Duel sealed 15s Vs Tuba HT?

The THT (horn sub) will most certainly have more SPL but the duel 15's in a sealed cabinet will likely go down lower. You might look into LiLmikes F-20 as it is also a horn sub and is just as good as the THT.

So you have about 1200 cu ft. That's a small room and 2 sealed high travel 15's would cover it fairly well . But... you could save a bunch of cash by doing the THT and have plenty of SPL there too. The sealed boxes will play a little lower and allow more flexibility in placement, but you could always build more horns later. It really depends on what build you think would be more fun.

build the f-20 over the tht for many reasons, but most obvious, the build requirements. you could build 4 f-20s by the time you build 1 tht.

There's no such thing as a free lunch, and in the case of tapped horns it's excursion and distortion. The THT has lower excursion than the F20 for the same input, so its displacement limited output is higher, and its distortion is lower. Not that it matters at sensible levels, but staying at sensible levels isn't always the intent when one builds either of these.

"There's no such thing as a free lunch, and in the case of tapped horns it's excursion and distortion. The THT has lower excursion than the F20 for the same input, so its displacement limited output is higher, and its distortion is lower. Not that it matters at sensible levels, but staying at sensible levels isn't always the intent when one builds either of these."

those are front loaded horns, not tapped horns.

My mistake, I saw a pic of a large tapped horn in the F20 thread and thought that was it. In any event an excursion chart I came across in the F20 thread shows higher excursion than the THT, reinforcing my mistaken assumption. Just having looked at a build pic of the F20 the parts count is similar to the THTLP save for the lack of bracing, which IMO isn't optional equipment.

minor miss. the excursion of the f20 is a little higher because it is tuned a little lower. tradeoffs. ;-)

I built the "low profile" version of the THT. It was fun to build and I am very pleased with how it turned out. Here's my build thread, though it isn't entirely relevant to your THT plans: http://www.avsforum.com/t/1327401/ready-to-diy-starting-with-a-tht-low-profile-sub

For your room with the 4 ft walls and slanted ceiling, making some big horn subs seems like a good idea. You can place them near the 4 ft walls without really losing usable floor space (since the ceiling is too low to stand there anyway). The THT and F20 are both under 4ft tall.

Go for it!

-Max

may not be free lunch, but there is free plans. f20 has great documentation and plans for free, THT plans=$$$.

You could also make the lp version of the tht and lay in on its side. Make it into a bench or table. Get creative.

Here's what I did with mine

Shttp://www.avsforum.com/t/1438536/dual-thtlp-architectural-series#post_22584862

Just one would load up that room big time and they have great sound quality. Two in that space would be kinda nuts. That would be the advantage of the smaller subs. Easier placement.

1. I use one of these for each sub. http://www.parts-express.com/pe/showdetl.cfm?partnumber=300-813

Use this driver. Not the HO. http://www.parts-express.com/pe/showdetl.cfm?partnumber=295-190

2. Don't use tight bond. Use Loctite PL Premium 3x.

3. Horn subs sound great. Tight sound. No bloat. No port noise.

If $14.95 breaks your budget you've chosen the wrong hobby.

These are the recommended drivers. They also work in the F-20. I don't believe the HO works.

http://www.parts-express.com/pe/showdetl.cfm?partnumber=295-468

http://www.parts-express.com/pe/showdetl.cfm?partnumber=295-190

Concerning screws, read the plans when you get them. You definitely want to use PL Premium glue. And you don't necessarily need screws, but they can be helpful to hold panels in place and pull them together while the glue is drying. A brad nailer can be useful for this, too. However, for every brad or screw that you use, remember that they don't hold the sub together (the glue does that), and you will probably need to fill the hole and sand it before you put the final finish on (unless you're using carpet). Having just spent 2 hours sanding the Bondo off two AutoTuba subs, I think I will seek to use as few brads as possible next time.

-Max

Concerning amps, I just picked the Crown XLS 1500 and will be using one channel of it to power my THTLP most of the time. I wrote up my evaluation of a few different options, and why I picked the Crown in this post: http://www.avsforum.com/t/1432336/build-log-a-pair-of-autotubas/30#post_22592850

They are a bit more but they have no fans. I can adjust phase and gain separately. And they look cool. And I guess if one craps out I still have another going.

The HO isn't one of the recommended drivers for the tht. It takes very specific drivers. Everything is in the plans.

FOLLOW THE PLANS and you can't go wrong. Two tips though.

1. Wax paper between the material and your clamping equipment. Glue won't stick to it.

2. Epoxy the nuts in for the driver. I used pl on mine and didn't have a problem but epoxy has saved my butt and a recent build I did.

There's a reason folks publish plans for horns, but not for simple sealed boxes... the latter are a lot easier to build, and most folks can see that's needed. I'm not familiar with Bill's work, but I would take brian6751's advice seriously if you choose to go ahead with the build. You may be able to find a lumber store that will cut things down for you, but 6 square panels will be cheaper than the odd cuts of a horn design. I've built horns, and they do work very well, but I would never suggest someone your age start there, unless you had lots of woodworking experience or a supervised shop.

Stepping back, the only trick to building rectangular boxes is accounting for material thickness. It's easy to calculate interior volume by subtracting 2x material thickness from outside dimensions. A simple box results from:
- 2 panels outside dimensions
- 2 panels inside dimensions
- 2 panels ID in one direction, OD in the other.

The first and third pairs form a cylinider, the second pair are plugs in the ends. And if you can get straight, square cuts, any good wood glue and clamps are all you need to assemble. Then there's the holes....

HAve fun,
Frank

>> Titebond PL Premium etc. Is there a huge difference?

Yes, PL Premium expands as it hardens, so it will fill any little gaps that you may have. And its very strong. Both very important especially if you don't want to use nails / screws.

>>2. What is Epoxy? Nuts in the driver? I haven't read through the guide but that is one thing I dont know how to do is mount the driver

Epoxy is a two part glue, adheres well to metal and glue - used to glue T nuts or hurricane nuts into the panel that the driver is mounted on - the driver then is bolted to those glued in nuts.

>> So reading through these instructions... Yeah... I am lost... I really didn't think it would be this difficult. I can't even follow along with the instructions... I don't really want to post too much on this thread. In case I break some copyright law

Bill has his own forum, might be better to ask the BFM build specific questions there, there are authorized (pro) builders that make them all the time and would be able to answer any question you might come up with.

>>What amp do you guys recommend for two THT subs using the Dayton Audio RSS390HO-4 15'' driver in each one? I don't really want to use a plate amp... Id rather it be in the rack.

I used a QSC RMX850 that I had used before for a rack guitar/synth setup. Behringer, QSC, Crown, etc. all make suitable rackable power amps, check eBay or craigslist.

>>I have seen some people glue everything together and some people glue and screw everything together? I was planning on using TiteBondII as the glue. I am unsure about what screws to use... Advice?

I used drywall screws - its actually not that important what kind of screws, they are just there to keep things tight while the glue dries.

If you can follow directions you can build them. The most important directions were those contained in the cover email that accompanied your plans.

There is no disagreement on which glue to use to build a THT: use PL Premium.

Read my THTLP build thread that I linked above. It has lots of pictures and details, some of which are applicable to the THT. There are some recent THT build threads, too. That will give you some tips and additional details. It may seem overwhelming at first, but it makes sense one you get into the build. Take it one step at a time and you'll be able to do it. Ask questions if you get stuck.

-Max

I bought the THT plans from Bill but in the end decided to build the F20 because it fit my room better. Either would be an excellent choice. I think the F20 is a little easier to cut and assemble but if you follow the plans one step at a time the THT would go together the same way. The sound you'll get will blow you away. They're really that good.

I used pocket screws on mine on the side that faces the room and screwed from the outside on the side that faces the wall. It was a reverse from the plans but doesn't affect anything sound wise. The pocket screws are great for projects like this. You slap down the glue (read PL Premium!) and screw it together and it is rock solid and set immediately. Just pre-assemble it before you glue and all of the pilot holes will already be there. You could always clamp the last side and glue for a complete screw-free look if you want. Then slap some paint on and pour the juice to it and you're done. I built mine in a weekend and then painted it and moved it in. No matter which sub you choose you're going to be happy with it.