Best sub design to go with maggies?

[elawton]

Hello. I'm a newbie on this site, loving all of the information I've been picking up. Amazing stuff here to help me do my HT right!

I'm in the middle of designing and constructing my HT myself. I hope to post an outline, photos and updates on my project later on elsewhere on this site. I'm really excited to get it done.

I'm not an audiophile (yet) because I lacked the budget and the space for what I want, but those problems seem to be solved. I love doing projects myself (I built my own in-ground pool with waterfall), so I'm not daunted by a challenge.

What I'm struggling with is the right pairing of a subwoofer design to go with a pair of magneplanar MG10's (maggies) I'm going to buy from a friend. Maggies are well-known to be excellent speakers but they are weak on the low end because of their unique ribbon design. They must be paired with a good sub.

My HT is 14 X 28, height 7.5 ft. I have not yet started construction on the stage and proscenium at the "business end", so my options are still wide open as to whether I go with a sealed, ported, LTT or infinite baffle sub, not that I fully understand the differences. Wiring and electrical are not a problem for any location as I have laid it out with 16g and an outlet to the stage from my equipment location in an adjacent office. I have access to virtually every point in the room.

The room will be dual purpose HT and game room. I have a couple of teenaged daughters that want to use it for parties. My wife and I love watching movies, so the system will probably be 50/50 movies and music.

I'm looking forward to trying out the maggies because I've read that they're great for music. I'm a bit unclear what might be involved to use them in a HT system (I'm wired for 7.1), but that's another topic. I used 4x8 sheets of 1/2" cement board for the ceiling and walls, so it's a pretty "live" room at the moment and I'll have to do some room treatments of some kind, again another line of inquiry. The floor is concrete. I'm putting in an insulated sub-floor this weekend.

I'm hoping to get advice from this forum as to the preferred sub design for my situation. I'm leaning toward an IB design based on what I've read on this site, but I'll have to think about how I could do that. I've got a good size crawl space below the stairs adjacent to the HT. I also need to build a closet perpendicular to the stage to enable access to a 2nd floor drain pipe and cleanout that I've surrounded with sound bats and cement board.

So I'm thinking I could incorporate a stack of sub drivers in that corner (volume available for enclosure 2 x 2 x 7 ft) next to the stage, which could still give me access if necessary to the pipe cleanout. Next to that I could build the closet to store a treadmill.

I just don't know if I should be thinking of porting it to the crawl space behind or into the HT room, or whether that volume is big enough without worrying about a port.

I was also intrigued by the thread about putting the IB in the stage, but I don't think that's an option for me. I don't want my stage to be more than 1 - 1 1/2 feet high because I want as large a screen as possible when I upgrade to a HD ceiling mounted projector. The maggies are also very tall (6') and I need the vertical height. Plus I don't want to put the sub in the stage if it will create vibrations affecting the maggies.

I spoke to a lady at Magnepan if they had any advice on matching sub drivers for their kind of speakers. I've read that the sub must have a fast response because the maggies ribbon technology is very quick and the subs have to be able to keep up. The Magnepan lady confirmed this and told me that although they can't recommend specific drivers, they do advise that drivers of no more than 10-12" are best paired with maggies because bigger sizes can't keep up. I'm thinking of perhaps a stack of 4-6 12" drivers would be pretty cool.

So in addition to the enclosure design, I'm hoping to get advice on good, inexpensive 10-12" drivers (tempest?) to match with the maggies.

Here's a link to the maggies I'll be buying from my friend - they are not manufactured anymore.http://www.integracoustics.com/MUG/M...0QR_Manual.pdf

Thanks in advance for any advice!

(PS - thanks for the thread on "what I wished I had done differently in my HT". It gave me the idea to put in a conduit for buttkickers in the subfloor if i want to do that in the future. I hadn't thought of that)

Eric

[Geoff St. Germain]

If you have an adjacent space large enough for the space requirements of an IB subwoofer then I think that it is one of the better ways to go. It doesn't take up any space inside the theater room which can be a nice thing for large subwoofers. Right now there are a number of IB drivers available that offer very good performance for the price, especially the Fi IB 18 which can be picked up for $209 each of $199 each for 4 or more.

I'm sure you'll get a number of other suggestions, but if I were building a room with a suitable adjacent space, I would probably be ordering four of the Fi IB 18 drivers.

[superchad]

With those Maggies I would do 2 8 or 10 inch sealed subs for fast snappy bass with music down to 30HZ or so and add a larger unit or 2 for the deep HT bass down to 20HZ or below, if you are going to do as few as possible you really need to take a close hard look at sealed subs so you can both get the fast bass for music and deep punch for bombs and thunder in movies. If you have the money and decide not to build the Vandersteen subs blend awesome with Maggies. I auditioned a set of Magnepan 1.6 with Vandersteen subs and they sounded very close to a Maggie 3.6 with a fuller bottom end.

[elawton]

Thanks for your comments.

From what I've read so far, I agree with Geoff that there are strong merits to the IB design whenever possible. That's why I was leaning toward that option at first.

But superchad has a good point. Using a couple of differently sized drivers in a sealed enclosure (or 2 separate sealed enclosures for each size?) make sense. I could make a sealed unit for 1-2 15" drivers for deep bass that sits above the cleanout access panel in the corner next to the stage. I should make it possible to unbolt the whole unit and slide it out to get in there. Above this, I could have another sealed box for a pair of 10" drivers that would be good for music. Hmm, got me thinking.

With an IB the bass is just as loud, so I understand, on the backside as in the listening room, which means some sound insulation is required on the other side (or a tolerant family and neighbours). I'd avoid this problem by keeping everything in the HT, which I've done my best to isolate from the rest of the house.

I've got more reading to do to really understand this better. I think I can handle the carpentry part no problem. For the electronics and tuning aspects of this project, I'm hoping to get some help from my brother-in-law who is an electronics technician.

Any other comments, eg. for or against the sealed enclosure idea, would be appreciated.

Am I correct that I'd need to run power to the plate amps, which are mounted to the outside of the subs, or could I use a separate amp in my equipment rack (or 2 amps, 1 for each pair of drivers?) Which is better? I suppose the answer depends on the drivers and the amp, right?

As you can see I'm just starting on the learning curve. I just discovered this forum a short while ago, just in the nick of time considering where I'm at in my project !! Any help is appreciated.

Eric

[mgboy]

elawton wrote:

But superchad has a good point. Using a couple of differently sized drivers in a sealed enclosure (or 2 separate sealed enclosures for each size?) make sense. I could make a sealed unit for 1-2 15" drivers for deep bass that sits above the cleanout access panel in the corner next to the stage. I should make it possible to unbolt the whole unit and slide it out to get in there. Above this, I could have another sealed box for a pair of 10" drivers that would be good for music. Hmm, got me thinking.

Eric

Superchad does not have a good point. You don't have to have 8 or 10 in. drivers for "fast" or "snappy" bass. That is an "audiomyth" and is incorrect. It all depends on the driver specs, and on the enclosure they are in. Using two different size drivers just adds another crossover, and more money spent, with nothing actually gained.

[mdrake]

I agree with mgboy! I would recommend either LLT or IB. If you build an LLT it will respond "transient response" like a good sealed sub in the upper registers while still being able to go LOW. I have a my Magnepan MMG's playing with a SONO tube LLT "EBS" sub and it sounds GREAT. I was actually told by the Magnepan dealer that the LLT is the way to go with Magnepans. When I complete my home theater I am leaning towards either an LLT or IB. I don't have any experience with IB but I love my LLT. GOOD choice on the speakers! Mine are really growing on me. I love the transparency, sound stage and detail for music while still sounding GREAT for HT.

Matt

[Geoff St. Germain]

mgboy is right. I think that trying to combine different sized subwoofers is generally a lot of hassle with very little, if any, benefit. Modern 15" or 18" drivers with their very powerful motors are not going to sound "slow". Besides, I think Dan Wiggins published a paper somewhere that basically showed that the acceleration of the cone was largely independent of cone mass anyway.

elawton, you can certainly run separate amps in your equipment rack. You will certainly get more power for your dollar using a pro amp as opposed to a plate amp.

[superchad]

The best subs for music are smaller drivers but its not my system so do whatever you wish. just because I say something doesnt make it correct and so it goes with others aswell, there is always a opposite view and opinion. You may want to ask around at Audiogon.com for the music side of things if you want multiple opinions. While bass for movies is pretty easy, its not so simple for good music reproduction which is why I listed 3 options, an idea with small drivers for the music and a large for movies, a single large sealed sub or a great example of a manufactured sub that works great with Magnepan speakers.

[mdrake]

a single large sealed sub or a great example of a manufactured sub that works great with Magnepan speakers

This is exactly the opposite of what the Magnepan dealer said. You might want to give a dealer or maybe even Magenapn themselves call and see what they suggest.

[superchad]

mdrake wrote:

This is exactly the opposite of what the Magnepan dealer said. You might want to give a dealer or maybe even Magenapn themselves call and see what they suggest.

hmmmmm I owned Magnepan, spoke to Wendell and demoed the Vandersteen sub at one of Magnepans older respected dealers and as we all know delears have opinions of their own based on individual beliefs, experience and even products they carry. I listed 3 options to think about......nothing more nothing less. Remember this is in context of optimal music performance and not simply thunder and bomb blast in movies which is why options need to be considered and my ideas where in the spirit of helping the original poster. This post hints at a sort of "gotcha" mentallity which is off base.

[mdrake]

spoke to Wendell and demoed the Vandersteen sub

What did Wendell recommend?

Another option might be the new sub Magnepan is working on. When I talked to Wendell he thought it should be shipping within the next 6 months.

This post hints at a sort of "gotcha" mentallity which is off base

Being that I was searching for the same answer that the original poster asked and I felt I could be a benefit as I was in the same situation.

[mdrake]

This thread discuss the benefits of going LLT vs. IB. It might be helpful in making your decision.

[superchad]

I would really look into that new sub Magnepan is rolling out and am curious to see it, there is little doubt that it should be tight and fast to blend with the Planars. If nothing else its design may inspire a recipe for DIY.

[elawton]

Hey, thanks very much mdrake, superchad, Geoff St. Germain, and mgboy.

I knew I've got a lot more reading to do, but you guys have helped point me in the right direction. I appreciate the advice and links.

I'll be back once I'm closer to understanding LLT's and IB's, and what I can achieve with smaller drivers.

Thanks again

[mayhem13]

I would take the approach Martin Logan does with their planars. 2 sealed subs each with a 12" Dayton RS and Oaudio 500watt plate amp for headroom. Use the speaker level inputs on each and cross the mains at 100hz or so. For Ht use, go with an IB setup from your LFE output. This setup extends your left right mains low end for Music and reinforces you overall low end spectrum for HT duty. The Dayton subs are praised for their extremely low distortion and with 500watts of headroom, no THD introduced from amps. Very clean setup that covers all of your needs.

[mdrake]

For your specific situation, I think there's a third element to consider: radiation pattern. I've found that systems with a single point bass driver and panels tend not to sound right, except at a very specific (and small) part of the room.

WOW, that is a very interesting and something I had never considered!! How did you figure that out?

Matt

[mdrake]

Mmmmm that really gets my wheels turning. So, would a dipole woofer line array be the best of both worlds for panels. It would lessen the effect of standing waves from both the side walls and ceiling and still give you the benefit of a line array. Maybe something along these lines only in a line array.

Matt

[superchad]

Are you guys bored with attacking me yet for my opinion and idea or is the wolfpack hungry??

[superchad]

I want to qualify my last remark, I think it was a bit harsh looking back at it today I am disabled and my health was an issue yesterday so I think it affected my mood. I again gave a few ideas I had and nothing more and doubt I will jump in with ideas on this issue any longer. But I offer that I am sorry for my last post.

[Warmon]

DS-21 wrote:

So as a crude but surprisingly effective measure of a given driver's bass sound quality, look for the lowest possible Le/Re number.

Interesting observation. Do you mean Le divided by Re? Got any theories about what cut line to use as a rule of thumb? If Le is expressed as [1khz/20khz] 2.53mH / 0.99mH, what do you use? This particular driver is DVC with Re 1.6

[mdrake]

I want to qualify my last remark, I think it was a bit harsh looking back at it today I am disabled and my health was an issue yesterday so I think it affected my mood. I again gave a few ideas I had and nothing more and doubt I will jump in with ideas on this issue any longer. But I offer that I am sorry for my last post.

I just figured you where having an off night, we all have those.
It shows real guts to apologize and I am impressed. This is a great board with great bunch of people.

Matt

[icenoir]

Hi-
I have 1.6 QRs with external XO, cc3, and maggie surrounds. I decided to go with the Rythmik 15 sealed design, which i finished about a month ago.
They sounds amazing, with great extension. Plenty fast. huge upgrade from my ACI titan 2 sub it replaced. (the Titan is noted for matching well with the maggies)
Strongly recommend the Rythmik 15.

[mrogowski]

If its not too late, I suggest looking into an open baffle sub for your Maggie's. Open baffle designs offer an extremely seamless integration with any speaker system, and considering you are dealing with planars, I (personally) think you need as much assistance with this part as you can get.

Open Baffle subs like anything else, do have their drawbacks, so weigh the consequences accordingly. There is a fair bit of info out there and other like-forums speak of the design fairly regularly.

DS-21, with all due respect to you, there has not been *any* concrete evidence that fast and snappy bass (subjectively or not) results from lower inductance in a subwoofer. This argument has surfaced way too many times in this and other forums and has been kicked around more than a dead horse. Unless there is empirical evidence from an accredited organization such as IEEE or even the AES showing that a reduction in inductance in a subwoofer's passband leads to said benefits, it is merely conjecture.

If on the other hand, said evidence has actually been released (and I don't mean that magic Adire paper talking about inductance in midrange drivers), then shoot me a link to it!

Best,
Mark

[iasonas]

Hi guys! Could jay's observation be explained somehow if we consider the amp? I'm talking about the distortion produced by the amp if asked for more current: is it possible that the voice coil resists more to the flux of current if the resulting magnetic flux is higher? But then again, this has to do with the magnet's strength (don't really know the units for magnetic flux).
Not really sure if it makes sense at all, it just occurred to me as I was reading the discussion, what do you think?

[Ricci]

Are you talking about back EMF?