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Discussion Starter #1 (Edited)
I have been lurking on this site for quite some time and now I am finally getting serious about setting up a home theater in my house.. I have a 12' x 17' room with 8' ceilings. The front right corner of the room opens up into a short hallway and stairs. My first thought "B" was to buy a BIC F12 for $200, put it in the front left corner and be done. Then I read ,and saw, some amazing Horn woofers and thought about using an area beside the couch to tuck a "hidden" sub away in the back left of the room "A" . I have an area of (roughly) 12" x 26" x 60" to play with. The box would be sandwiched between the couch and wall. Is this enough room to get a good sounding $300 DIY horn vs. a purchased unit? As far as complex design and construction, I have all the tools I need, access to powerful 3D design software a large plotter/printer and lots of woodworking experience. This will be used almost exclusively as a HT system. Before anyone asks, the TV is centered above a fireplace, so it cannot be repositioned. Thanks!

Edit: I'm not stuck on horns, more intrigued than anything, but strongly considering a large low tuned ported enclosure as well.
 

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Not sure "horn subwoofer" and "hidden" can be used in the same sentence, unless you also include the word "not". ;)

Where are you pointing the mouth of the horn? If it's up in the air I would suggest you reconsider. That alignment favors being aimed into the environment at, or least least in the general direction of, the listeners. They can be a bit sensitive to placement.
 

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Discussion Starter #3 (Edited)
The mouth would have to point towards the TV. The only other option would be to make a sub in the "B" area on the picture, but I don't want anything larger than about 5cu. ft. to be in the front corner . I could also place a sub in the bottom right of the picture but I'm not sure how it would sound. I'm not really sure that space is available though. We are in the middle of a large remodel and have not decided what to do with that area.
 

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Given the circumstances, I wonder if it wouldn't be better to hold off on the project until the remodel is complete. That might help make some of these decisions easier.
 

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You could possibly build a sonosub. 12" driver in a 16" tube. Jim could be right though, if the room is upside down right now, you might be better to wait.



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Discussion Starter #6
Well after reassessing the room, I don't think it is safe to put a sub anywhere other than the A and B options I have listed above. The deal with the long, narrow area is that I would like to keep the couch about a foot away from the wall and make a long table there to set drinks on while watching movies and I love the idea of utilizing that 12 cu.ft. of free space. I am now thinking that either the 12" x 26" x 60" space could fit a side-firing sub with a port in the top, but I have never heard a configuration like this so I have no idea how the acoustics would work out. If not that, then a sonotube or LLT (I think I can squeeze 6.5 cu.ft. in the front right corner).
 

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I am now thinking that either the 12" x 26" x 60" space could fit a side-firing sub with a port in the top, but I have never heard a configuration like this so I have no idea how the acoustics would work out. If not that, then a sonotube or LLT (I think I can squeeze 6.5 cu.ft. in the front right corner).
Brian Ding, the man behind Rythmik subwoofers, was recently considering something quite similar; a sub with the port firing out the top. He determined that the orientation would not work from an audio perspective, and that's disregarding the aesthetic concerns even. There's probably a good reason no one else has done it before, and that's most likely because it wouldn't work properly or look good (just think of how many kids toys would end up at the bottom of the enclosure, not to mention a pile of dust as the years accumulate)

A sonosub has many advantages, so definitely something to consider. Most of them adhere to the LLT design, by virtue of their size, which also leads to a more efficient arrangement.
 

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Discussion Starter #8
Ok, thanks for the help. I am going to go with a standard LLT in the front left corner of the room built into a hidden cabinet/table. I like the sonotube idea, but they look more oabtrusive than I would like. Now comes the hardest part of the build...talking my wife into a 12 cu.ft. (or larger) "decorative piece". It will be quite a while before I start the build, but I want lots of time to research and design. I will post a build thread once the process starts. Thanks again for the pointers.
 

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Discussion Starter #12
I am thinking about a 15" down firing Dayton Classic 15" (DCS380) in a 12 cuft box tuned to 18Hz next to the couch. Winisd is showing max excursion at only about 100w when the sub is rated for 250w. Does this seem right? The specs show the max excursion at .33". On one hand, it is nice to be able to use the sub to its full potential with a smaller amp...but I feel like I should be using a larger amp since the sub is rated for it.
 

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If you're planning on using that "A" space for a table anyway, you could possibly kill two birds with one stone by either 1) building the box big enough to work as the table (and dampen/isolate the table surface somehow) or 2) build the box just small enough to completely fit inside the footprint of the table so it is "hidden".

Horns are awesome because of the high sensitivity... and they're a pain because of the high sensitivity. Have you taken a look at the THT and THTLP designs from Bill Fitzmaurice? He's got some stuff on his website that, while not the simplest of designs to execute, are very flexible in terms of driver selection and finished size. You said you had the equipment and the experience to pull off a complex design, so it might well be worth looking into.

As Jman said, horns can be very finicky about placement and direction. The difficult part of this dilemma is that what you really want to do is test it in the room... which you can't do without building a horn.

Another option in a different direction is to go LLT (Large Low-Tune) vented. These boxes have the advantage of providing very deep extension (into the teens in Hz) while maintaining reasonable linearity. The disadvantage is that they're typically power-hungry because they need fairly robust drivers to deal with the rigors of operating in those ranges within the parameters of a vented orientation. Horns can perform similarly with less power.
 

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Discussion Starter #14
I am planning on a Dayton classic 15" with a Bosch 300w amp in a 12cuft box tuned to 18Hz with the driver and port down-facing. I will put a marble top on it with gel vibration pads under it. I am going to go with the classic 15" for now and if I blow it up I will step up to the Ultimax driver.
 

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Why not just do the UM driver to start with?


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Proof of Concept. Build it cheap first... and if it works well, replace the cheap parts with better ones later. Same approach I'm currently using for my IB setup. I've got 4 GRS 12" subs that cost me a total of $80. The specs lined up nicely with what I needed. I'll switch the the UM 12" eventually when don't mind dropping $600 on new drivers, because those are much better in terms of frequency response and air displacement and they still fit my specs.

to OP: Make sure those two drivers will perform similarly in that orientation. Granted, LLT setups offer a little more leeway than something like a minimum-volume acoustic suspension box... but you don't want any nasty surprises.
 

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I am planning on a Dayton classic 15" with a Bosch 300w amp in a 12cuft box tuned to 18Hz with the driver and port down-facing. I will put a marble top on it with gel vibration pads under it. I am going to go with the classic 15" for now and if I blow it up I will step up to the Ultimax driver.

If you REALLY want to dampen vibration from the box into the marble top (which will probably look very nice, btw), go with magnetic levitation. A few strategically placed rare-earth magnets and some padded corner bumpers will give you the coolest floating stone table top ever!
 

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Proof of Concept. Build it cheap first... and if it works well, replace the cheap parts with better ones later. Same approach I'm currently using for my IB setup. I've got 4 GRS 12" subs that cost me a total of $80. The specs lined up nicely with what I needed. I'll switch the the UM 12" eventually when don't mind dropping $600 on new drivers, because those are much better in terms of frequency response and air displacement and they still fit my specs.

That's perfectly reasonable. I was just thinking measure twice, cut once.


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As long as the parameters of the drives in question are pretty similar, he should just be able to drop the new one in place and be good to go.

OP, it might be worth your while to make a removable baffle plate when you prototype. Then you can make a new baffle for the new driver and not have to worry about silly details like mounting holes lining up, or having too much (or too little) play in the cut-out. Once you're satisfied it will work, and you're ready to swap (or you set the Classic on fire, or whatever) you just pull out the whole baffle and drop the new one in place with the driver already mounted. It will take a lot of the headache out of the upgrade.

AND, if you have a levitating top, you won't have to deal with the extra weight when you try to flip it over. :)
 

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As long as the parameters of the drives in question are pretty similar, he should just be able to drop the new one in place and be good to go.
That's what I mean. If the parameters line up, and the modeling is the same, why waste the money on the junk driver in the first place.



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