IB Question

[Conrad.]

All,

I'm getting seriously tempted by the idea of an IB system but I have a couple of questions before I can decide fully.

As I live in rented accommodation, I can't go cutting holes in my floor, wall or ceiling; at least not without seriously annoying the neighbours upstairs. So, I was thinking, would it be possible to build an IB type setup but just have it open to the room. Say, for example, I built a box that had four sides and a base with a 12" or 15" driver in three of the sides. Would that still work? I realise that the drivers would actually be pressurising both sides of the "baffle" but as long as the room is large enough that shouldn't provide any of the compressions springiness that you get with sealed or ported designs, right?

It might not look pretty but would it work?

I then got to thinking some more about it's aesthetic issues (a large open box with exposed drivers and nothing covering it's innards!). I noticed that Otto had put a beautiful grill over his fantastic looking IB enclosure and I thought the same could be applied to my hypothetical set-up. As long as the combined space available through the holes is more than half the total active area of the drivers, should everything be ok? What about other designs, like a lid that's suspended a few inches about the main box, leaving a large gap for the air to move through?

Have I missed the point completely?

Thanks

[Rodny Alvarez]

I built a IB but I'm not an expert on the design, what you trying to build I think it would be a OB or dipole sub woofer instead of a IB, I've seen some people at the cult with a setup where the subs are mounted on a board, its not just a board you need to know what to do, (I don't), other design I've seen... when they put the drivers mounted on the closet door, and used the closet as a box.

With the IB you need to make sure the front wave its completely isolated from the back.

http://www.diysubwoofers.org/dipole/design.htm

[Sonnie]

We have a pretty good thread on IB as well...

What is an IB...

BUT... it doesn't sound like you can accommodate an IB. If you can build a bit box... an LLT would be best for you and you'd most likely get better extension.

LLT Explained

Rodny coverted his IB to an SLLT and couldn't be happier, I don't think.

IB Makeover

[Conrad.]

Thanks guys.

I've read those threads with interest but I wasn't quite sure about the neccesity of having the opposite sides of the drivers pressurising completely different spaces. I now understand (I think) that it's to do with the amount of time/distance between the air movement from the two sides interacting with each other.

I was hoping to build a box that I could then fix into a space when I move into somewhere I can cut holes in! THinking about it, the odds of getting the dimensions to match exactly are pretty slim so I'll probably just hold off until I've got the right environment to begin with.

The idea of a LLT (or even an SLLT) is growing on me though.

Thanks

Conrad

[WmAx]

One feasible option you seem to have overlooked is to pick a room with a door that opens into your listening room. Buy a new door that fits the room, and place the old door in a closet out of the way until you move out. Install the drivers in the new door. Be certain to use the most solid door you can find, and install closed cell weather stripping on the door jam to minimize leakage. Also mount an under-door seal(I forget the proper name for these) to reduce leakage. Of course, you have to be willing to have an odd looking door. On the other side of the door, you can make it less ugly in the next room by building a wood frame to extend the back of the door by about 8"-10"(or whatever minimum distance is required to clear the back of the driver), and applying a fabric that matches the room.

-Chris