This seems to be an ongoing question from a lot of newbies (including me.) I jumped into X10 last month. Now, I'm noticing all the challenges it has. I currently have 5 powerhorns, which even inside aren't really that loud. I guess it has to do with the size of the house too (mine is about 3000 sf.) Outside, they sound like loud crickets. Like you, I must have good insulation. Fortunately, I have an older alarm (wired into the house), which has a loud outside horn, so when I leave the house, I turn on two alarm systems.
Of course, I'd like to do away with that, so I'm looking for a way to have a outside horn that would be triggered by the X10 system, but that would also stay on for longer than the max 4 minutes that the console leaves them on for.
There was a recommendation on a different thread about how to modify a powerhorn to trigger another siren. Unfortunately, it only works with the older powerhorns. I took mine apart and didn't see what the mod was talking about. See the following topic:
http://forums.x10.com/index.php?topic=17381.0I've read about people using an "aftermarket" horn, but I still don't know which they're talking about.
Personally, I continue to look into this because of the investment I've made so far and the home automation part of X10. However, I was very disappointed when I found out that the console can't even flash the "security lamp" anymore because they've re-engineered the lamp modules to have a "soft start", which causes the lamp to light up slowly (from 0 dimming to 100), but never gets to 100 because the console sends on/off commands to close together.
If you do find something, please share it. I'm interested.
Thanks,
Frank