[HN Gopher] Can *YOU* blow a PC speaker using only a Linux kerne...
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Can *YOU* blow a PC speaker using only a Linux kernel driver?
Author : TangerineDream
Score : 55 points
Date : 2021-06-18 17:25 UTC (5 hours ago)
(HTM) web link (nakedsecurity.sophos.com)
(TXT) w3m dump (nakedsecurity.sophos.com)
| EamonnMR wrote:
| I've definitely blown PC speakers with softsynths before so it
| should be possible in principle.
| jancsika wrote:
| What would happen if you sent a random stream of ones and zeros
| to the PC speaker? Wouldn't that be equivalent to the PC speaker
| producing square waves at all the frequencies which it can
| produce?
|
| At least if wearing it out in the fastest manner possible counts
| as "blowing" it, that could work...
| schaefer wrote:
| In the late 90s and early 2000s, I remember two distinct
| occasions where a computer tried to play a data cdrom as if it
| where an audio CD through my headphones.
|
| Easily one of the more unpleasant experiences of my life (and
| I've broken bones). Something about the sound triggered a very
| specific Synesthesia. I smelled a burning smell for half a day.
|
| So... in addition to blowing speakers, you can also blow minds.
| yjftsjthsd-h wrote:
| So the takeaway here is that you should not attempt to fuzz a
| human brain while using it:)
| timw4mail wrote:
| Now I wonder if a piezo beeper would be more plausible or less
| plausible to blow?
| capableweb wrote:
| PC Speakers commonly are piezo beepers, but that's probably
| "recent".
| timw4mail wrote:
| Well yes, but peizo beepers were much less common when the PC
| speaker was commonly used for games, or just as the main
| sound output.
| Someone wrote:
| Reference: https://en.wikipedia.org/wiki/PC_speaker
| londons_explore wrote:
| piezo beepers typically have a resonance frequency where they
| are _much_ louder.
|
| Run it at that frequency for too long and the pizeoelectric
| coating delaminates from the metal disc of the speaker, leading
| to failure.
|
| So, yes, you can probably blow them from software if you're
| willing to have it turned on for a few days continuously.
| timw4mail wrote:
| I wonder if moving iron beepers would have the same issue.
| Either way, seems like a lot of effort.
| frostyiguana wrote:
| All I can say in my early Linux years is I tried to redirect
| /dev/cpu to my speakers (maybe something in /dev/snd), and it
| made one of the loudest sound my quite huge speakers could make.
| and volume wasn't so high..
|
| I tried that because I was curious, since everything is a file,
| then surely cpu processing things to become a sound right ? :)
|
| (if you try this please make sure to get that into a pcm/wav
| file, and reduce the amplitude of that file _first_)
| carrja99 wrote:
| lol I did this too eons ago. I don't think those speakers ever
| worked the same again after that.
| dlevine wrote:
| This reminds me of Godel Escher Bach. "I Cannot Be Played on PC
| Speaker X."
| throwaway789657 wrote:
| Why don't all speakers have some circuitry that blocks any signal
| that could blow out the speakers? This has always seemed like an
| absurd state of affairs. It should not be possible to damage
| speakers by turning the volume too loud.
| kube-system wrote:
| It's mostly a matter of matching the output characteristics of
| the amplifier to the capability of the speakers... which is
| what most consumer products with speakers do. Note that the OP
| concluded that it likely wasn't possible to blow the PC
| speaker.
| throwaway789657 wrote:
| If you have your own receiver and your own speakers--a home
| stereo system, not a PC speaker system--it is just a matter
| of turning the nob too high to blow them out. With all these
| wifi-connected receivers these days, I bet if your laptop is
| compromised, a hacker could turn up the volume and physically
| damage your speakers. Anyone inside your wifi can cause many
| thousands of dollars (or whatever your speakers cost) of
| physical damage. Wow!
| londons_explore wrote:
| Because knowing exactly how much signal is too much is really
| hard.
|
| When using the speaker, for some purposes you want absolutely
| max volume - that involves getting the physical parts of the
| speaker moving fast and far. Yet move them slightly too fast or
| too far or do that too often and it'll physically break. Odd
| effects like resonance mean two very similar looking signals
| can have widely different physical effects.
|
| The ideal threshold might depend on numerous factors, like
| temperature and pressure, the age of the speaker, etc. Easy to
| do in software, impossible in hardware.
|
| So why not just have more margin and make the line between
| 'loud enough' and 'breaking apart' wider? Well to do that your
| speaker would need to be physically larger, and space is very
| much in a premium in many devices.
| throwaway789657 wrote:
| In no other high-end consumer product would that
| unreliability be tolerated. Why would you ever run your
| speakers at a volume that might blow them out depending on
| what the next bar of the song sounds like? Are you pre-
| screening every single bit of audio that will get played over
| your speakers? Otherwise, you should _never_ run speakers at
| a borderline volume. This protection should be built in to
| the speaker. No matter how much volume you feed into a
| speaker, it should not break.
|
| (Of course, you could feed always feed such an absurd amount
| of power that it would break even the protective circuits,
| but that ultimate vulnerability is just inherent in the
| nature of electronics).
| walshemj wrote:
| It happens with DJ sound systems and Band PA's
| throwaway789657 wrote:
| So this poor reliability is just rampant in the sound
| industry? Unless there is some reason why such a circuit
| is not feasible without, e.g., decreasing sound quality.
| Which is the kind of thing my original question is asking
| about.
| grawprog wrote:
| When I worked at my old shop I blew out 3 different CD
| changer stereos and two sets of speakers. One of them even
| ended up slightly catching on fire...well it was smoking
| anyway...The machines were really loud, you needed to crank
| that shit if you wanted to hear it...also I learned that
| you can't plug 3 sets of speakers into a single one of
| those things.
| mcraiha wrote:
| Related, VLC Media Player destroyed Dell speakers thread
| https://www.dell.com/community/Laptops-General-Read-Only/VLC...
| jolmg wrote:
| I wouldn't blame VLC. Here's the response from main VLC
| developer:
|
| https://news.ycombinator.com/item?id=7205875
|
| I agree with them that when using the official API for
| whatever-X, you can't be blamed when X fails. Whatever X is, it
| should be built to cover all uses of its official interface.
|
| In the case of VLC, that X is the Dell sound hardware, which
| can't handle certain uses because of a power incompatibility
| between the Dell sound card and the Dell speakers.
|
| Reminds me of a case long ago where a GUI program took blame
| because it sometimes caused the X11 server to crash. That was
| clearly a bug on the X11 server side, too. A server should be
| built such that it's impossible for a client to crash it.
| josefx wrote:
| > That was clearly a bug on the X11 server side, too. A
| server should be built such that it's impossible for a client
| to crash it.
|
| Not sure X11 itself was to blame for most crashes. GPU
| drivers tended to be hit or miss in the past and if I
| remember correctly even Microsoft had enough of that mess at
| some point and started to isolate them from its otherwise
| monolithic kernel, just so it could at least recover the
| session instead of blue screening.
| kevingadd wrote:
| I always get a little nervous when really messed up audio
| gets sent through my semi-expensive speakers... "are they
| designed for this? did I just ruin them by playing a game
| with a buggy audio mixer?"
| jolmg wrote:
| The audio mixer is dependent on the speakers, not the other
| way around. The speakers should be able to handle anything
| the mixer is able to throw at it. If they aren't, that's
| fault on the speakers' part.
| bob1029 wrote:
| I think this is a grey area depending on your setup and
| listening preferences.
|
| I have ~2kW of RMS amplification available to my
| floorstanding loudspeakers and subwoofer. There is a lot
| of DSP/EQ protection in between my HTPC and the
| mechanical drivers in the speakers.
|
| Despite all of this, I have had incidents where the
| software glitches out and plays the un-decoded DTS/DD
| stream. If you have your volume set at or near reference
| when something like this happens, it can cause physical
| damage (to both your speakers and your ears).
|
| (Audio) Engineering is all about balancing many complex
| factors. Mistakes happen and you can't address all of the
| edge cases without ruining the overall user experience.
| To say its the fault of the speaker is a little bit
| accusatory in my opinion. Can you ruin your car by taking
| certain actions? Certainly. Is this the car's fault? No.
| [deleted]
| nitrogen wrote:
| To add to this, depending on the amplifier design you
| might get better linearity (less harmonic distortion) by
| significantly overprovisioning power.
| yrral wrote:
| Related: In the past Apple released a bad bootcamp sound driver
| for macbooks that caused windows to blow the laptop speakers. So
| technically you can blow some speakers with bad drivers
|
| https://www.extremetech.com/computing/240309-apples-bootcamp...
| https://forums.macrumors.com/threads/15-2016-mbp-speaker-cra...
| https://www.reddit.com/r/apple/comments/5e1g37/warning_bootc...
| hutattedonmyarm wrote:
| The article seems to be about those tiny PC speakers which beep
| out BIOS codes, not those types of speakers used to output
| actual OS sounds and music
| anonymousisme wrote:
| One possible way to approach this would be to write a simple
| function generator (square wave) and sweep it across the audio
| spectrum, while also recording the speaker output level by way of
| a connected microphone. The resonant frequency of the speaker (or
| the microphone) should be observable as the peak amplitude seen
| by the mic. Once known, just set the generator to that frequency
| and blast away for a while.
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(page generated 2021-06-18 23:02 UTC)