[dougme57]

I am getting ready to add a couple of more subs to my home theater. I have a big room, 52'L x 17'W with 9' ceilings. it is all open but my theater part is about 12' of the 52 with a pool table in the middle and another seating area on the opposite end.

I have ACI Sapphire III LE's on diy stands and I currently use a Parts Express sub 120. I want/need more bass for movies and want articulate bass for music. I have a budget of $1000. I have been looking at the following 12" sealed subs:

1. Diy kits from Parts Express
2. SVS 12"
3. Outlaw LFM

I also looked at the downfiring plans at Rythmik and wanted opinions on how they might work with the Dayton drivers and plate amps. My basement is carpet on concrete floor so I am ok with a downfiring sub. I like these plans as they are 24" tall and I was considering using them under my monitors like the Jaquars, Watt/Puppy, VR4 etc. I appreciate any ideas.

[Bob in St. Louis]

With a room that size, I wouldn't think some 12" subs would do much.
Do you have the ability/space/room for an IB?

[JohnR]

Hi, it sounds like you're considering DIY? FWIW the dayton 15" drivers aren't much more than the 12's - http://www.parts-express.com/pe/showdetl.cfm?partnumber=295-468

The other thing I'd suggest is not putting them under the monitors. You can try this with your existing sub: move it along the side wall and measure the response in the seating area as you do. 12.5' might be an interesting location.

[Teyry]

SVS makes a good subwoofer for the price. I have owned a PB13Ultra for 4 years now and it has been a very capable and reliable sub.  With a $1,000 budget I might suggest you stretch it a little if you can and go for the SVS PC12-PLUS. I don't think you could get much better for $1,200. You have a pretty large room so you could always pick up 1 sub now and budget for a 2nd in the future if you felt you needed it. I believe SVS also pays for return shipping if you are not satisfied.

I had also owned a $3,000 REL Stadium III sub in the early 90's and a pair of Vandersteen 2wq's after the REL. I absolutely loved the Vandersteen's for music & movies. I had sold my Vandy's in the mid 90's and still miss them, especially on music. The SVS will remain as my LFE sub for movies.

[Dan Driscoll]

With a room that size, I wouldn't think some 12" subs would do much.
Do you have the ability/space/room for an IB?

I agree with Bob, given your description, an IB (infinite Baffle) would be ideal an ideal solution for your room.

[dougme57]

I have to look at an infinite baffle set up, have not considered it and am not familiar with them at this point. Thanks for the suggestions.

[Bob in St. Louis]

Here's info on what they are: http://ibsubwoofers.com/

Enjoy the ride. 

[mcgsxr]

Is placement an issue for IB's?  Do they have to be in the front of the room to integrate well etc?

Down the road, there is space under my stairs that I could use for an IB sub to augment my HT sub burined in the wall in the basement.  But, it would be at the back corner of the room, total opposite to the surround setup etc.

[Bob in St. Louis]

I don't think it's any more or less of an issue than a regular sub. (afaik) But if I had to make a guess, I'd say it's less important.
You can still optimize its placement by using the old trick of placing a sub in your listening chair (turning it up loud) and walking around the room and finding the loudest area.
That's where you should place the IB. But IB placement generally is subject to a convenient place to poke the hole in the wall/floor/ceiling.
But the bottom line, is that with an IB worrying about placement is like worrying about placement of a large nuclear device. It really doesn't matter. 

Bob

[dougme57]

Bob, I do have a small closet that is under the stairs, never use it and it had not come to mind. It is really odd shapes but after a lot of measuring I calculate it is around 300 cubic feet. If I used 4 15" drivers the total vas would be about 6 times, not the reccomended 10. Also what kind of power would i need fir this?

[Bob in St. Louis]

Six is fine. Mine is 4, and all but the most hardcore IB fanatics say that 4 is absolute bottom of the line minimum. Anybody that says my bass "isn't built correctly" has an open invite to my house to show them what "not built right" feels like. 

Regarding power, you can buy a couple thousand watts for about $500. Remember, this ain't no tube amp we're talking about. This is sheer "rock your socks" horsepower, it doesn't have to be pretty.
Think of names like "Crown", "Pyle", "Behringer" for a few examples of cheap watts. You're only doing the bottom octave or two, so sound quality isn't an issue. Parts-Express sells cheap watts. Some of these "pro" amps have loud fans, but that can be fixed by purchasing a specially designed super quiet fan for about $20.

The only word of caution I have with using a closet, or any other space that is accessed by a hinged door, is you have to remember that slamming the door will cause over excursion and damage the drivers. Lesson is....don't let the kids play in that room. Maybe put the lock on the outside of the door.

Bob

[dougme57]

Thanks Bob! I have acouple of more questions as I have been looking at everything I can find. First the area under my stairs is an actual loset with a regular door.

I have one place I can install between studs due to plumbing in the walls. I have about 24" of height to work with due to wainscotting on the wall in my basement. It would be placed just off the floor and covered with a air return grill. Would I be better off to use 2 18" or 4 15's. It would be simpler with the 2 18's.

I was looking at amps and my question is do I need the equalizer and if so have you seen the new Behringer INUKe's with dsp? Will this replace the equalizer? The 1000 model has 330 wats per channel @4 ohms.  Is this enough power? The 3000 jumps to 880.

Thanks for all your help.

[Bob in St. Louis]

Not sure two 18's will be "enough" in a room that large. Keep in mind, that room is massive. Now....that being said, it's going to depend on how much of a bass freak you are. If you're a full blown home theater, electronica/dance/dubstep music type bass-head, then that won't be enough. But if you want a nice tactful addition to the lower octaves, then you'll be fine.

For EQ, all these need to see is content below about 50Hz. The rest of your system should take care of everything above that. So yea, you'll need some EQ, of some sort.

For watts, >>The Behringer NU1000 iNuke<< is a great looking unit. I know nothing of the DSP/EQ functions of it, but the watts are more than fine. If you use two 15" drivers, you can feed the a mono bridged mode of 1000watts. You don't want to use the dual channel capabilities at all.
It looks like there's a switch on the back to only allow content from 100Hz and below. Kind of a strange point to set things at, as far as I'm concerned. Maybe I don't understand the function though, as I'm basing my comment on the photograph of the back panel in the link I provided above.

Bob

[dougme57]

So if I build a manifold wiith 4 15" drivers would the 1000 be enough? And is my receiver's lfe enough equalization? do you just connect the sub out to the Behringer and speaker wire to the sub?

[dougme57]

And would 4 of these be better, Dayton Audio DCS450-4 18" Classic Subwoofer 4 Ohm? Or 4 of the IB 15"? I will be using Dayton either way.

[richidoo]

I think a pair of Rythmik 12" sealed subs with GR drivers would support the Sapphires adequately, probably play cleaner and louder than them, so you don't need more bass than you can use and the mains are only 7" drivers, so 100dB is the limit for them. You probably sit close to the speakers anyway, so no need to pressurize the whole room unless you have big dance parties, you know the ladies love some big bass...   Rythmiks can play high enough and fast enough to blend well with the Sapphire with reflex ports sealed, and small enough to place them close to the Sapphires for best stereo imaging in the upper freqs near the crossover. The servo amp makes the inexpensive driver and amp behave like a very expensive driver with a very expensive amp. Without the servo there's no way you can make Dayton budget drivers and plate amps sound as good. A pair of custom install rythmiks, plus a couple sheets of ply and some glue and paint will cost about $1300-1400, but I think you'd be very happy with those. Or buy them built for 1800/pair.

[Bob in St. Louis]

So if I build a manifold wiith 4 15" drivers would the 1000 be enough? And is my receiver's lfe enough equalization? do you just connect the sub out to the Behringer and speaker wire to the sub?

"Yes" (that's a bit of a generic answer since the driver choice hasn't been made, but 1000 should be fine)
"Yes"
"Yes"
....and.... "Yes"

Although Rich may have a point with how much of the room needs "pressurized". But what I don't know, is whether or not you can have "local pressurization".
Meaning that if you're using 1/3 of the room for the seating/viewing area, can you have enough subs to make it feel/sound right without your wave bleeding off to the back 2/3 of the room.

And "Yes", four 18's are better than four 15's. 

But again, we haven't established how much of a bass freak your are either. 

[dougme57]

Rich's idea is close to my original article thoughts, however I am very intrigued by using he ib. I am not sure how much a bass head I am.My teenage boys and I love explosions. Their x box rattles. The walls now but too boomy. I listen to classic rock, more progressive and fusion jazz.
I never hear the bass lines like I do with my phones.I was comparing the Graceland disc last night to my phones and while I have the detail and warmth I do not have that clean fast bass.

At this point I am leaning towards the ib with 4 18 Dayton and other he Berhinger. There is an used 1124 on Craig's list for 70, should I get that and the basic inuke 1000? I am getting excited about the project. Excuse my typing,  in the back seat with my son driving lol.

[dougme57]

Bob I just read your answer again, so I don't. I am liking the budget better on this project.

[Bob in St. Louis]

Ahhh...that's the reason. I wondered what the deal was with the typing. 

Based on your music selection, and IB is way overkill. But if you like movies that blow up a lot of stuff, an IB is unbeatable.
Not sure the specs of the 1124, but for $70, it's hard to go wrong. Give it a shot.

I like the idea of quad 18's though. You can blow up a lot of stuff with that.

Bob

EDIT: Which budget is better?