Whats the best way to install in-ceiling speakers?

[KM108]

It's kinda late to ask this now, but I'm curious as to how I did. Keep in mind this is my first time installing built in speakers.

I installed 4 Klipsch CDT-5800-Cs in the upper level of the house. I found Klipsch's sheet metal enclosure designed for the speakers, calculated the volume of the enclosure, and then made my own out of 3/4" MDF. I made all 6 sides for the box. I didn't want to have the sheet rock ceiling form one side of the box. Luckily the tabs the secure the speakers are tall enough to span the 5/8" drywall and 3/4" MDF.

I then primed and painted the outside of the MDF since the boxes will be in the attic covered in blown in cellulose. (I'm in MN so at times the attic is 80 degrees colder than the house) Not sure if this was necessary, but I know MDF is like a sponge when it comes to moisture, and I figured I'll take the time to paint them now, rather than have them swell up and have to re-do them in a few years.

I figured the MDF would make a much better sounding cabinet than the sheet metal used for the Klipsh enclosure.

Lastly I positioned the boxes in the attic over the holes I cut in the sheetrock. Next I cut two 2x4s 22.5" each to fit between the rafters and alongside the cabinets I built. I drilled holes through the 2x4s and the cabinet and tied them together with bolts and locking nuts. Then the 2x4s were secured to the rafters with screws.

I also plan on using some poly-fill in the boxes. Some people may say this whole thing is total over kill for what could be considered a low/mid range speaker. However I did a quick tests with one of the speakers just laying on the ground, and one with a makeshift cardboard box cabinet. Night and day difference in sound. So I hope end up with a good finished product.

 

[GO-NAD!]

It may be a niggly point, but did you account for the decreased volume of the driver inside the box? If you added 3/4" MDF to the front baffle, it's now 1 3/8" thick. The driver sits further out of the enclosure and occupies less volume in the box as a result. I'm guessing the difference probably means very little - but more knowledgeable people around here would be able to give a more educated opinion.

It's actually not a bad idea, IMHO, as it should provide more rigidity to the installation. Just as long as you have your volume calculations correct. That actually gives me an idea for my own in-ceiling speakers, as it's on my "to do list", to install backer boxes.

As for painting the boxes, was it vapour barrier paint? If not, it won't prevent air/moisture leakage. If your house is relatively young, I assume there is a vapour barrier between the ceiling and insulation. When you cut the holes in the ceiling, you pierced this barrier. If I were you, I'd wrap the boxes in plastic sheet vapour barrier and seal the edges with appropriate tape.

 

[ParadigmDawg]

You did better than me. I just cut the holes and stuck the speakers in.

They sound fine but I just use them for background music.