High pitched whine behind drywall?| Off-Topic Discussion forum |

Crxpilot HalfDork
12/6/23 4:07 p.m.

Our 2 story home, built in 1989 has a nearly continuous very high pitched sound. When the noise does stop, it ends with 3 digital chirps (remember '90s car alarms?)

The noise is coming from the ceiling of our downstairs guest bathroom. Not near any smoke or co2 alarms. Can't hear the noise from upstairs directly above the bathroom. Are there other alarm types from the '80s or '90s that would be behind drywall?

All 3 of our current smoke alarms checked ok (installed last year and report 0 ppm co2 (lol) when tested today)

Any ideas? Driving the humans a little crazy and it makes our dogs upset.

CAinCA Dork
12/6/23 4:12 p.m.

Is there a light fixture on the ceiling? Maybe you can fish a borescope up there and see what was left under the drywall.

I'm interested to see what you find.

1988RedT2 MegaDork
12/6/23 4:13 p.m.

Wow, that's bonkers. I'd try to get a fix on the exact location, then punch a hole in the ceiling. Any lighting or duct openings nearby? How long have you heard it? Can't be battery-powered, gotta be hard-wired. How often does it stop? Always at the same time?

rustybugkiller Dork
12/6/23 4:14 p.m.

Old door bell relay still hooked to low voltage power??

Shadeux SuperDork
12/6/23 4:14 p.m.

How long have you been hearing this?

Yeah, what CAinCA said.

Crxpilot HalfDork
12/6/23 4:21 p.m.

Hearing this more often and it started ~2 months ago. I haven't timed it yet.

The old doorbell did have a fancy 1989 panel with radio but it's been removed and was always located 30 feet away in the dining area anyway.

Small bathroom with 1 small a/c vent, 1 vent fan, and one recessed can light fixture over the sink. I don't have a borescope but can borrow one from my fleet mechanic friend.

Edit for vid link: https://drive.google.com/file/d/1KR7jMT23FDyv39lyZxAWh3EghsyoKsEe/view?usp=sharing

mtn MegaDork
12/6/23 5:13 p.m.

Water leak detector?

I've found that I am really not very good at finding where a high pitched noise is coming from. You may want to extend your search beyond where you think it is coming from. You may want to have someone stand in the bathroom where you hear it and start switching off circuits one by one to see if it stops. Maybe shut off the water to the house too, see if that stops it.

Dusterbd13-michael MegaDork
12/6/23 5:17 p.m.

Are you sure it's not somebody trying to contact you in Morse code that your car's extended warranty is about to expire?

Steve_Jones UltraDork
12/6/23 5:18 p.m.

Video won't load on an iPad, but the only alarm I ever had that ended with 3 chirps was a water alarm. No clue why it'd be behind drywall, but who knows? Can you pop out either vent and see anything?

Crxpilot HalfDork
12/6/23 5:30 p.m.

I bet you guys are right. Been a homeowner since 2003 and didn't know about water alarms.

TIL...

wae PowerDork
12/6/23 5:35 p.m.

Did you have any house guests with a mischievous streak a couple months ago? Sneaking a little device to make random noises into a heating duct or something sounds like something I would totally do.

93gsxturbo UltraDork
12/6/23 5:36 p.m.

If you have or have access to a FLIR, poke around in the area where you think the noise is originating from and look for some warmth. If its electrical, it should be making a little warmth.

Is it possible the noise is in the basement and travelling up the ductwork?

Also - kill circuits until you get the noise to shut off, then start backtracking based on the circuit labelling. If its a modern house the wiring is (hopefully) reasonably compartmentalized.

jgrewe Dork
12/6/23 5:44 p.m.

The battery on a Nokia 3110 would last that long on one charge. Might be one lost by the drywall team finally going dead.

Crxpilot HalfDork
12/6/23 5:50 p.m.

Short story epilogue... 2 teen sons taking showers upstairs without the shower curtain pulled closed. Water got down and into a crack, under the floor, onto a sensor stuck up there somewhere. It did its job. Thanks all for the input!