[wadesi]

Hi Folks,
I've been reading like crazy over the last couple of weeks and a DIY sub project is definetly something I want to get into.
My Project:
I am building a new home and we have a home theater room/rec room with a projector and 110" screen along the front wall. Due to WAF issues I've had to install all 7 speakers in wall. I got a really good deal on some nice Klipsch speakers and I'm sure with a little tweaking I will be happy with them. Room dimensions are 19x22x10=Approx 4200cuft. For this project, I will be building a sub box which will go in the wall and be used for mostly movie/tv/sports watching. The best place to place this speakerbox is along one of the side walls towards the back of the room (opposite the screen, behind and to the side of the sitting area) I tried to place it along the front wall but there is no place to put it as 3 of the walls have a concrete foundation and the area is too shallow. This wall panel which I want to put it in is pefect in my opinion as it is framed out pretty far from the wall giving my plenty of space. Space available for the sub box is: W14"xD14"xH10'. The box needs to be 14" wide to fit inside the studs and can be 14" deep. Ceilings are 10' tall so height is not an issue.
I would like to use the Shiva-X 12" driver.

Option 1: One 12" Shiva-X driver in a sealed box sized at 14"x14"x36"=approx 4cuft
Option 2: Two 12" Siva-X driver in a sealed box sized at 14"x14"x60"=approx 6.8cuft

Why sealed box: I've been reading that this is best for my first build and easiest to build. I'd like to give this a go. I will make sure it is braced very well as it is a pretty big box. I'll also attach it to the studs well to limit vibration. I've made some car speaker boxes and know my way around a workshop. I'm comfortable making this box. One thing I have going for me is that since this is in wall it doesn't have to look good. It's all about function over form.

Questions:
1. What option above would be best in this 4000+ cuft room. Since this is going in the wall, I'd rather slightly over build than under build. I want good clean bass that will work well for sports and movies.
2. What affordable amplification would you suggest for this build? I'd like to use a stand alone amp which will sit with my home theater equipment. What are good powerfull amps that won't kill my pocket book? Ideal budget would be $300 for Option 1 and $600 for Option 2. (amplification)
3. Is there anything I'm missing in my planning above? Am I completely CooCoo for undergoing this project in my first go around?

All your comments and questions are welcome. There are some great folks on this forum and I hope to get some really good feedback. As I start work I'll be sure to post pics.
Cheers!

 

[wadesi]

Haha, sorry for already adding to my confusion but I would also like to propose a Option 3.
- 2 individual sub enclosures (used in option 1) placed side by side in two wall panels.

 

[applez]

First, you can use the edit feature.
Second, for your amplification purposes, either the EP1500 or EP2500 would suit you perfectly for your subs as you don't really have any use for a plate amp since its in the wall.
Third, I would personally do 2 subs just cause it looks symmetrical, but i'm sure making two holes in the wall isn't the best idea.

 

[wadesi]

Thanks Applez. Do you recommend 1 enclosure for both subs or two seperate smaller enclosures?

 

[Mike P.]

Space available for the sub box is: W14"xD14"xH10'.

That would provide about 10 cu.ft. for a box. Would it be possible to use all of the space?

Room dimensions are 19x22x10=Approx 4200cuft.....I'd rather slightly over build than under build. I want good clean bass that will work well for sports and movies.

Be aware that's a big room for a pair of 12 inch sealed subs to fill.

 

[wadesi]

That would provide about 10 cu.ft. for a box. Would it be possible to use all of the space?



Be aware that's a big room for a pair of 12 inch sealed subs to fill.

I can easily go up to about 9.5 ft.

Do you think 2 x 12"s is not enough? What do you suggest?

 

[Mike P.]

Since your box width is limited to 14 inches you have to use 12 inch subs. Porting the Shiva's would give you much more low end output.

 

[wadesi]

Would a Infinite Baffle design work well for this application?

 

[fredk]

Would opening up the wall space between studs to the attic (if that could be done) be enough of an opening to turn this into an IB?

 

[Mike P.]

Would a Infinite Baffle design work well for this application?

It would work but it will take more then 2 12 inch subs to get decent SPL.

 

[Ricci]

Right. That's a big room and 2 sealed 12's will be pushed hard to fill that up. I propose this... Either somehow port the 2 Shiva's like Mike suggested, or alternatively use $300 for the EP2500 and the other possible $300 from the amplification budget for option #2 and get 2 more Shiva's and run 4 of them sealed off of the bridged EP2500. If you can somehow do an IB you could get cheaper 12" IB drivers Like FI IB3's and even run more of them. The 2 ported Shiva's will be the most budget friendly option.

 

[wadesi]

Ok, another question which may help make my decision for me. I am currently thinking of placing these subs behind and to the side of the sitting area. Is this a bad place to put the subs? Another option is to place the boxes in the ceiling between the screen and front speakers and the sitting area. Will it sound odd to have sound coming down from the ceiling?

There is plenty of room in the ceiling to place these boxes. Box size would be approx the same and a IB design would be possible. The only problem I see is that this is a basement and there is a bedroom above this room. IB setup would create quite a bit of vibration in that room. The benefit to this setup though is that these will be place in front of the seating position instead of the rear. They will be placed approx 6ft from the front wall with the screen which is about 1/2 way to the seating area. Everything I've been reading is saying you want the subs in front of you.

Is there any cross contamination of sound waves by having the subs firing down over the same area as the fronts are firing out?

Sorry if any of these are noobish questions but I'm tyring to learn as much as possible in a very limited amount of time.

 

[RICKPTAK]

I built my Shiva-X sub into the wall similiar to what you are trying to do. My box was approx. 8 cu/ft ported with a 6" precision port tuned to 15Hz. To fit the port in the shallow depth I used a 6" PVC elbow. My room is about half the volume of your room and I am running it with a 380 watt plate amp and have more than enough bass. If you build two for your room with about 500 watts each you should have more than enough bass. My main speakers are Axiom in walls along with the sub makes for a clean room with no huge boxes in the room. Let me know if you need any more details on my set-up.

 

[Mike P.]

Box size would be approx the same and a IB design would be possible.

Ideally the volume of an IB is 10 times the Vas of the sub. For the Shiva-X that would be 60 cu.ft. per sub. Even at 4 times the Vas that's 24 cu.ft. each. As for sub placement, it's all about how the sub interacts with the shape and size of the room. if you have a sub or can borrow one, try different locations to see how it sounds at the seating area. Better to experiment with placement now then to build subs into a wall and find it doesn't perform as expected.