What DIY sub to match with Maggies for music??? (1 Viewer)

[Stephen White]

Hey guys, I'm pretty new here as you can tell. I've been on a few other home audio forums and just found this one. I must say this seems like a very in depth forum and I'm loving this very active diy section!!!!

Here is the deal. I have multiple hobbies and not enough money to go around, haha. I've got a set of Maggies that I use 85% music(jazz) and 15% movies. I'm the guy that likes to sit and listen to his music for an entire cd or more so the sound quality, clarity and realism means a lot to me. I've been needing a sub for quite some time but cant find anything I feel sounds clear and musical enough. When I hear a bass guitar I want it to sound like the instrument...not boom boom boom. Does that make sense??? I like the REL subs but they cost too much for me at this point. I just cant spend that kind of money, I've got too many other things I can spend $1500 on besides a sub that I've done without for over a year already.

My wife and i have come to an agreement on the sub. I can spend up to $400 on a diy as long as it can dub as a nice looking end table.

This is what might save me some money. Before I bought my Maggies I had some home theater speakers, they were the AR P315HO speakers each has a 15" sub and 500 rms watt Bob Carver Sunfire amp with a crossover. Since I have 2 of these that I'm willing to remove and use in my diy project I'm thinking I can either make one hell of a sub or 2 subs. I doubt I will use the speakers though as they are too slow, I'll prob just use the crossovers and amps. Those speakers would shake the entire outside of my house and you could even feel the vibration in the neighbors outside wall of his house!!!!! And they are sealed enclosures!!! This leads me to believe they really do have the 500watts they claim.

Anyway, sorry for the entirely too long post I'm just getting excited to start some awsome and beautiful sub project.

Thanks,

 

[Dustin B]

A sealed Adire Maelstrom would be to your liking I'd imagine. Although you'll have to find out if there is any boost or limiting circuitry built into that amp.

A sealed Tempest with the HS200 amp (gives you a 4th order Linkwitz-Riley crossover and a few other nice features for a straight music system) would be as well. But that will take you $50 over budget not including the enclosure.

 

[Jack Gilvey]

I'd be willing to bet that the only sub capable of being as free from room-colorations as Maggies in the bass will be a dipole sub, maybe based on Adire DPL12's. Not really high-SPL, though, unless you go with lots of 'em.

 

[Hank Frankenberg]

Jack, I've had extensive dialogue with ThomasW and he is of the opinion that only dipole subs are good ("fast") enough for Maggies. You know that Jon and Thomas are considering trying the Adire dipole 12" drivers in their newest experimental dipole speaker:
http://www.htguide.com/CFBoards/inde...estTimeout=500
Ala Linkwitz.

 

[Stephen White]

OK I think you guys are going to realize pretty quick that I'm not a engineer and dont pretent to be haha. I am good a building and designing things but I dont have a fit understanding of acustics and how to build a dipole sub. I guess where I'm going with this is that I'll probably need it layed out for me, like a website that has good pics and info on how to build a dipole sub.

Jack, Thanks for the link on the Adire subs, they look like they will work good and fit the budget. I'm not really looking for SPL. Dont get me wrong I do turn up the music pretty loud and I watch movies here and there pretty loud but I'm not really trying to bring the house down as I know music and SPL dont mix....at least not in my price range lol. I would much rather have a nice looking, tight, fast, realistic or rather musical sub than a spl monster (actually I've already got 2 spl monsters in the closet).

Dustin, To be honest I have no idea about the circuitry built into the amp. I have no idea how to find out either short of calling AR and hoping someone can tell me. I would have to know exactly what to ask them though as I have no clue about circuitry.

Hank, Thanks for the link. Is there a picture any where of what a dipole sub actually looks like on the inside and outside? Would it have a driver on both the front and the back or is it more of a internal thing thats within the enclosure? Kinda like the car sub boxes I've seen with 2 speakers facing each other but all self contained within the enclosure. Is it like that or am i way off???

OK, from the looks of things so far there isnt really a proven layed out diy dipole sub is there?

STEPHEN

 

[Hank Frankenberg]

Stephen, here's a link to Siegfried Linkwitz' site that has his dipole with dimensions for three different manufacturers' 12" drivers:
http://www.linkwitzlab.com/woofer.htm
Don't dig into his site too much - he's a superengineer and will lose you.
Since Adire is coming out with a dipole driver, I would be very surprised if they don't do a white paper, including design suggestions. Why don't you send them a note and ask their intentions?
A simpler approach might be to do a sealed subwoofer. There seems to be a camp that believes sealed subs are "faster", thus better suited for music.
Anyone out there heard a DIY sealed sub paired with maggies?

 

[Simon W]

(PE 297-608)+(PE300-793)+MDF => $145+$150+$30=$325
LOOK AT THIS **The Critical Q Sub-Woofer**
http://www.vacuumstate.com/sub/index.htm

 

[Stephen White]

Ok, I sent Adire a email asking if they would be coming out with any type of dipole sub kit for those DPL12's and also asking for any suggestions to go with Maggies.

You guys keep it up, this is great info. I'm reading all your links and trying to take in as much as possible!!!!

So far the only problem I see with the dipole speakers so far is that most are not very attractive looking. All the dipole subs I've seen so far would not come close to passing the wife factor. Do you guys have any pics of some real good looking dipole subs that could pass as a nice endtable???

Thanks,

 

[Kerry Hackney]

Welll, you originally said you wanted to spend about $400 and you wanted to have an "endtable" sized result. I would go with a sealed Adire Shiva or Tempest for a music only application.

One caution, this will depend on how big your room is, and how loud you listen. If you don't have your heart set on DIY you could consider the Rava as an alternative to the much more expensive REL.

BTW, I am a former MGIIA owner so I am familiar with the quality of the maggies. I think a Rava would have been my choice if I still had them.

YMMV

 

[Stephen White]

Kerry, does the $400 Rava really sound as good as the REL subs???

THANKS GUYS!!!!

 

[Jack Gilvey]

Jack, I've had extensive dialogue with ThomasW and he is of the opinion that only dipole subs are good ("fast") enough for Maggies. You know that Jon and Thomas are considering trying the Adire dipole 12" drivers in their newest experimental dipole speaker:

Yeah, Hank, I offered to send Thomas mine so they could test/experiment with them but it was too close to the pre-order deadline, so I guess they might just order some. I'm most interested in using mine in a project like that. And that kind of enclosure construction is right up my alley...real simple.
Stephen,
I'm no expert on subs, and I know even less about dipoles. The idea, though, is that the front and back waves are allowed to propogate freely, but not cancel each other out front-to-back. The simplest dipole sub would be a driver mounted on a big flat baffle, just a piece of wood. At a certain frequency, determined by the actual size of the baffle (smaller size, higher frequency), bass would begin to roll-off a 6dB /oct., so unless the baffle is really huge, some eq is required to counteract this rolloff (like in the Linkwitz design). Something like the Pheonix is also attempting to "fold" the baffle down into a more manageable size, as opposed to just big and flat. You can see in the diagram that neither the front nor the back of the drivers is enclosed.

These are, apparently, the best-sounding of all sub configs. The drivers are allowed to operate "perfectly" (free-air on both sides), as in an IB, but the wave propogation keeps the output largely free of room interaction, which is the bane of all LF reproduction.
The cost is less output due to cancellation/greatly increased excursion requirements for a given output. In a conversation with Dan Wiggins, he indicated that four drivers in a dipole config. would have the approximate output of just one of the same drivers in a vented config, if I recall correctly.
More views of the DPL12, very cool-looking imo:
http://mywebpages.comcast.net/jgilve...AdireDPL12.jpg
http://mywebpages.comcast.net/jgilve...eDPL12rear.jpg

 

[Jack Gilvey]

These "IB" drivers just posted at PE would work well in dipole also:
http://www.partsexpress.com/pe/pshow...number=295-450
http://www.partsexpress.com/pe/pshow...number=295-455
The higher-Qts might be better than the normal ~.4. In fact, Lambda Acoustics makes dipole-specific drivers with a Qts as high as .94.
http://lambdacoustics.com/drivers/DIPOLE15.html

 

[Stephen White]

WOW, Jack I knew that dipole subs werent much on spl but I didnt realize it was a 4 to 1 difference!!!! Thats alot of difference.

Thanks for the info!!!!
STEPHEN

 

[Jack Gilvey]

Yeah, the difference is about 2 to 1 when compared to a sealed.

 

[Dustin B]

Where would a baffel of the size in your picture start to roll off? And has you reading provided any reasons for why it would elliminate room interactions?

 

[Jack Gilvey]

And has you reading provided any reasons for why it would elliminate room interactions?

Not sure on that one either, but it's got to have something to do with the fact that it's the only type of sub that's not a monopole, there's only output from the front and back since the side output is cancelled. It apparently excites fewest room modes that way. There's probably info. on the Linkwitz site also. The FAQ has good info.

 

[Stephen White]

The only prob I see with the dipole above it making it look like it could be a endtable. The side is 19x13 (its listed on his site). The 13 is the height. That would be very short for a endtable unless it could be put on stands or something.

Maybe just a good tight sealed enclosure would be better for a sub that can pose as a endtable.

 

[Jack Gilvey]

Maybe just a good tight sealed enclosure would be better for a sub that can pose as a endtable.

Sure, it'd also be much easier as a first project.

 

[Dennis XYZ]

Where would a baffel of the size in your picture start to roll off? And has you reading provided any reasons for why it would elliminate room interactions?

Linkwitz has a spreadsheet you can download. For the Phoenix woofer pictured, the dipole puts out 6dB more than a sealed at Xmax above about 300 Hz. Below that the dipole starts rolling off its Xmax output 6db/octave faster than the sealed. So, at about 150 Hz, they are putting out the same dB and, below that, the dipole puts out less - 6db less per octave below 150.

Why it works is all about the power response in the room. A monopole speaker set out in the room is directional in the treble but the bass goes every direction. So, you have to pump more bass into the room to get flat frequency response at the listening position. Dipoles have more or less the same coverage - a figure-8 shape - at all frequencies so, to get flat response at the listening position, you pump the same amount of bass and treble into the room. Dipole fans will say that excess monopole bass in the room sounds unnatural. As proof, they will say walk down the hall from the listening room and see if it sounds like the band is in the room. Speakers with uneven power response will sound bass heavy and unnatural. An extreme example might be how a car sounds when it drives by playing some hip hop, even with the windows rolled down.

As an aside, dipoles aren't the only way to get even power response and they have plenty of other problems. I like the way Jim Fosgate did his listening room. He built infinite baffle speakers into each of the four corners of the room (and behind the screen.) Each speaker is a line with a tweet, 2 mids and 8 woofs. No sub needed. The walls are lightly padded to kill reflections and the whole ceiling is a bass trap. Each speaker is confined by the corner to a 90 degree radiation pattern at all frequencies so the power response is excellent. Different way to skin the same cat.

 

[ThomasW]

Anyone out there heard a DIY sealed sub paired with maggies?

A critically damped box "Q" of 0.5 works well with Maggies. I have Maggies and used such a box for quite sometime. That being said, IMO an IB or dipole sub is a better match.