Is an IB possible in my room?

**cburbs** · **07-02-09, 10:00 AM**

I am using the a300 from here http://www.rythmikaudio.com/amplifiers.html

**cburbs** · **07-02-09, 10:00 AM**

Do you think going this direction would give me a more thump in the chest since this is in the basement and cement floor?

**Mike P.** · **07-02-09, 10:14 AM**

By "thump in the chest" do you mean the tactile effect of low frequency explosions and such on DVD's?

**cburbs** · **07-02-09, 12:26 PM**

Yes -

**Mike P.** · **07-02-09, 01:18 PM**

I understand what you're asking, I started out with 2 12 inch Shiva sonotube subs in a cement basement Ht room that is 15' by 26'. They just didn't do it. Added 2 15" ported subs, still not enough. Retired the Shivas and added a pair of 18" ported subs, finally got it to where I wanted it. It takes serious woofage to feel anything tactile in a cement basement. I will admit however that I do like extreme levels which my 4 subs provide.
4 15 inch IB's will definitely improve the low end output for you compared to the 12 inch GR's that you have. But will it have enough tactile effect for you I honestly can't say. Depending on how fixed your budget is you may consider doing 18" IB's. 2 may be enough for you, if not you could add a another pair in the future.

**cburbs** · **07-02-09, 01:34 PM**

I think the other thing that may hurt is the 1 opening and the shape of the room. I don't in any way think my subs stink they just don't give me that low end thump I would like.

**cburbs** · **07-02-09, 01:39 PM**

Where does the Reckhorn B1 fit into the equation if I have a BFD already?

**Mike P.** · **07-02-09, 01:40 PM**

For the money you would invest in 4 15" IB's you could move the GR's and build a large ported sub with 2 18's that would fit between the speakers and could be used as a stand for the center channel. It's just an option, I can model it up to compare to the IB's if you're interested.

**cburbs** · **07-02-09, 01:43 PM**

Mike if you don't mind that if fine. I am just looking at options/alterantives right now so if it is too much time don't worry about it.

**Mike P.** · **07-02-09, 01:54 PM**

Not a problem. I'll need to know the maximum external box size that will fit between the speakers and we'll take it from there.

**cburbs** · **07-02-09, 02:22 PM**

OK I will measure that stuff up tonight.

**cburbs** · **07-02-09, 04:54 PM**

30" to bottom of screen.

28" between front speaker and center channel stand.

26" away from front of wall.

Otherwise like 90" between front speakers if you remove the center channel stand.

**Mike P.** · **07-02-09, 05:10 PM**

Quote:

30" to bottom of screen.

If you use the sub for a center channel stand how much less would the height be for the sub?

**cburbs** · **07-02-09, 05:20 PM**

My center is 9" tall.

**Mike P.** · **07-02-09, 09:11 PM**

The space between the speakers would provide enough room for a pair of IXL18's each in 12 cu.ft. tuned to 16 hz. They would provide a 4 to 5 db advantage in the 15 hz to 20 hz range over 4 15" IB's. A pair if IXL's would cost about as much as the 4 IB's. A slot port would be the easiest to implement as a 8 inch diameter round port needs to be 38 inches long and the required elbows are expensive and hard to find.

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Name: IXL IB.JPG
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**cburbs** · **07-02-09, 10:44 PM**

So what are the actual dimensions of your box?

**Mike P.** · **07-02-09, 10:54 PM**

It's 2 boxes side by side, each with external dimensions of 21" high, 26" deep, and 45" wide. It would be about 11 cu.ft. net volume for each box.

**cburbs** · **07-08-09, 01:50 PM**

If one goes the Manifold route how do you know how wide to make it - like the design in this post -

http://www.hometheatershack.com/foru...ld-thread.html

**Mike P.** · **07-08-09, 02:10 PM**

The exit of the manifold should ideally be the same surface area (or bigger) of however many subs you are using in the manifold. The width of the exit is the distance between the studs x whatever it takes to equal the cone area of the subs. The depth of the manifold is whatever it would take to mount the subs. Make sense?

**cburbs** · **07-09-09, 07:08 AM**

Nope - still a little confused on it. So say my studs are 15" apart - Use the two 18" subs you used in your last thing.

**Mike P.** · **07-09-09, 02:33 PM**

If the space between the studs is 15" then the box needs to be 15" wide so it fits between the studs. The height should be 20" and the depth 20" + whatever the depth of your studs are, either 4" if they are 2x4 or 6" if they are 2x6. So the manifold opening is 15"x 20", and the sides are 20" x 20" which is enough room to mount a 18" sub on each side.

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