Help with sub design choices

[Micah Wells]

First off, great forum. I've been researching for a while and it seems that I have too many options and can't decide which way I want to go. It feels like everytime that I get settled on something, I read something that sounds better. So here's where I am:

My listening is 90/10% HT/ music.

My budget is $350, but could be ioncreased if needed, just would take longer.

I currently have the Dayton Tiny Mighty that I purchased to get me by until I could complete this project.

The enclosure will have to fit in an opening in the entertainment center that is 17" h x 24" w x 30"d.

Here are my questions:

Will I be limited to a sealed design? Or will a small PR design work? I was ready to build a few months ago and bought a pair of 12" PR's from Stryke, but didn't get in my order for the AV12 quick enough. So if I can use the PR's that would be even better.

I can't decide on a driver. Like I said, I was settled on the AV12, but since Stryke ran into trouble I have been looking at other options. Shiva? DPL12? Titanic?

While researching amps, I came across the Rythmik site. Now I am wondering about the direct sevo 12 they offer? It seems to offer waht I am looking for, good extension in a small enclosure, but I haven't seen much talk about it, the only thing I found here wasn't very complimetary.

While on amps, I have narrowed down to the ryhtmik 350 (standard if I go PR'ed, the one with the LT if I go sealed). Am I on the right track here?

I have modeled the different drivers and enclosures on WINisd, but since I have never done this before, it is very difficult for me to determine the difference. Do I really need -3 db to 20 Hz?

I want good HT rumble down low, something that can shake the house. I know that there have to be compromises, and that is why I am looking DIY, so that I can minimize the trade-offs. Any help or shared experiences are truly appreciated.


Micah

[BillFitzmaurice]

You might want to do one of my folded horns, but the sizes are a bit big. My Tuba 18 is 18x18x19 inches, my AutoTuba is 14x14 x32 inches. In either event they're designed to use boundary loading, thus their small sizes, and that means they won't go into an entertainment center. But I'd reconsider that idea anyway; subs and things that can vibrate, like stuff on shelves, don't get along well together. You can build either one for less than $100.

[johninCR]

Micah,

If you have a regular CRT television that sits directly above where you are talking about putting your sub, then your biggest concern is going to be magnetic shielding.

Can you use attic space above your room?

[RHosch]

If you were looking at AV12 designs, take a look at the TCSounds TC2+ driver, as it is close in design and performance to the AV12. They are available I believe from O-Audio and SoundSplinter (hope I got that last one right).

[wigginjs]

I say ported enclosure with the port facing the same direction as the driver (i'm guessing the cabinet is enclosed on all of the other sides). You could probably get away with a 12" driver, I think the Dayton 12" DVC or if it needs to be shielded the 12" DVC Shielded (this driver is not the same quality as the non-shielded version).

[Micah Wells]

Thank you for the replys. Sheilding should not be a problem, we have Sony rear projection LCD, and as I understand, unshielded speakers should not affect this TV.

Bill- I haven't even considered the folded horn design. I'll do a search and take a look at it.

John- I know where you are headed, the IB is not an option. The wife doesn't want to see abig sub in the room, and wouldn't even discuss cutting holes in the drywall. That is a shame because my attic is easily accessible.

RHosch- I have read that the TC2+ at O Audio is the old version that Stryke had problems with. However, the ones at Soundsplinter are the newer version. Can anyone confirm?

mOtion- The only problem I have found with ported is the length of port fitting in the small enclosure. If you have plans for an enclosure, please link them.

[johninCR]

Micah,

Since you have an attic, IB is the way to go. Just put 2 drivers, eg 2 tempests at $150/ea, in a manifold with a push/pull alignment attached to the rafters and cut a rectangular hole in the ceiling sheetrock. Cover the hole with a white grill and she won't even see it. If you plan it right, you could build it, then mount it while she's at the grocery store and have the finish work complete before she got back.

There's no way she'd have anything to complain about as long as you run the wiring down in the wall. No space is used, has great sound and extension with reduced distortion, greatly reduced mechanical vibration, and is stealthy and easy to build.

It really is the best option since you have an attic and space constraints in your room. Tell her just to trust you.

[Micah Wells]

It is interesting that you are proposing the IB set up. That is what brought me to this forum. I have already checked out the IB site, but I have a few questions. I need to be armed with as much ifo as possible. What size cutout would I need for the set up you suggested? What about amp? I live in Texas so the temps in the attic get very high in the summer. Would this affect the drivers or amps? Where can I get the grill to cover the openning? Running the wires in the walls might be a small problem, I prewired the house during its construction, so another set of wires could be dificult, but I think that I can make it work. As for doing it while she is out, not a very good idea. I would like to live in the house long enough to enjoy my work.

[johninCR]

If the attic gets hotter than a car on a sunny day, then you need more attic ventilation anyway, so heat shouldn't be an issue.

With 15" drivers you're talking about 16" by 8" or more, depending opon how you make your manifold and you could reduce the 16" mouth dimension some if necessary. A square hole based on your rafter spacing would work great and give you plenty of room and a bigger air flow area through the grill.

For a grill you could use something like a return air duct for an A/C painted white and use foam rubber to eliminate rattles. That would give you access to the drivers as well.

For wiring just use a 1" wood drill bit to make a hole in the top plate on that wall. Make a hole in the wall directly below that one. Put a weight on the wire and drop it down and fish it out of the other hole. Cover the hole in the wall with a cable TV wire plate, so don't make the hole bigger than that.

All pretty simple and easy. Much easier to make pleasing visually as well. Just do the attic work at night when it's cool.

[Hornlover]

Check out the 6th order subs at the High Efficiency Loudspeaker site. Go to downloads/enclosures. There are several using high efficiency drivers in ported boxes. The 6th order alignment gives you smaller size and lower response. Check out the article on alignments, and calculate box sizes for other drivers too. The Selenium WPU1505, at 3.59 cu. ft has an F3 of 28Hz, and the WPU1507, at a hair over 4 cu. ft with an F3 of 25 Hz are both high efficiency ddrivers, and will do great for both HT and music. They are both bargains, too, for that quality of driver. They will play loud with just a few watts. You can get pc boards for the 6th order alignments there, or use a plate amp that has a 6db boost available. For both of those drivers, a 100W plate amp would be more than enough.

www.highefficiencyloudspeakers.com