Boop?

The latest xkcd:

Mouseover title: "With a good battery, the device can easily last for 5 or 10 years, although the walls probably won't."

The joke worked for me, although I was pretty sure that a (current) MacBook makes no sound when a usb device connects. I checked, and that's true.

A current Windows 11 laptop does make usb-connect sound — but "BOOP!" is not really a good onomatopoeia for it:

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There are two distinct notes, roughly a descending fifth (at approximately 587 Hz and 392 Hz), so a monosyllabic "BOOP!" doesn't really work. And the onset of the first note is not really very stop-like, much less evoking a [b]:

It seems to me more like [ˈa.u] (= "AA-oo"), though I admit that's not nearly as evocative as "BOOP!". Commenters may have better ideas.

The only "device connect sound" I could find on the internet was this one:

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It's more complicated, and even less BOOP!-like. The video's caption is "Windows 10/8 Device Connect Sound", which may be why it's familiar, though I can't place it more exactly than "that's a familiar sound".

Maybe Randall has a laptop with a different (and more boop-like) usb-connecting sound? Or maybe he was subconsciously inspired by the new musical?

The explanation and discussion at explainxkcd are not helpful with respect to this aspect of the joke.

Update — Commenters YRG and AKMA note that MacBooks make a rather boop-like sound when connected to charging power — here's what it sounds like on my laptop:

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There are two partials, one at 880 Hz and the other at (concert A) 440 Hz, with amplitude contours that you can see in the spectrogram.

I wonder who invents such sounds, and who "owns" them (if anyone does)?