[atledreier]

Finally got the chance to try an IB. Been wanting to for years. The road here has been long and winding, but I've finally pulled the trigger on four IB318. I have two Behringer EP4000 to drive them, but "everybody" keeps telling me it'll be too much power and I will blow them. We'll see how it goes. I'm a fan of overkill, so I think two amps running near idle will sound better than one amp strained just to protect drivers.

I have to make a pretty big compromise on placement, but it's worked before in a very similar circumstance (LLT sonotubes in the back).

The room will get a new wall in the back (open to a storage now) and the IB will go in this wall. I'll make a manifold for all four drivers in a dual opposed configuration.

Drivers are currently being built.

 

[Mike P.]

As long as you're careful you should be fine. One EP4000 will take them to Xmax at 16 hz assuming a 600 cu.ft. backspace.

 

[atledreier]

Yeah, but two will have far better damping factor and headroom where excursion isn't an issue.

A 10Hz highpass, while not encouraged in IB installs, can do wonders for low frequency excursion in the single digit range.

 

[atledreier]

Currently contemplating wall stiffening. I think I have a good solution, please feel free to shoot it down if I make some gross errors here. The wall is a double wall since there used to be a cold storage in the back room. Rebuilding this wall as a double wall with a layer of 11mm textured MDF on either side. The studs will be braced with plywood sheets to improve stiffness and hopefully get the resonance up into a treatable range.

 

[Mike P.]

Looks good to me.

 

[atledreier]

I was hoping you would say that!

I'll be sure to get some pictures of the process. Whole room is in redesign mode at the moment.

 

[ellisr63]

Question: Wouldn't it be better to only attach the box to one set of 2x4s and then attach to the floor? I'm thinking to stop the transfer os sound from one room to the other... Or does it not matter with a IB setup?

 

[atledreier]

No, since the drivers are literally playing in both rooms there is no way to prevent the transfer anyway.

 

[ellisr63]

Currently contemplating wall stiffening. I think I have a good solution, please feel free to shoot it down if I make some gross errors here. The wall is a double wall since there used to be a cold storage in the back room. Rebuilding this wall as a double wall with a layer of 11mm textured MDF on either side. The studs will be braced with plywood sheets to improve stiffness and hopefully get the resonance up into a treatable range.

By building a box that fires the woofers at each other will this reduce the wall vibration compared to attaching the woofers side by side to the wall?

 

[Mike P.]

Yes, opposed drivers will cancel each other out.

 

[Savjac]

Good Luck on your journey, this sounds pretty exciting.

My new home is one that would allow me perfect access and build space for an IB but I am just too askered to try it. :gulp:

 

[ellisr63]

Yes, opposed drivers will cancel each other out.

But it will not lower the output, just reduce the vibration... Correct?

 

[Mike P.]

Yes, that is correct.

 

[Michael M]

Array IBs can really benefit from bracing as all woofers are going the same way at the same time. Based on my experience, I'm not sure any extra bracing needed for a manifold. I had mine in my attic, my brother did one in his in his floor, neither one of us used extra bracing, and we had no issues due to exactly what Mike P said, the vibration is cancelled out. All you get is sound.

Then again, there are other benefits such as the sound not going into other parts of the house through that wall.

 

[atledreier]

Little activity this weekend.
Drivers are STILL being built, apparently.
Decided to flip the room so I get the IB on the front wall. The layout will also let me utilize the rest of the room better.

Went from this:

To this:

 

[blitzer]

Bracing the wall will help in the sense that bracing any wall in a home theater can help. Do you want a big wobbly wall that resonates and could contribute to muddy sound and vibration throughout the house? I vote no. Even one or two braces down to the floor can make a significant difference in the stiffness of the wall. Nice thing is...you can do this later

 

[atledreier]

Yeah, the wall is made, and I skipped the braces, actually. As you say, I can do this later if need be.

Right now I'm still waiting for drivers, but I'm experimening with speaker and listening positions, as well as treatments, so I've got some stuff to do while I wait.

 

[atledreier]

Drivers finally came in, and MAN are they some beasts. There's something special about long excursion 18" drivers, like a big block V8. There's no replacement for displacement...

 

[blitzer]

Finally! I have the same ones and it took a long time for them to be built as well. You fully installed? Test run yet?

 

[atledreier]

I've had a very quick testrun and a very quick calibration run. Initial impressions seem to match my expectation. Very deep, they dig alot deeper than my old LLT sonotubes with a 13,5Hz tuning, and they just draw so little attention to themselves it's incredible. The bass is just there, effortless and powerful.

Can't wait to have them run a few hours and start to calibrate them properly.