[josh358]

i'd be crossing over at 60-80hz - i'd be wery surprised actively if crossing over the maggies in the 60-80hz range did not improve them quite a bit, for the reasons i mentioned earlier.  i wouldn't worry about room modes, as dipole subs load the room in a more benign fashion, and as they're separate from the mains, you can locate them for least room interaction.  and, for the price of the fathom's, you could buy four of the gr-research iterations, and really smooth out the room modes. 

doug s.

Agree about dipole subs not exciting as many modes. Which would be a serious consideration for me if I were planning to cross over at 60-80 Hz., as you are. But for my installation, I'm thinking a 30 Hz crossover, which with a steep slope isn't going to trigger the modes in my room. If I were crossing over higher, I'd definitely go with dipoles.

Because of my room configuration, I've been leaning towards GR drivers in an infinite baffle, but I'm very far from needing to make a final decision, or even knowing whether a sub would be worthwhile. The Tympanis are going to make killer bass in my little room, in fact, I'll have to EQ them down.

[SteveFord]

Just how small is this room you're planning on wedging the Tympanis in?
I have this vision of your having to enter the room sideways so you can sit in a chair.
I haven't heard JL Fathom subs but I'd go with RELs as I have heard them and they work well.
Doug s.,
I wouldn't cross over that high with Maggies as you just need to fill out where they fall off the map.  The bass that they do have is very good.

[josh358]

Just how small is this room you're planning on wedging the Tympanis in?
I have this vision of your having to enter the room sideways so you can sit in a chair.
I haven't heard JL Fathom subs but I'd go with RELs as I have heard them and they work well.
Doug s.,
I wouldn't cross over that high with Maggies as you just need to fill out where they fall off the map.  The bass that they do have is very good.

LOL, not far from the truth, it's only 13 x 14, though acoustically a bit bigger because of a large opening to a hall:



And to make matters worse, the speakers have to clear a projection screen.

Paradoxically, the IVa's are a better choice for the room than the single-panel Maggies because I can use them in split configuration with the mid/tweets in front (only 18" wide) and the woofer panels behind, touching the side walls. Here's a picture of someone's split IVa installation:



Otherwise, I wouldn't be able to use anything much wider than an MMG, for fear of blocking the projector or getting them too close to the walls.

Fortunately, it's a dedicated room, so I don't have to worry about turning it into a forest of speakers. The problematic acoustics are another matter. I was hoping to put the mid/tweets about where the MMG's are in my photo, but I couldn't get the MMG's to image properly with the mantle behind. The only way I can see to do it really right requires me to sit in the fireplace!

[doug s.]

Doug s.,
I wouldn't cross over that high with Maggies as you just need to fill out where they fall off the map.  The bass that they do have is very good.

i am not saying the maggies do not have good bass.  but, if you actively cross them to good subs, the bass will still be good, and the maggies will be better above the chosen x-over point, as they will not be as stressed...

imo of course!   

doug s.

[medium jim]

Doug:

I agree, and it allows for the use of tube amplification in the moderate wattage range. My monoblocks are 40 watts in triode and a good amount of the time I am in triode thanks to relieving the Maggie's with 2 subs x/o'd at 80hz.

Jim

[Freo-1]

Makes sense to use sub(s).  Good recommendations.

I owned Acoustat Spectra 33's for many years, and did much the same thing to get the best balance between the panels and the subs using a moderate powered tube amp.

[95Dyna]

Well, this has been very interesting and I'm very grateful for all the advice and input.  It seems there is no real consensus with many being in the "seamless integration to the JL's is easy" to "there's no way to seamlessly integrate them to a planar" camps. 

James battle cry is proven spot on.  I'll have to get the dealer to set it up and see what's shakin'.  The demo is everything.

[firedog]

The Maggies have very good bass. Many pop, jazz, and rock records don't have actual bass below 40hz, so the Maggies aren't lacking there.

For classical and some of the other records that do have very low bass, the 2 subs are a good idea. I'd also cross them over at the rolloff- lowpoint of the Maggies, not above. With subs, you don't wan't to "hear" them, but you want to notice the difference when they are on, if you get my meaning. The JL's are great subs and the DSP functions will help you get the best sound from the room.

Important to try to measure your room as best you can. Some of the software on the market that will let you "see" the response of your room before and after can help getting the best results.

[Robin Hood]

So from my perspective it comes down to blending. There are some people who say they've never heard a dynamic woofer integrated transparently with a planar, e.g., Jonathan Valin and Wendell. (Well, me too, but they've heard a lot more combinations than I have -- I don't consider myself an authority on the topic!) So that's my concern. With the MMG's, it wasn't much of an issue for me, since they really did need some help (though I think Dawnrazor was just saying that he usually leaves his sub off for that reason). But the IVa's are good to 30 Hz or so, so a sub isn't as important.

I would agree that with the IVa's and 20.6/7 subs are not as important. All other Maggies need help for bass frequencies below 30 or 40 Hz. Full range speakers used to be defined by 20 Hz to 20 kHz +/- 3dB. Speaker systems whose low bass frequency is only 30 Hz or 40 Hz leaves out important bass octaves of music.

Very few people would argue that Maggies with true ribbon tweeters whose high frequency extends to 40 kHz is not a significant plus over speakers whose top end is only 20 kHz. Why would anyone waste bandwidth suggesting that speakers whose low end of only 30 Hz or 40 Hz is enough?

Perhaps if Magnepan ever brings back an Anniversary Edition of the Tympani IVAs we will be closer to the ideal. I am sure everyone here knows that the Tympanis have the best bass period.

Another possibility would be if Magenpan developed a subwoofer panel modules or SDWMs. I wonder what a SDWM would look like?

[doug s.]

...I'd also cross them over at the rolloff- lowpoint of the Maggies, not above. With subs, you don't wan't to "hear" them, but you want to notice the difference when they are on, if you get my meaning...

my only comment regarding this, is that when i went to an active subwoofer set up w/outboard x-over and a pair of subs that were -3db at 17hz, my speakers at the time were -2db at 20hz.  the improvement in the quality of the bass was substantial.  you didn't "hear" them, but you certainly noticed the difference, if you get my meaning.     and the quality of the mains' upper bass and lower midrange, due to them being crossed over at 70hz, was also a nice improvement.  everything was improved...

ymmv,

doug s.

[berni]

Iam also thinking about giving my 20.1 some support down under in my relatively large room.
Having a advice from Soulsonic constructor to build two cardioid dipol subs, which will blend perfectly with Maggies.
Having them crossed at 30Hz, with a rather  not steep XO, to use the best of the signal and chossing a 18"driver that perfectly fits with this demands. There are some of great drivers for infinite baffle with large excursions, not heavy membrane, low Fs...

Having them behind the planars will not be my choice, they must be near to the listening position.

[josh358]

I wonder what a SDWM would look like?

Very big!

That's the problem with dipole bass, rear wave cancellation means that you need a huge baffle of you want to go deep with slam.

I've never seen a folded planar dipole woofer, though, that might be one way to solve the problem. You'd lose the cool slim form factor and cabinet costs would increase, but on the other hand you might get something that could fit in an ordinary room. Design it to fit against the wall like a DWM, that way you double the effective baffle size.

[tberd]

 My reply to this is of course the dealer recommends the JL gear. It's called sales commission.

 You guys need to check out the GR Research subs. You could have a wall of subs for less than one JL.

tberd

[rw@cn]

Logan Grottos are nice little gems. TBI subs make great music subs but you will need amplification.

[bakufu]

i'm running a pair of open baffle speakers from emerald physics in a large listening space.  i waited a year before taking the subwoofer plunge.  i was less interested in punching a hole in my chest than i was in providing a foundation for the music.  (my setup is strictly audio.)

last week i added a pair of subs from funkaudio.ca, and they do exactly what i hoped for.  in fact, my expectations were exceeded.

i recommend that you speak with nathan before making any final decisions.