Help with sub design choices

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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
 
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.
 
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.
 
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.
 
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.
 
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.
 
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
 
I am going to pursue the IB solution. From what I have read, it will provide the type of output I am looking for. 16x8 doesn't seem like a big hole to me, we'll see if it flys. The concern I have with wiring is that we have fire blocks put in at about 4 feet. But since the entertainment center is tall, I can do a wall plate just above the fire block. I'll just have to play around and see what works. Needless to say, the wiring is not my hurdle. Don't get me wrong, my wife loves our surround sound, she is just not keen on the idea of permanent holes.
 
I'm making baby steps here. I had a serious talk with my wife last night. I got her to understand that I can put the "subwoofer" in the attic, out of site and get all of the performance that I will ever want. We already have two A/C vents on the front wall, and my initial thought is that the opening for the IB would be centered between those two vents. So I hope to find something that would look like the other two vents. She said that would work. Can I use the metal vent covers, or does that affect the sound? So, I have at least settled on a design. After looking more into the IB, I think that I have narrowed it down to a pair of Tempests or the Dayton IB drivers. I still have no idea about the amp. I plan on building the mainfold so that I can add two more drivers if I need to upgrade, so the amp will need to have the headroom to power all four.

Again, thanks for all of the info.
 
That Dayton is probably the way to go, since it is designed for IB use. Check out https://home.comcast.net/~infinitelybaffled/page2IB-Gallery.html for some examples of installs, grills, etc. to show your wife.

If you are going to make the manifold capable of 4 drivers, then square would be the way to go. 2 is likely to be all you need and you wouldn't want extra unused cavity depth as it may lead to an undesirable resonance.
 
So you suggest building the manifold with two drivers, then if I want to add more, rebuild the manifold later? If you think that the two drivers will be enough, then should I look at the PE 250 watt plate amp? My room is kind of big (16-22 w/ 10 ft ceilings) and has openings to the kitchen and Dining room. Again, I am using the Dayton Tiny Mighty now, so I might need to gradually move up.

Already showed her the pics in the gallery. She said, "that's not as bad as I thought." I just think that the A/C vent cover is an easier answer, but if it affects the sound, then I will build the grill cover out of speaker mesh.
 
johninCR

Some pro woofers will play that low. A simple dismissal of pro woofers shows a lack of experience with them. You just need to use the right pro woofers. When playing at typical listening levels, P-P excursion using a pair of the WPU1505s rarely exceeds .1 in. (less than 3mm p-p).
 
Micah,

I would build it to fit snugly between the rafters, because I'm lazy and that would be the easiest. Check the available grill sizes before deciding.

Note that most of those IB examples don't take advantage of the distortion reduction of push/pull alignment. Put one magnet in the manifold and 1 outside and wire out of phase. While the reduction in distortion may not be audible, distortion in the bass from subs lead to more room rattles. That's why an el cheapo sub can make things rattle in a room without true clean low end output.


Hornlover,

I agree with you 100% for music (with a few exceptions for recordings that have very low frequency content). For HT, however, I totally disagree. There is too much good stuff that the recording engineers put in the LFE channel for movies that is below 25hz. That ported setup simply won't move enough air for a prodigious bottom end. Even if it could, then it would be set so loud, that everything about 25hz would be way too loud. It's a woofer, not a subwoofer. Apply 50 watts at 18hz and see what happens.
 
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