

Jim S.

I had mg1.6’s in my 24 by 12 by 8’ room. The room was too small for them. Not to say they sounded bad, but the image was compressed into the center. Bass was not deep, but was ,very full and rounded and quite nice. Harmonic textures of instruments sounded real. I really missed a wide and deep soundstage, I enjoyed from my mini monitors with subs biamped.

i sold them and bought the smaller Maggies. MMG i believe. Things got much better, but bass was not as full. Imaging and soundstage improved to the point where I kept and enjoyed the mmg for several years in my room. Bass was a little slimmer, and I went through several subwoofers to try and find a good match. From HSU, to Infinity servo sub, to several diy jobs. I  finally found that  Yamaha, YST, 8", servo subs mated well with them.

They are great speakers, and if I get a bigger room, I will definitely move up the maggie line.

I own a pair of Peter Gunn modified MG-12s, and I am very happy with them.  They still require a ton of power, but efficiency goes up about 3 db with a new upgraded crossover.  Placement is still key, and room is still your biggest enemy.  One of the biggest improvements (to my ears) John's (that's his real name) mod does is improve bass.  It is not the slam dynamic speakers have, but it's audible and pleasant.  Speed, imaging and soundstage also improve.  I had stock version for about a year before sending them in for an upgrade.  Difference was stunning.  His upgrade is not cheap, but is worth it, in my opinion.  Plus the looks of the custom wooden frames are beyond description.  Check it out @  Working with John requires patience, process takes A WHILE, almost six months in my case, and there is a considerable cost involved, but if you'd ask me if I"d do it again, I would in a heartbeat.  Unless he changed his mind, he'll only do 1.6, MMG and 12, read the pages.  Best of luck!
I really want to reinforce what chattaudio wrote above. The magnestands are JUST WONDERFUL!!!!! I have the 1.6's with the Jupiter caps and my friends love to listen to them.. My girlfriend said. " jeeez they sound real".
Ok they do require a medium sized room and good amplification. I have squeeked by using a Pass 30.8 , however I am convinced that I need more juice. DAMN I hate to buy a new amp. Nevertheless once they magnstands are set up :the speakers are beautiful in tonality, resolution and believe it or not bass. 
The magnestands are a great speaker!!! 
Call John and spend a few minutes with him.
Best wishes
I'm a present owner of a "past" mag- the MG III (refurbished). I purposely chose them as opposed to their immediate.successive models due to musicality and coherence. I cannot comment on the most recent models. 

You will generally need high current amp. My speakers need to be played fairly loud to get them to their potential. Close to concert level is impressive but the amp is critical. You need to get the membrane and back wave up to speed. They don't sound that great when played soft but that's not why you would get them in the first place.

To me, they excel in live complex large thick music. 

Depending on your music and taste, you may want bass reinforcement.

I second or third the favorable comments re John/ Peter Gunn/ Magnestand. Several years ago I communicated with John re diy mods. Although I have yet to implement many of his shared  suggestions, those tweaks I have made consistent with his theories have been spot on. I have no reason to doubt his favorable reviews. 
I had a pair of 1.7s that I loved.  I agree with jaytor that they could project an exaggerated image.  I think it was a Duke Ellington song in which the voice seemed to be coming from an enormous head.  I listen mostly to classical music so that effect didn't happen often.  They were superb for my type of music.
Your amp should be fine I’m running my 3.7i with 500 w into 4 ohms never a problem always sound great. I wonder how many of these people saying your amp is barely adequate actually own the 3.7i.
When I had my 1.7i i was using 240 w at 4 ohms and boy did they sing.
With Maggie’s it’s how much current the amp puts out.
I should add my room is 12x 15 so as long as you can give space behind them you're fine. I love the clarity and soundstage of Maggie's.
I agree with mljostyn, johnto and others, Your 400W @ 4ohm should do fine with the 3.7i Maggies and your room size, with care and patience in set up, should be fine
To me, the Magnapans of the late 70s early 80s, while having the detail and timber nearly rivaling the Quad, ESLs, the sound seemed a bit thin and less engaging, by comparison. With the later models (particularly the .7, 1.7, 3.7 and 20.7 models) I am very impressed. They are dynamic, with clean accurate timber and detail, yet are very full and engaging.

In my 14’W x 23’D x 10H audio room, my 1.7s do a great job - presenting a deep, wide stage with a very detailed and solid image. Augmented with a ADS sub the sound is full and musical, yet detailed with convincingly good timber. I am driving them very well with a Rogue 100W per side integrated tube amp.
IWhen moving up to the 3.7i, I may need a bit more power, but even so Mike @ mijostyn thinks the Rogue may be enough.
In my, or your, space, I believe the 3.7i would provide the same incredible sound as the smaller 1.7s but with an even larger, fuller stage.

For most genres of music - particularly Jazz, Pop, Celtic Country or Old Rock (Bob Seger, Van Morison, Pink Floyd, Fleetwood Mac, etc.) - I can not think of any speakers, at anywhere near the price, that do so many things so well, as the Maggies, when properly set up in a good room and integrated with a good sub......Jim

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@mewsickbuff Regarding the large sound stage, I agree with Mike, I've never been to a live performance where, when seated or standing 5th or 6th row, the performance didn't sound large.

Speaker placement, sometimes even 1/2" one way or another, is critical with the Maggies, Also, dampening of the front wall behind the speakers is important. In my room, after dampening the wall behind with acoustic drapes and pains taking set up, the imaging and placement of vocals and instruments is incredible and stays that way - whether standing or setting and wether in or out of the sweet spot. In spite of their large size, the Magies have a way of disappearing from the performance, leaving only the performers the music and the stage....Jim
With my .7s I find that a good solid-state amp paired with an equally good tube preamp seems to work best.  I will say that speakers do sound "sweeter" with all-tube gear, but not as dynamic.
It's all about synergy, and of course, the room is an equally important element.  My listening room is small 11x13x8 and in some ways, I prefer my old, partially modified (half-razor) MMG's  ie: they were less "vivid"  and bright.  The .7's can sound "too vivid" to me at times.  I have experimented with resistors in the .7s but that zinginess is often still present, no matter what the source is.

 Again- all is relative. I'm kinda sorry I sold the MMG's- so much so, that  I may get another pair and sell the .7s.  :)
I have owned 3 different sets of Maggies over the years.

Currently, I have a pair of MGIII. I bought them from a seller who had them in storage for a couple of decades, for $300.

I had to do some work to them, i.e. relaminate the coils in a few places, buy new socks and recover them, build new bases. On top of that, I upgraded all the caps in the crossovers (Magnepan was notorious for using mediocre parts in their crossovers) and built my own stands for them (similar to Mye stands).

As for the stands, Maggies are fairly unsupported, so they tend to move forward and backward with audio output, causing a slight amount of blurring, that is not really noticeable, UNTIL you hear a pair with stands. Putting stands on them, makes them clearer, better imaging, tighter midbass, and some other improvements.

The things I like about them: very coherent, great detail and transient response, big soundstage (width and depth), great midbass.

Things I don’t like about them: compress dynamics a bit, images are a bit larger than life (better with newest Maggies), images are not as specified as dynamic speakers.

Even though I like them a lot, I am in the process of selling them to move to dynamic speakers*.

*Yes Kenjit, even though I enjoy the hell out of my Maggies, I am still going to get something else. What a concept.
I had a set of 1.6QRs that I really enjoyed. The only reason I sold them is that we moved and the room at the new house was simply unsuitable for bipolar panel speakers.

That's probably my only contribution to this discussion -- take a good look at your listening room and how the speakers will interact with it.
Over the weekend I moved my stereo to a bedroom, 12 x 10 x 8. I know the 3.7i's are too big for this room. For the first time I plan to do some room acoustic treatment with some diffusion panels and see what happens. Without it, though, I'm enjoying the privacy. My speakers are 3 feet from my front wall and 3 feet from the side wall. I sit in an equilateral triangle which is only about 2 1/2 feet from my back wall. The sound stage is fairly wide with most music (wall to wall) and every now and then deep, but not so much high. Imaging is good. Perhaps now, the 1.7's would work best.
simonmoon, it also helps if you add mass to the top of the speaker. I made lead caps for my Maggies back in the 80's by melting fishing weights into a form. My 2+2's have a 1/4 inch thick steel plate embedded in the top. They came with a 1/8" thick plate from the factory. This is even more important for the Acoustats as there are no magnets in it's construction. For the Soundlabs you can get the Ultimate frame which is made of sand filled steel tubes. I am not sure if they add any weight to their wood frame speakers. 
+4... for the PG Magnestand Maggie 1.6’s, which I have also. His mods do resolve the weaknesses of Maggies, which are dynamics and bass - they add dynamics, bass and resolution. And yes they are best with all things acoustic - jazz, classical quartets, country, cellos, violins, guitars, piano, sax, trumpet, vocals, etc. Diana Krall never sounded better.

So... Mye stands, or similar, and upgrades in the crossovers are likely required to achieve similar improvements.

About as close as you will get to the ESL 57’s - if - acoustic sounds is your thing.

Or... you can go the Open Baffle (OB) route - Emerald Physics, Spatial Audio, Linkwitz Orion / LX521, Legacy Audio, Nola route and have the Maggie sound on steroids - with much of the same sound as the Magnestand Maggies. Most of these will cost more. Or, of course, some of the GT Audioworks planars are superb, but pricey.  I omit the Golden Ear products because, while they have great ribbon tweeters, their bass and mids are veiled - they’re really meant for home theater sounds, not great 2 channel, audiophile sound.

Most of these alternatives will do better with rock, and similar sounds.

If your into acoustic sounds, and have a limited budget, and limited room size, its very hard to beat the lower end Maggies. But for a little more, you can have most of the Maggie mids and soundstage, with dynamics and bass with the OB alternatives, with a wee bit less, clarity and resolution. Or... for a bit more you can have it all with the Legacy Audio Aeris - which almost nothing can match at any price. Your choice.