Convert iPod Volume from Percent to dB, How to

sue4 wrote:
... I wonder how can I measure the volume from percent to dB, without additional tools?

You cannot.
I will attempt to explain this without technical expressions (where possible).

When discussing iPods, the dB (or Decibel) is the unit of measurement used when measuring how loud the sound is that is reaching your ears. In other words, how much pressure the sound puts _on your ears._ Since this can change, simply by changing headphones, then displaying the dB output on the iPod would not be accurate, because it would be measuring the electrical level in the iPod and not the pressure on your ears. The dB levels you have seen are referring to the pressure on your ears. This is also known as dB SPL (sound pressure level).

To take a dB reading of an iPod, you would need to place a dB meter close to the headphones (yes, this a simple explanation) and the "microphone" in the meter would measure the sound pressure level and give you a dB reading. So you would need extra equipment to take your own readings and even then, unless you understood exactly how to do this, you could get false (and incorrect) readings.

(The volume display on the iPod is shown as a percentage of the maximum output the iPod can achieve, but it cannot tell you how much is reaching your ears.)

So, how many decibels (dB) is safe? As you have probably found from your research, 80-85dB is loud, but providing you avoid prolonged exposure, you should be okay. Note that no-one actually says how long "prolonged" is. However, almost everyone seems to regard 100dB as far too loud and that you should not expose yourself to this level for more than a short time - one web site says two hours and another says 15 minutes! That's a big difference!

Finally, your comment on European Union iPods. You are correct, all iPods (and all other makes of mp3 player) sold within the European Union (EU) countries have lower volume output than those sold in the rest of the world. This is because the EU has decided that we should be protected from ourselves. However, even with this limit, it may still be possible for someone to damage their hearing.

Phil

Interestingly, it turns out that it is not true that the EU currently caps volume on all music players. At the end of September '09, there were a slew of articles ( Here is one) about the EU discussing instituting a volume cap on all music players sold under their jurisdiction. Apparently, France is the only country to date to institute such a measure, and Apple chose to limit all of their players in Europe, not just in France (from the MSNBC article):


Apple has already moved in recent years to upgrade software and iPods to limit volume levels after France passed a law capping sound to 100 decibels for music players.


You can Google "EU volume limit" on the Google News page and find the articles pertaining to this. It's interesting that over the past couple of years there have been many posts here (I am guilty of such posts myself) stating that the EU had capped the volume.

This is somewhat of an oversimplification of a complex problem. Jeff Bryan and others here from EU countries can explain it better than I can but apparently given the intricacies of the EU when France instituted this limit on MP3 players it in effect became an EU cap. If you do further searches you will find that they are now considering expanding the cap to other devices (including phones) and lowering it from 100db to 80db.

In essence the claims here that it is an EU cap are true. Even if it was just France it would be smart on Apple's part to institute the cap on all European iPods.

Yes, I've read various articles that seem to contradict one another. Some say the EU is considering mandating a cap at 80dB (the French cap is 100dB), others are saying that a removable cap be defaulted to 80dB (essentially using something like the current volume limiter set to something less than maximum), while other articles claim they are talking about requiring a warning.

I do not pretend to understand the intricacies of the EU, just as I am at a loss about some FCC or FTC regulations here. I just find it interesting that the governing body of the EU is just now "catching up" with one of its member nations. I also find it interesting that with the number of complaints we read here about low volume issues, the EU is seeking to decrease the max volume even more than the French have required.

As I said, the members here from Europe do a better job at it, but apparently a regulation on commercial products created by one member (in this case France) extends to all other members through the EU so it is not necessarily a question of catching up. In comparison understanding FCC or FTC regulations is simple.

Now, that's the rub. I've read that changing headphones can alter the SPL by as much as 9dB (assuming a 100dB cap). I would guess that they will use (and Apple has used) an accepted reference to measure SPL (perhaps measuring SPL based on the most sensitive headphones available).

sue4 wrote:
... how can EU set iPod's volume to match with their regulations only by limiting the percentage?

I live within the EU and so I can assure you that "The EU" is a bureaucracy. When have you ever known a bureaucracy to get things right?

... how can Apple be sure that the percentage limit they set in iPods will produce sound no more than 100 dB (for example)?

Although the regulations have been set, and Apple are following them, it doesn't mean that everything is perfect, accurate or even that the regulation is doing the job that was intended. However, to be fair to the EU bureaucrats, their intention has been to protect EU citizens from hearing damage caused by portable audio devices. Have they succeeded? Who knows? But since you are in Asia, you manage to escape the effects of this. (By the way, 100dB is regarded by all sources as far too loud for prolonged listening.)

Note what GLNHP has quoted:

changing headphones can alter the SPL by as much as 9dB.

This adds further to my suggestion that the (EU) regulation is not accurate in it's execution.

In the end, what are you trying to achieve? If you are worried about damaging your hearing because you have an iPod that can produce more volume than mine (here in the UK), then you could use the "volume limit" on the Settings menu of your iPod to set a maximum that you cannot accidentally exceed.

Or, (in a lighter vein) you could offer to swap your iPod with an EU model, but stand back from the flood of EU citizens queueing up to be the lucky recipient! 😉

Phil

i'v had to get a headphone amp as the capped EU volume in the classic just isnt anouth to drive my pro4's but the ipod 5.5 i had could drive them ok. oh and if you still want a limited ipod i'll swap for a uncapped one anyday of the week ( on a like for like baises)

cagalindo wrote:
Im wondering if Apple measure the 130db, highest volume, using their Apple earbuds or HEADPHONES. The sound is so much louder when you use ear phones.

Which just goes to prove what I said previously in this thread. Oh, and by the way, where did you get the figure of 130dB? You're the first one to mention that - and I can assure you that you'll find 130dB is unbearable, even for a minute!

The dB scale is not so simple - 100dB is not double 50dB - it's far louder! So 130dB is not "a little bit louder" than 100dB.

Phil

100dB is about what you get at a consert
130dB is what youd get fireing as gun next to you

and this is what they think on hearing damage:

* A typical conversation occurs at 60 dB - not loud enough to cause damage.

* A bulldozer that is idling (note that this is idling, not actively bulldozing) is loud enough at 85 dB that it can cause permanent damage after only 1 work day (8 hours).

* When listening to music on earphones at a standard volume level 5, the sound generated reaches a level of 100 dB, loud enough to cause permanent damage after just 15 minutes per day!

* A clap of thunder from a nearby storm (120 dB) or a gunshot (140-190 dB, depending on weapon), can both cause immediate damage.

Message was edited by: bdragon122

Im wondering if Apple measure the 130db, highest volume, using their Apple earbuds or HEADPHONES. The sound is so much louder when you use ear phones.

Anyone know?