I'm looking to get the best sound from ceiling speaker installs with out using subwoofers.

A lot of manufacturers offer a back box of some kind but I'm more interested in a proper custom built enclosure. Something that could be put in place during construction, or even retrofitted if you have attic access.

For example, I was looking through KEFs lineup and they actuallly have a chart of recommended enclosure volumes for all of their speakers. I'll use the CI200QR for this example.

[Link: us.kef.com]

They rate the frequency response at down to 35hz +/-6db with an open back. I'm guessing -6db at 35hz.

They offer a back box which measures about .5cuft. However in their enclosure chart:

[Link: kef.com]

They list 1.24cuft for "reasonable low frequency response" and 2.12 cuft for "ideal".

Far from the .5cuft back box and much smaller than an attic.

If the ceiling was 2x4 trusses on 24" centers then in theory I could put in two 2x4 braces about 48" apart, glue/screw a 2'x4' piece of plywood on top and voila. 2.12cuft enclosure. This would take very little time.

It would be even easier in a 2x10 floor. Blocking about 28" apart and your done.

With published enclosure volumes it seems like a no brainer to get the best sound possible. Does anyone do this?

Thanks.

Craig.

Edit: in this case the speaker is just over 4" deep when installed so the 2x4 truss enclosure just got slightly more complicated but nothing that couldn't be fixed quickly with some ripped plywood strips or 1x2/2x2.