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Installing VLC Media Player voids your speaker warranty

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201–210 of 224 posts

Re: Installing VLC Media Player voids your speaker warranty

#201
post #156

Earlier quoted context omitted.

>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.

But those frequencies don't get to the speaker 'cause the amplifier doesn't send them...

Re: Installing VLC Media Player voids your speaker warranty

#202
post #15

As the main developer of VLC, we know about this story since a long time, and this is just Dell putting crap components on their machine and blaming others. Any discussion was impossible with them. So let me explain a bit... In this case, VLC just uses the Windows APIs (DirectSound), and sends signed integers of 16bits (s16) to the Windows Kernel. VLC allows amplification of the INPUT above the sound that was decoded…

Aside from Dell's crappy hardware, wouldn't it be possible to just compress the sound more so quieter passages would become louder but those passages already near the maximum wouldn't get clipped? That should definitely sound better...

Re: Installing VLC Media Player voids your speaker warranty

#203
post #182

Earlier quoted context omitted.

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 ) = ma…

Here's the first crossroad, where we diverge: > Now define a maximum amplitude V > 0. The problem being discussed is one in which the user cranks up the volume such that the maximum volume level is far exceeded, and the amplifier circuit, which cannot reproduce the higher level, instead clips the waveform at the supply voltage. > The claim you made that sparked this conversation was this: "the resulting clipped wavef…

OK. I think I see where our signals are getting crossed. I look at your diagram and think, The green signal g is not what you get when you try to output the red signal r but the output stage clips it at the supply voltage (my V). Rather, the green signal g is what you get when you take the red signal r, amplify it by A = Infinity, and then try to output that new signal rA, which the output stage then clips.

For all A > 1, |rA| > |r|. Therefore, I have no problem agreeing that a clipped rA carries more energy than the original r. (In fact, this is just saying that bigger signals carry more energy, regardless of clipping.)

To me, your original statement read as though it made the following claim: If your amplifier tries to output a signal r but clips off the peaks, what you get out is a signal that carries more energy than r. (This is the claim I found hard to believe.)

But what you really meant (I think) was that, if you take a sine wave as input and, as a human controlling the volume knob, keep turning up the volume until the sine wave's maximum amplitude so far exceeds what the amplifier can reproduce that it comes out looking like a square wave, then that square wave carries more energy than the original, un-volume-adjusted sine wave. Is that what you meant?

If that's what you meant, I have no problem believing your claim. It's just that I wouldn't call turning up the volume knob to be part of the "clipping" process, but rather amplifying. When you turn up the volume knob, what you get out is always a "bigger" signal, even if it's clipped.

Re: Installing VLC Media Player voids your speaker warranty

#204

Earlier quoted context omitted.

It's exactly as easy to decrease VLC's audio level back to normal as it is to increase it. Anyway if you don't like it remembering the last audio level, go to Tools > Preferences > Audio, check the "Always reset audio start level to" box, and set it to 100%. Voila!

No, VLC should remember the last audio level, just not when it's over 100%. If I leave it at 50%. On next restart it should be 50%. If I'm watching a movie and finish on 200%, on next restart it should be 100%. Clipping sucks. VLC shouldn't remember these options unless the user changes an optional setting.

Jesus christ, what you really want is the moon on a stick.

Re: Installing VLC Media Player voids your speaker warranty

#205
post #184

Earlier quoted context omitted.

Remember that each technical measure you add to a design represents another (a) cost (b) size/weight, and (c) possible failure mode. > When the running average surpasses a value that indicates the speaker is reaching its limit, cut the volume. I take it that this doesn't work? No, it might work, but it's really a question of cost, complexity and represents an added failure mode -- something else that can go wrong.

In my opinion, it should be impossible to physically damage a computer from user-space code. I'm surprised that this seems to be such a controversial opinion. Given that, a computer which allows random audio API clients to destroy the computer's speakers is not correctly designed. Certainly, it may add cost, size, and weight, but if that's what you need for correctness, then that's what you need for correctness. The…

> In my opinion, it should be impossible to physically damage a computer from user-space code. I'm surprised that this seems to be such a controversial opinion.

I don't find that controversial at all, but as time passes, it seems there are more ways that user activities can bring a computer down. The most obvious way is by sending out-of-bounds signals to storage devices that can erase or even physically damage them, but this example of destroying speakers, even though it should not be allowed to exist, seems plausible also.

Re: Installing VLC Media Player voids your speaker warranty

#206
post #182

Earlier quoted context omitted.

Here's the first crossroad, where we diverge: > Now define a maximum amplitude V > 0. The problem being discussed is one in which the user cranks up the volume such that the maximum volume level is far exceeded, and the amplifier circuit, which cannot reproduce the higher level, instead clips the waveform at the supply voltage. > The claim you made that sparked this conversation was this: "the resulting clipped wavef…

OK. I think I see where our signals are getting crossed. I look at your diagram and think, The green signal g is not what you get when you try to output the red signal r but the output stage clips it at the supply voltage (my V ). Rather, the green signal g is what you get when you take the red signal r , amplify it by A = Infinity, and then try to output that new signal rA , which the output stage then clips. For al…

> It's just that I wouldn't call turning up the volume knob to be part of the "clipping" process, but rather amplifying.

But it is, indeed it's the most common example of clipping in engineering practice. Consider two alternatives -- one in which the amplifier is able to accommodate a great increase in volume without any distortion, and another in which it cannot.

In this image:

http://i.imgur.com/g8txTmC.png

The blue trace represents maximum normal volume (100%). The green trace represents a system in which the amplifier can accommodate a great increase in volume setting (200% of normal), simply because its power supply voltage is at least twice as high as that required for 100% volume. The red trace represents a system that cannot tolerate any volume settings greater than 100%.

In this diagram, the 200%-volume green trace has a higher subjective volume level than the 100%-volume blue trace (i.e. twice as high in voltage, four times as high in speaker power). The red trace, which would sound very distorted to the user, also has a higher power level than the 100% trace, but less than the green trace. The red trace is typical of systems that are limited to 100% volume by power supply voltage.

The red trace represents the most common example of "clipping" as it takes place in actual equipment and in engineering practice. Its output has more energy than the blue trace, and less than the green trace.

-- former NASA engineer

Re: Installing VLC Media Player voids your speaker warranty

#207
Possibly relevant anecdote...

I once acquired an audio geologic recording of the tragic Christmas Eve tsunami in Indonesia. It was an interesting listen, with a lot of bass/sub-base frequencies. Played at what seemed a reasonable listening volume, it managed to destroy my iPod headphones. Seems some sounds can be inherently damaging to less robust equipment when seemingly operated well within sensible limits.

(The replacement of said headphones cemented my appreciation of Apple: at a time Apple wasn't selling headphones alone, upon my consternation of not being able to buy a set, a clerk ripped open a random box and handed me new headphones gratis.)

Re: Installing VLC Media Player voids your speaker warranty

#208
post #194

Earlier quoted context omitted.

Dynamic audio power limiting introduces a whole host of audio distortions that would cause your computer to lie to you by not playing what you told it to. Your computer lying to you is a problem in principal I think, but specifically if you're doing any kind of sound editing/composition it's a huge problem because now you can't know if what you're hearing represents what you're creating or if your os or sound card ha…

Your computer's already lying to you by piping your audio through crappy speakers. Is the distortion actually going to be worse with a limiter in place? I really don't understand, why do you think this functionality doesn't belong in the OS or the hardware? To me, you're basically saying that you're OK with giving arbitrary web sites the ability to damage your hardware, since that's effectively what that ends up impl…

For really bad audio, no. For otherwise perfectly fine audio, yes.

Re: Installing VLC Media Player voids your speaker warranty

#209
post #100

Earlier quoted context omitted.

Cheap shit. Seriously, cheap shit. There are several ways to solve this, all of which boil down to "use more chips" or "use better speakers", thus increasing the price of already incredibly shitty speakers. Source: I'm involved in designing consumer electronic products and the only corners that don't get cut are those that, if cut, result in certifications not being granted and therefore in products you're unable to…

This is great information - and I'd love to know which speaker manufacturers you approve of. I'd rather own an expensive set of desktop speakers that lasts ten years than deal with Dell parts breaking all the time.

Get a pair of these. Don't pay more than $40 for the pair. They are quite decent, especially at this (retail) price point. Dayton Audio B652 6-1/2"

Re: Installing VLC Media Player voids your speaker warranty

#210

Earlier quoted context omitted.

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.

I left the reply in jest. But while we're here. Capacitors vary widely in price by type, capacitance, and quality. A 1uF multilayer ceramic is probably one of the most common and cheapest to buy capacitors there is, except maybe the .01uF. Output coupling of an audio amplifier requires a lot more capacitance than ceramics can muster. That cap, if present is going to be an electrolytic, and it is going to cost more th…

I have the schematics for my laptop and it has 1uF ceramics on the speaker PA inputs, that's why I linked to that particular one. The other common values I've seen are 2u2 and 4u7, which is a little more expensive but will give more bass --- not that it really matters on a tinny little laptop speaker anyway. At least I'm happy to know that I won't burn out the speakers on my laptop with DC.
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