Need advice on subwoofer drivers for DIY

[tigerwoodKhorns]

I am piecing together a home theater system and need some subwoofer driver advice. The entire all of the speakers will be in wall and I have a fairly large space below my fireflace where I can build in a couple of 12" subwoofers. I have a pair of Cerwin Vega 12" (LE-12S) subwoofers that I bought new in 1989, but they need refoamed and are designed to be in a ported box.

I have a few amps that I can use. One is a soundcraftmen amp that is something like 400 wpc at 4 ohms, and a QSC 2404 which is about 700 at 4 ohms.

My room is large (abut 20 x 50 - opens to my kitchen) but not a dedicated room, so I am not looking for max spl as I am restricted by the in wall speakers.

Finally, I am a 2 channel guy and not looking to go all out with this system. I have a JL F113 in my 2 channel sysem and love the tight bass of the sealed box. I remember building Rockford Fosgate Punch sealed boxes in the 1990's and liked the tiht bass that they put out.

So I have been looking at options. I want to build custom sealed boxes.

On the cheap side, I can use the soundscraftsmen amp and buy a pair of Infinity Reference 1260w 12-Inch 1200-watt high-performance Subwoofer (Single Voice Coil) $57 each. http://www.amazon.com/dp/B0028AVGEO

Or I could use the QSC and get a couple of JL 13w7 woofers. But they are 3 ohm and really pricy.

I read on the internet that the following are comparable to the JL and much cheaper:

adjacent audio avalanch SI MagIDMAX 12D2 V.3 FI audio Q Digital designs TREO Eclipse TI RE XXX

If the Infiity subs are going to be sloppy for movies, I would prefer to get a sub that will compare to the JL. The problem is that on the internet I do not know if getting a comparable sub for "half the price" means just SPL or actual sound quality.

Thanks.

[EdmundGTP]

I'd start looking at actual home audio subwoofers instead of car audio subwoofers. They are different animals, albeit in some cases only very slightly.

Have a look over at the DIY subwoofer forum sections over at http://www.hometheatershack.com/forums/diy-subwoofers/

Check out some of the builds over there. Figure out what performance specs you want to shoot for, then decide how much you want to spend. There should be plenty of ideas and info over there to get you headed in the right direction.

[tigerwoodKhorns]

Thanke for the advice. I'll take a look over there.

I didn't realize that there was a difference (except maybe for infinite baffle designs). The JL W7 driver is supposed to be the exact same driver in the F113.

[EdmundGTP]

Most of them are different; not all.

Biggest thing you need to evaluate before moving forward is your budget and what you want the system to do. Matching the performance capability of the F113 system isn't going to be "cheap" either way, and will be damn near impossible using a pair of $60 woofers and only 700 watts.

Figure out what you want the system to be capable of. I.e. XXX dB @ XX Hz, with a -3 dB point of XX Hz

Once you decide that, it may be more cost effective to use 1 15 inch or 1 18 inch sub instead of dual 12's, or maybe even a single driver with a passive radiator. There are many options, but once you narrow it down to a few choices for drivers, amps, enclosure types, you can use a program called WinISD to fairly accurately assess what the true performance capabilities of the sub will be.

A couple years back I was debating doing a custom build sub and was much more knowledgeable on components that were available back then. Not so much these days. As luck would have it, I came across a smokin deal on a large eD sub that fit my goals and just couldnt pass up.

The bang/buck ratio on a DIY build can be HUGE, and the guys over at HTS can help out with that.

[CECAA850]

Find the max dB output of your mains, add 6 dB or so and have that be your performance goal.

[Thaddeus Smith]

i've had great success with this one: http://www.parts-express.com/pe/showdetl.cfm?Partnumber=295-468

[EdmundGTP]

Find the max dB output of your mains, add 6 dB or so and have that be your performance goal.

Good suggestion!

[tigerwoodKhorns]

I looked up the subwoofer that I had before the F113. It was a Klipsch SW15 from the early 90's. It only did 110 db and had plenty of bass quantity for me, even in this room. It was just slow and sloppy.

THat speakers thta I am going to use can only handle 75 watts and are 93 db so this shoudl work because I will not drive it that hard. So what I am looking for is a sub that can do maybe 110 to 113 db that is tight and will work well for movies. I am thinking 2 12's.

Is sealed the way to go. I know that sealed is usually tighter.

[CECAA850]

With those mains, start with one 12. It may be all you need. You can always build a second one if necessary.

There's always a billfitzmaurice design. Yo could build a Table Tuba using one $40.00 8" driver and have more than you'll need. Of course you'll spend $100.00 or so on a plate amp also.

[tigerwoodKhorns]

Funny, I was on Volvotrenter's website last night looking at the tapped horns. The thread that started it is 300 pages long, so I will not be reading it. But it looks interesting.

I want this system to be completely built into the architectural features of the room. I have two spaces where I can build 4' x 2' x ~13" high. This will leave me room across the front for about 7 lf of albums that can be completely hidden.

The tapped horns look interesting, but I do not like the driver being in the horn path (I know, it is not a concern).

Where can I find plans or a forum where I can design these boxes. I have a Soundcraftsmen amp that is about 400 wpc at 4 ohms that I can use. Looks like I will be restricted to 10" or 12" drivers. I think two reconfigured table tubas with smaller drivers will be perfect. I like the sealed box.

[CECAA850]

TH's (tapped horns) and FLH's (front loaded horns) are two different animals. I was referring to a front loaded horn whos driver is in a chamber seperate from the horn itself. Plans can be had for $15.00 HERE . If the specs on your mains are correct, you really won't need 2 unless you're trying to fix some room issues. The horns are very efficient. For example, the horn sub I'm using with my Lascalas is a 19" cube and has an 8" driver. I'm running 25wpc to my Lascalas and about 100-125 wats to the sub and the combination will get LOUD in the room that it's in (roughly 20' x 21').

[CECAA850]

You can see my sub being built HERE. The thread was started by forum member psg, but my build was posted there as well as his. There's a lot of good build info there as well.

[tigerwoodKhorns]

Carl,

I read just about the whole thread. Nice job on your build. Beautiful cabinet. You definately have a lot of experience with subs.

I like the tuba, but do not have room. I have 2 spaces under my fireplace and TV where I can fit a 4.5' x 2' x 13" high box (so I can fit 2 of these).

I am thinking two boxes with 10" drivers. Where can I find plans or equations to make plans for this? For some reason I like the idea of a sealed box going into a horn (like the tuba).

Any advice? Can the tuba be modified?

Should I look at tapped horns?

Thanks.

[CECAA850]

Designing a tapped horn ot front loaded horn is not something you'd want to try for your first project. You'll need to find a proven design that would fit into that space. You do not want to take a plan and change it, that would be disasterous. I'll look around and see if I can find something that would fit. The easiest alternative would be 2 sealed subs. They are the easiest to build and design. Next would be 2 ported subs. A little harder to design, but not too bad. Horns will give you the most output but it may be hard to find something that will fit in the allotted space. Let me check a couple sites for you.

[CECAA850]

That space is HARD to find a box for. THIS horn should fit, but in that space, you may not find a horn that goes low enough for HT. You should be able to get lower with a ported sub but it won't be quite as loud as the horn but with your mains, it shouldn't be an issue.

[CECAA850]

So that you have realistic expectations:

There are 3 things that are desireable in a sub. High sensitivity, small size and depth. You can only have two out of the 3. If you've allready picked small (by your predetermined available space) you need to determine if you want loud or low. There's no free lunch, you only get 2.

[Thaddeus Smith]

So that you have realistic expectations:

There are 3 things that are desireable in a sub. High sensitivity, small size and depth. You can only have two out of the 3. If you've allready picked small (by your predetermined available space) you need to determine if you want loud or low. There's no free lunch, you only get 2.

pretty sure i have all 3

[tigerwoodKhorns]

So that you have realistic expectations:

There are 3 things that are desireable in a sub. High sensitivity, small size and depth. You can only have two out of the 3. If you've allready picked small (by your predetermined available space) you need to determine if you want loud or low. There's no free lunch, you only get 2.

I know the rule, I thought that my space was large.

So, you know that I had to figure out a way to make this work. Damm OCD. I found a "compromise" solution. The bad part, I can only fit one subwoofer in the spot (with a little redesign of my space). The good news, I can fit a THT low profile.

The website lists a 15" x 18" x 72" enclosure which will work. It will be corner loaded because of the layout (it will fire into a corner at 90 degrees). Because I found a way to combine the space, the 72" length leaves me an extra 48", so I can work out the corner loading and leave enough room to access the woofer.

I can also build it where I can remove the entire subwoofer enclosure if ever necessary.

I really appreciate your help and taking the time to look some things up.

[CECAA850]

So that you have realistic expectations:

There are 3 things that are desireable in a sub. High sensitivity, small size and depth. You can only have two out of the 3. If you've allready picked small (by your predetermined available space) you need to determine if you want loud or low. There's no free lunch, you only get 2.

pretty sure i have all 3

Define "small size" for me.

[CECAA850]

So that you have realistic expectations:

There are 3 things that are desireable in a sub. High sensitivity, small size and depth. You can only have two out of the 3. If you've allready picked small (by your predetermined available space) you need to determine if you want loud or low. There's no free lunch, you only get 2.

I know the rule, I thought that my space was large.

So, you know that I had to figure out a way to make this work. Damm OCD. I found a "compromise" solution. The bad part, I can only fit one subwoofer in the spot (with a little redesign of my space). The good news, I can fit a THT low profile.

The website lists a 15" x 18" x 72" enclosure which will work. It will be corner loaded because of the layout (it will fire into a corner at 90 degrees). Because I found a way to combine the space, the 72" length leaves me an extra 48", so I can work out the corner loading and leave enough room to access the woofer.

I can also build it where I can remove the entire subwoofer enclosure if ever necessary.

I really appreciate your help and taking the time to look some things up.

Glad to help.

You realize that you'll be building a sub that has WAY WAY more output than your mains, correct? The only reason I could imagine building that sub in your scenario is if you're eventually going to go to larger mains and you want to "future proof" your system.