High-pitched whine

Moving to a new apartment always comes with a few surprises. Today’s surprise: noticing a high-pitched whine that I just couldn’t put my finger on. I wanted to share how I went about isolating it as the it’s not dissimilar to debugging code.

First, let’s confirm that it’s not imagined. We can use a spectrum recorder like Spectroid to visualize pitches over time.

We see a consistent pitch around 15000 Hz. So yes, the noise actually exists.

I walk out of the kitchen and the noise fades. Back in and it returns. Okay, so somewhere around the kitchen. Other sides of the walls in case it’s coming from the next room and is even louder there? No.

Presuming it’s electrical in nature (what else could cause such a pitch in an apartment?) I set about unplugging devices one by one. Microwave? No. Toaster? No. Fridge? No.

And just as I’m leaning my head under the stove range hood wondering where the plug for it’s lights are, the noise stops. Spectroid confirms it. For a second I entertain the amusing idea that the act of leaning underneath stopped the noise. Did I touch something? Ground some rogue circuit? I pull my head back and the noise resumes.

Two theories and they’re both easy to test. One, I put my head back under. No change. Two, I heard the dishwasher switch modes during the hiccup. Googling lg dishwasher 15000 hz reveals a reddit post about the same problem.

Okay, problem isolated. No obvious way of fixing the noise, but at least now I know what’s causing it.