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> It turns out that the song contained one of the natural resonant frequencies for the model of 5400 rpm laptop hard drives that they and other manufacturers used.

> The manufacturer worked around the problem by adding a custom filter in the audio pipeline that detected and removed the offending frequencies during audio playback.

Does this mean that every machine with a hdd has the same problem? Is it just about finding the right song or do engineers include some kind of dampeners to prevent this?

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In fact, almost everything has this problem.

There seems to be (someone more knowledgeable please correct me) no way to avoid having a resonant frequency. The only thing that can be done is to change it.

The resonant frequency of a glass can shatter it. The resonant frequency of a room can make it uncomfortable to be in. The resonant frequency of a bridge can tear it apart.

We even have to take special precautions between 2.4GHz wifi and processors running at a 2.4GHz clock speed because they are capable of hitting the exact same frequency.

As someone pointed out, the difference in manufacturers would have made the resonant frequency slightly differently between the specific drives.

A famous example is the old Tacoma Narrows Bridge[1].

[1] https://en.m.wikipedia.org/wiki/Tacoma_Narrows_Bridge_(1940)

> The only thing that can be done is to change it.

You can also dampen the resonance, to limit its response at the resonance frequency.

Yes, but that’s a mitigation technique and not about eliminating the resonance frequency itself.

That's just so cool.

And probably very annoying for a lot of people.

One example of a precaution taken: Spread-spectrum clocking.

Perfectly clocked signals have really high EM spectral peaks (noise radiated at particular frequencies). You can intentionally make the clock a little worse, spreading that radiation over more of the spectrum, and it will reduce the chance that those peaks break other things.

https://www.microsemi.com/document-portal/doc_download/13543...

I had a DVR (digital video recorder) that was constantly recording the video feed into hard drive. It was in my bedroom. One day when I was cleaning I moved to box and didn't think much of it. Then in the evening I was getting ready to sleep and on the side of the bed where I sleep I could hear extremely loud boomy sound. It was driving me crazy, but as soon as I moved to find the source the sound "disappeared". Going back to bed and it's back again. I was going around the room like crazy trying to find the source, or maybe it was outside? Eventually I put my ear to DVR and noticed the sound was quite similar, but very faint. By doing this I moved the DVR and when I returned to bed the sound was gone. This was so frustrating. But I least I learned something how to find a source when something like this happens next time. Basically the unlikely positioning of DVR, my furniture and myself created loud resonance.

I'm curious if this is really the answer and not something like sound tunneling and amplification.

Like when you stand somewhere further away and there is a spot were you can very clearly hear the people talking across the street or on a balcony

Natural amplification (especially through materials, which is what I would guess happened here) is resonance. It’s wild how pervasive it is.

An excellent demonstration of this is The Whispering Arch in Liverpool Anglican Cathedral or The Whispering Gallery of St Paul's in London.

>The resonant frequency of a glass can shatter it. The resonant frequency of a room can make it uncomfortable to be in. The resonant frequency of a bridge can tear it apart.

I love the roller-coaster of magnitude changes in the consequences listed: "shatter, unpleasantness, tear apart"

There’s a whole chapter in Godel Escher Bach specifically about this! (OK, so it’s supposed to be a metaphor.)

What are you referring to?

Audiophiles hate this trick

The weakness is in the specific size and shape of the drive hardware, so the exact resonant frequency would vary a bit.

But for the specific production run of hard drives combined with the specific production run of laptop casings etc, with today's manufacturing tolerances, it will be a problem.

Doesn’t that mean hearing the song from another source will still break the hdd ?

> And then they discovered something extremely weird: Playing the music video on one laptop caused a laptop sitting nearby to crash, even though that other laptop wasn’t playing the video!

Yes

Yes I read the article so I was clarifying whether or not they fixed that problem.

Seems like it would have to be vulnerable to it still, right? If their "fix" was to filter audio output. They can't filter everyone's laptops..

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