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On a laptop purchase from a reputed store, I was instructed not to use VLC Media Player volume more than 100%. I come across this statement very often.

I actually see Over-amplifying the volume as a good feature, especially for laptops where internal speakers are not loud.

A quick Google search on harms of over amplification concentrates only on the distortion of sound. I could see no reported harms in hard-wares.

Help me conclude this.

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too many variables, it depends on the source of the audio, some movies I play need to be boosted well above 100% in VLC to hear them. –  Moab Oct 13 '12 at 15:39
    
(On my pc at least) 100% volume in VLC is equal to 25% volume in Windows. You can see this if you click on the sound icon. This will show you the volume of your programs in real time. –  Simon Verbeke Oct 17 '12 at 8:00
    
My speakers broke after having set the amplification to 150% during 10 minutes. But the original source of the problem was that the laptop has been standing on the couch during the night, so it was already hot. I'm pretty sure it is a question of temperature and of component quality. –  leye0 Nov 24 '13 at 15:07

4 Answers 4

up vote 4 down vote accepted

I believe the only thing that will happen when you raise the volume above 100% is that you will get clipped, distorted audio.

You should not be able to hurt your speakers unless you are using an amplifier that is rated above what the speakers are. So if you use a 100W stereo with speakers rated 20W, you can blow them.

In a laptop, the internal amplifier has been selected by the manufacturer and should always work with those speakers which are also manufacturer selected. I can see some really cheap or low quality laptops possibly being susceptible to defects here, but it's pretty unlikely.

Sound cards don't contain amplifiers - that's why you have use powered speakers with them. On a laptop, they've included "powered speakers" for you, so to speak. So I don't think there's a way for an application program to increase the wattage the internal amplifier draws and then cause your speakers to break.

Although come to think of it, they do have "pre-amps" to bring things to "line level..." but I'd have to defer to an audio expert on that ...

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Software amplifiers don't work the way that electronic amplifiers do. There's no actual electroncal/analog signal to be amplified. Instead, what is being amplified are the digital channels in the your audio stream.

So your speakers are already preset to output a particular decibel range in response to audio channel data. That decibel range is determined by the hardware specs of your speakers and the volume settings. Therefore, along its output range of frequencies, it can only achieve X decibels of output no matter what input it receives. VLC Media player, FFdshow, or any other audio filters are unable to change this fact

So from the perspective of a software audio amplifier, all you can do is manipulate the sound channel to increase the perceptual or relative loudness of the audio channel within the fixed range determined by your hardware.

There are a few ways to do this:

  • Adjusting the levels of the audio channel, much like an equalizer (a set of volume knobs for different frequencies that adjust the amplitude of that frequency(range)):
    • The most basic way of doing this is cranking each frequency range's amplitude all the way up. You end up with a pretty flat frequency response and less-than-high-quality audio, but it increase the loudness of the audio channel compared to more reasonable/suitable equalizer settings.
    • You can also use an equalizer setting that accentuates certain frequencies to the max while toning down other frequencies. You can get less of a boost this way, but it will usually sound better.
  • Adjusting the dynamic range of the audio

    • This is a legitimate technique that's unfortunately been abused in the past couple decades by music producers engaged in the loudness wars in the quest of producing a "louder" sound. Its basis is in the fact that audio formats have a fixed decibel range, e.g. CDs are governed by the redbook standard, which specifies how audio data is encoded onto the disc, as well as how playback devices should interpret the audio data, thus setting hard limits on how loud a CD can be.

      However, the red book standard, like most modern multimedia formats, actually provides a very wide dynamic range to allow for hi-fi playback of music. It's capable of representing very quiet sounds, as well as extremely loud sounds, giving content producers the freedom of this huge dynamic range to play with.

      Unfortunately, record producers discovered they could compress the dynamic range of their recordings (which naturally ranged from quiet to moderately loud to very loud notes) to just the upper part of the dynamic range scale, and their songs would blare out on playback devices much louder than they were actually recorded. This had the effect of making their artists seem more raw, exciting and "extreme", whilst making their competitor's albums seem tame and muted in comparison when they played much quieter on the same volume settings.

    • Well, your computer software can do the exact same thing. And it's actually a fairly common practice to do this when playing back DVDs, which are often mastered for the hi fidelity playback equipment of high end home theatres, causing the home PC or laptop playback experience to be less than ideal (gunshots and explosions being too loud, while dialog is too quiet).

    Now, there are ways to do dynamic range compression that only increases the relative loudness of the audio, without undermining perceptual quality. However, if you over-compress the dynamic range, you will start to introduce audible distortions in the audio.

And then there are of course more advanced techniques that combine these basic methods with more intelligent algorithms and more novel manipulations that can "boost" the sound without deteriorating the quality. For instance, if you can over-compress the dynamic range of the audio while digitally compensating for the distortions it naturally creates, you can make the audio even louder while maintaining an acceptable level of quality. Supplementing the original bass signal using other frequencies can also produce a "louder" listening experience, without breaking any laws of audio electronics physics. Likewise, a smart algorithm might be able to pick out the sounds that audiences are interested in (dialog, music, central sound effects, etc. while muting noise or less important audio components).

long story short, there are myriad ways of amplifying the playback audio on your computer. Some are certainly more effective than others (VLC does a much better job than most filters), but there's no way it could itself damage your speakers unless your speakers were poorly designed or defective in the first place, since all they're doing is manipulating the audio channel to output it at the upper end of your speaker's natural output range.

Now, having your speakers blaring at 100% all the time may wear it out much sooner than playback at more reasonable levels, but that really has nothing to do with software volume amplification.

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A lot of good points in here, but also some unprecise or even incorrect information. 1. You're talking about a graphic equaliser; in any properly designed model cranking all bands up will be equivalent to just setting the gain to more than +0dB (e.g. more than 100% volume in VLC), which is at any rate preferrable and in fact completely OK if the source material is not already peak-normalised to 0dB. Boosting only some frequency bands can actually bring the loudness up more if done with according use of the Fletcher-Munson curve, but will always degrade (at least change) the quality. –  leftaroundabout Oct 13 '12 at 15:42
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2. Dynamic compression is in itself not merely a cheap trick, it was used well before the redbook standard and not just to bring the volume of recordings up but also because of many other benefits, like making a band's rythm sound "tighter", a singer's voice appear closer etc.; however you're right that it's particularly overused in CD masterings these days. Problematic is not so much traditional compression (which always retains the dynamics to some degree) as digital brickwall peak limiting. –  leftaroundabout Oct 13 '12 at 15:43

There is some potential for damage if you drive the speaker hard enough to cause the cone and/or suspension to rub against the supporting frame. This would come through as a sort of distortion.

You can overheat and burn out a speaker by driving too much current through it.

And any speaker involves components that flex, and the more they flex, the more wear occurs. So the "integral" of all volume over time is effectively a measure of wear.

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Do you think there is a functional volume level that stays beneath the threshold for wear? On my last speaker system, I usually kept the volume below the recommended notch, and after 10 years when the system finally gave out, it didn't seem like there was any appreciable damage to the speakers, just some component in the amp that caused even the max volume setting to be pretty much inaudible. –  Lèse majesté Oct 20 '12 at 22:23
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@Lèsemajesté - I doubt that you can get things down to zero wear, but likely wear increases non-linearly with volume. Keep in mind that a speaker will go bad just sitting there, doing nothing, as the cone slowly deteriorates with age and the glue holding things together "creeps". (In the past I've "repaired" a few old, failing speakers by simply turning them upside down so that gravity pulls the cone in the opposite direction. But these were large 12-16" speakers.) –  Daniel R Hicks Oct 21 '12 at 2:59

Over-amplification means a lot more current flows into the speakers to produce the sound.
If you really want sound, you could connect the audio out to speakers or headphones for a sound level that is audible but not harmful to your machine.
Higher impedance of external speakers means it'll draw a lot of current. So check which one will suit your laptop. Hope this helps.

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for a sound level that is audible but not harmful to your machine My question still stands regardless of the speakers either internal or external. –  Lakshminarayanan Guptha Oct 13 '12 at 11:51

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