I'm wondering how X10 receptacles and appliance modules (and in-line modules, too) work. Are they mechanical relays, or some kind of SCR (or other semiconductor) switch? What I'm getting at is audible noise. I have seen other posts on this forum about noise, and am wondering about it.

I need to have on/off (don't need dimming) control for some devices in a media room. So, I'd like to consider the noise as part of the selection criteria for X10 devices. A single loud click when power on or power off is less bothersome than continual loud hum.

What can I expect from appliance modules, receptacles, or inline modules in the way of noise? Click or hum? Loud enough to be noticable during movie or music listening? Does it typically vary by manufactufer?

Thank you for any comments.

DG