On Mon, 25 Apr 2016 09:53:05 -0700, Don Y
wrote:

I want to install a couple of these:
https://www.security.honeywell.com/hsc/products/intruder-detection-systems/Sounding-Devices/wave-indoor-sounder/21674.html
*inside* the house, tied into the alarm and "fire" systems.

But, don't want to *see* them (i.e., hanging on a wall).

The only two options that come to mind are to:
- set them *in* the ceiling behind a decorative grating/grillwork
- fasten them to the interior of a closet (and expect some
attenuation due to the closet door being closed

3) I already had a piece of weaving hung on the wall, maybe 1' wide
and almost 2' high, when I wanted to put in glass/wood breakage
detectors. One facing the back of the house, one facing the front. I
didn't mind if they showed but the hanging was already there, so put
it in and put the hanging back, over it, and it works fine and can't
be seen. Things a lot denser than a weaving would probably work
too.

Inside a duct would also be good -- probably REALLY good as it would
also serve as an acoustical conduit -- but I think disallowed (code).

Note that the enclosure is essential to the performance of the
device as it is, in effect, a folded horn.