Our bedrooms are all upstairs so we use a baby monitor after Edie goes to bed and we hang out downstairs with the stereo or TV on. The reciever is set up so that it doesn't activate unless noise levels elevate above the norm in Edie's room. For example, we often have Edie sleep to white noise, but because the white noise is at a constant level, it doesn't turn the receiver on downstairs and we don't have to hear static while watching TV. Sometimes if Jeff walks by her room, the noise of his shoes on our wood floors will turn the system on downstairs and I'll hear his footsteps on the receiver. When the downstairs receiver activates, it lights up with little LED lights, 1 light for minimal noise, 4 for an epic scream fest.
I was remembering today this one time that Jeff decided to take on a personal challenge - to see how hard he would need to smack my butt before it set off the monitor. As in, the monitor in Edie's room upstairs would have to hear him smacking my rump all the way downstairs (we were standing in front of the receiver) and turn on the whole system from the noise.
It took 3 tries.