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Installing VLC Media Player voids your speaker warranty

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Re: Installing VLC Media Player voids your speaker warranty

#151

Post by dpe82 »

shawnz wrote: post #19
Jare wrote: post #5

That kind of amplitude abuse is the equivalent of pounding very hard on the keyboard for long periods of time - it will break sooner than it would normally have, and can rightfully be considered abuse. However, voiding the warranty simply because of VLC installed is, again, the equivalent of voiding the keyboard warranty simply because you are a bodybuilder. Ok enough metaphors.

If I am understanding this correctly, a specially crafted mp3 file, played in Windows Media Player or similar, could cause the same symptoms that Dell is indicating VLC could create. Surely that would be considered a totally normal operating condition that the speakers should be tolerant against. It may be heavy use, but does that mean it is abuse?

Likely not an mp3 because most of the super high frequencies that result from digital clipping wouldn't be encoded in an mp3. Most encoders do a low pass filter as their first step (getting rid of most of the problem) and then smooth out the rest of the waveform when compressing it.

It's possible, however, to create raw PCM that will destroy a lot of consumer equipment if played long and loud enough. VLC basically gives consumers a way to do that and labels it a feature.

Re: Installing VLC Media Player voids your speaker warranty

#152

Post by lutusp »

tmoertel wrote: post #147
lutusp wrote: post #133

Earlier quoted context omitted.

>> ... the resulting clipped waveform carries a lot more energy than an unclipped one. > Is this claim actually true? Yes, it is -- but it depends on how we define "clipped". > My understanding is that if you take a waveform and clip it, the resulting waveform actually carries less energy (think of the corresponding integral) Only if the clipping reduces the peak value. If you compare a sinewave with a peak value of…

> Only if the clipping reduces the peak value... I don't know of any widely used definition of "clipping", nor any definition that fits the context of this discussion, that allows for a signal's peak value not to be reduced. It's called clipping because the extreme values look to have been clipped away, as if by scissors. The parts that have been clipped away contain energy, don't they? So won't the clipped signal wi…

> I don't know of any widely used definition of "clipping",

But there is one. In electrical engineering, it's any process that arbitrarily limits a signal's amplitude. By far the most common meaning is a signal that exceeds the voltage range of an amplifier or signal pathway.

> nor any definition that fits the context of this discussion, that allows for a signal's peak value not to be reduced.

See above.

> It's called clipping because the extreme values look to have been clipped away, as if by scissors.

Yes, but this can result from trying to pass a signal too large for the circuit, or it can mean an intentional scheme in which a fixed signal amplitude is truncated, the meaning you're discussing.

In the present discussion, in which a volume setting is increased until the speakers are jeopardized, the meaning is clear -- it's an increase in signal amplitude that the amplifier cannot support, resulting in the waveform being clipped at the maximum available amplifier voltage.

> The parts that have been clipped away contain energy, don't they? So won't the clipped signal will carry less energy than the original?

Not if the signal amplitude is increased. In the present discussion, the problem is being caused by raising the volume level too high, which causes the signal to exceed the available amplifier voltage. My diagram shows this case:

http://i.imgur.com/oE5NFZ9.png

The red trace is the maximum volume setting that the amplifier can support without distorting the signal. The green trace is a much higher volume setting that essentially reduced the output to a square wave. In both cases, the peak voltage is the same.

> When you take a sine wave of peak value 1 and clip it, what you get is not a square wave with a peak value of 1.

That depends on how you define "clip". If you increase the size of the sinewave, clipping takes place at the maximum voltage. If you clip by reducing the possible range of voltages, the sinewave remains the same size but maximum amplitude goes down. The present discussion revolves around the first of these choices.

Re: Installing VLC Media Player voids your speaker warranty

#153

Post by tmoertel »

lutusp wrote: post #152
tmoertel wrote: post #147

Earlier quoted context omitted.

> Only if the clipping reduces the peak value... I don't know of any widely used definition of "clipping", nor any definition that fits the context of this discussion, that allows for a signal's peak value not to be reduced. It's called clipping because the extreme values look to have been clipped away, as if by scissors. The parts that have been clipped away contain energy, don't they? So won't the clipped signal wi…

> I don't know of any widely used definition of "clipping", But there is one. In electrical engineering, it's any process that arbitrarily limits a signal's amplitude. By far the most common meaning is a signal that exceeds the voltage range of an amplifier or signal pathway. > nor any definition that fits the context of this discussion, that allows for a signal's peak value not to be reduced. See above. > It's calle…

We must be talking past one another. I thought I was speaking in the electrical-engineering sense of clipping (my undergrad studies were in EE).

In any case, to make sure we're talking about the same things, I'll be more formal. Let y(t) by a time varying signal. Now define a maximum amplitude V > 0. Let us say that clipping occurs at time t if |y(t)| > |V|. Define the clipped version of y to be w(t) = max(–V, min(V, y(t))).

Now:

Claim 1: |w(t)| y(t)| for all t. That is, the clipped version of the signal is contained within the unclipped version. Proof: Follows from the definition of min, max, and V.

Claim 2: The clipped version carries less energy than the unclipped. Proof: Follows from Claim 1 and integration.

Now, here's where you lose me. The claim you made that sparked this conversation was this: "the resulting clipped waveform carries a lot more energy than an unclipped one." But this claim seems to contradict my Claim 2.

Can you show me how to reconcile these seemingly contradictory claims?

Edited to add: I'm not claiming that these claims can't be reconciled. Rather, I'm hopeful that thinking about the exercise will help us to see how we're talking past one another.

Re: Installing VLC Media Player voids your speaker warranty

#155

Post by userbinator »

fnordfnordfnord wrote: post #148
userbinator wrote: post #142

Earlier quoted context omitted.

They didn't bother to put $0.001 DC blocking capacitors on the DAC outputs? This isn't a "bug in the kernel" or any software, it's a clear hardware flaw.

Be fair, those caps are easily two or three times that much.

In relatively low quantities, yes: http://www.digikey.com/product-detail/en/CL05A105KP5NNND/CL0...

But when you're buying them in quantities that a company like Samsung would (that above link is, amusingly enough, to ones that Samsung themselves make), the price drops off rather steeply. $0.001USD is around what I can find for buying them from China in 100Ku.

Re: Installing VLC Media Player voids your speaker warranty

#156

Post by caf »

fnordfnordfnord wrote: post #140
caf wrote: post #135

Earlier quoted context omitted.

It is not that simple. The speaker is a dynamic system whose response to signals is not memoryless. A speaker that can easily handle a pure 4kHz tone at the maximum amplitude cannot necessarily also handle a 4kHz square wave at the maximum amplitude (a square wave distributes much of its power into harmonics). It is well known that you can destroy speakers just as easily by overdriving the output stage of the power a…

>Of course, Dell could include analogue filtering circuitry to filter out the excess power in inaudible frequencies if they wanted to. It likely isn't necessary as it is probably built into the output amplifier. I have no clue what audio amplifier dell used but here is an example of a typical headphone amplifier IC http://www.ti.com/lit/ds/symlink/lm4881.pdf If you look on page 9 of the datasheet you'll see its frequ…

The lack of response of the speaker is the problem. If the power at those frequencies isn't being efficiently converted into sound, it's being converted into heat instead.

Re: Installing VLC Media Player voids your speaker warranty

#157

Post by jrockway »

jbk wrote: post #41
brador wrote: post #36

Earlier quoted context omitted.

How about detecting Dell Speakers and automatically setting the max volume to 100%, with a notification so the user can give an a-ok if they want to go higher. That way, at least users know and can make a decision. Similar to the Android warning if you set your volume too high that it could cause hearing damage. I'd prefer to be warned rather than surprised by this!

> How about detecting Dell Speakers How would you do that? And no, this is not specific to VLC.

Pump DC into the speakers at full power, and pop up a dialog asking the user if their speakers have melted yet.

Re: Installing VLC Media Player voids your speaker warranty

#158

Post by philliphaydon »

aestra wrote: post #49
philliphaydon wrote: post #21

Earlier quoted context omitted.

Not sure if you've ever owned a Dell laptop, but I'll never buy one again. On a couple of occasions I have tried to play DVD's on them and cannot hear people talking with the volume up. Put headphones on and its too loud. Dell speakers are junk.

Um in my experience all laptop speakers of all brands are like that.

I run Windows 8.1 on my MBP/r and don't have that issue at all.

External DVD Drive, play one of my DVDs on the Mac, audio is perfectly fine.

Play the same DVD on my Asus UX31, cannot hear the people talking, use VLC player to up the audio to 125% and its fine.

Re: Installing VLC Media Player voids your speaker warranty

#159

Post by [deleted] »

humbledrone wrote: post #117
slacka wrote: post #104

Earlier quoted context omitted.

Dell may be using poor quality parts. VLC can also make the sound louder than any other media player that I've used while generating destructive square clipping. The problem is it's too easy to set the volume above 100%. I've done so with the mouse wheel. And I now have a $2000 out-of-warranty laptop with blown speakers. Fixes could include: * Not remember settings above 100% between sessions unless an advanced optio…

Audio is generally handed over to the OS via a format called Pulse Code Modulation. This is a series of audio "samples", which in the Windows case are individual signed 16-bit integers. Typically each second of audio is broken into about 44,100 of these integers. Each integer represents the sound amplitude during a particular 1/44,100th of a second, with a large negative number (-32,768) being a small amplitude and a…

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