My LED lights make a little hum here or there.

It seems that it's up in the attic space. Hard to get to. It reverberates throughout our tri-level condo. It's unpredictable. I recently got a new smoke detector. It's now outside our bedroom doorway. It had been 8 ft higher. When it was triggered by smoke from the kitchen it was a similar sound only prolonged. These are two short bursts.

mine was doing it for months before we finally figured out which one in what room. Changed the batteries, and it hasn't happened since, thank goodness!

Checked smoke alarms, replaced batteries still the sound …took the gd smoke alarms out of the house …still the beeping…finally found the ten year battery carbon monoxide alarm that I had put in an inconspicuous spot. That was the offender.
The sound seemed like it came from somewhere else not from where I found the alarm.

We bought our place in 1998. It might have been up there all this time. I'm going to have to call my handyman and see if he'd like to explore our attic space. We had kitchen ceiling lights installed about 20 years ago and the electrician went in via the attic space.

Thanks for sharing.

I replaced all the ones in my house 3 years ago with 10 year battery ones NOT connected to electric lines.

When those SOBs went off the shriek in the house was unbearable and I had to get to work and wreck all of them.
2 of the 6 I did dual gas detector as well, was sub $100 for all of it.

I hope that is all it is.

It's so weird. It's supposed to last ten years. The guy who installed it is from Afganistan. We had some interesting conversations. I could only express sorrow when we pulled troops out.

So many of the led lights I've installed have died long before they're supposed to. So why not this too...

though the offending unit was in sight. It kept doing the double sound bursts, even after I put in fresh batteries.
The carbon monoxide detector had reached it's ten year limit and had to be replaced to make the sound stop.

But first you'll have to find the thing! Mine plugged directly into a wall outlet and had a backup battery. Good luck!

It could be a defective implant, I would email Bill Gates.

😊

..or some kind of battery gizmo needs its batteries replaced.

Come to think of it I'm going to check my CO detector for an expiration date, thanks for the post.

I'm afraid the hunt is on. I'll report back if/when I find the darn thing.

when it is dying it will issue 5 consecutive beeps. By chance are you hearing 5 beeps?

But then repeated a bit later.

I had a similar situation years ago, and it turned out that the needle I kept on the windowsill for kids' splinters was heated enough by the morning sun to make contact with a birthday card I'd saved and kept sitting there. It was one of those musical cards, and the contact was just enough to cause a few little tweets.

It took a visit from the electric company to solve my problem.

You might have something metallic that touches something that makes a sound. Easy to check.

When the battery dies in ours or it loses power, it beeps loudly every so often (though, not as loud as a smoke detector) until power is restored or it's muted. It'll do the same thing if a window sensor loses contact.

Another thought is battery-backup devices. They will start chirping (some loudly) if there's a temporary cut in power or if the internal batteries are dying.

It doesn't really sound like either of those (and the location doesn't fit), but they're a couple possibilities I hadn't seen mentioned yet.

There are 34 condos built in 1979.

Maybe it's something that was built-in that's either been covered by a remodel or access was supposed to be provided and wasn't.

It's an interesting - if highly annoying! - mystery.