It would be nice if there was a way to check the system audio volume via the web audio API. Then you could display a notice only if the volume is too low or too high. Alas, no such functionality currently exists without browser plugins.
I would agree that it would be nice to have an option to check if sound is not muted, but not to actually check the volume.
One of the worst user experiences I have experienced in the recent years is those notifications telling me that my volume is too loud. But such assumption most of the time is totally wrong as it is hardware dependent. Especially when you use additional speakers or headphones with their own volume regulators. On windows 8.1, every time you make your volume higher than 40%, you will be interrupted with notification about high volume causing hearing loss, similar tactics is used in android.
So in my opinion checking system volume to determine whether the sound is too low or too high is completely wrong approach.
it's hardware dependent, but I was ruining my hearing until I realized that in fact I don't need to turn up the volume from those notifications. Ears can work much like eyes do in the dark/quiet and adapt.
I wonder what the potential output volume range for unpowered headphones is for the volume set at, say, 40% in windows.
Well 40% is enough volume for properly hearing what comes out of the headphones speakers. But I'm talking about using headphones with their own volume adjustment or external speakers. If you try to watch a movie on most laptops using their native speakers, you will definitely not going to hear a dialogue at 40%. You will want to make it play louder, but once you try to adjust it you'll be interrupted by this notification.
I understand that people might need to realize that loud volume can damage their hearing, but I'm advocating that arbitrary checking of the system volume is not a proper way to do it.
I have some cheap unpowered Sennheiser headphones, and 20% in Windows is plenty loud enough for gaming. At full volume I can have them sitting on my desk and still hear everything clearly :D
Percent of volume says nothing about the line level, which is hardware specific. Since audio jacks were invented before we had industry standards bodies, there is no specification that hardware manufacturers have to meet. Many provide around 1Vpp, or -10dbV, at max volume, but it's going to vary from device to device. The impedance of the headphones are going to affect the SPL as well, and none of it is likely calibrated to any high degree of certainty unless you're buying professional equipment.
As others have stated, that's not necessarily going to do the trick, either. I'll make a huge leap here and guess that you're a primarily laptop user. Don't forget about desktop users.
I use an external amplifier connected through a front-panel IO port. Both the front panel and my amplifier have volume knobs. I don't use the system try to control my levels. I know I'm an odd case, but surely there many people out there with basic integrated speaker setups with volume knobs.
The simplest solution would be to visually indicate to your user as early as possible that your page uses audio. If it is designed to be particularly loud or quiet, you can mention that, too.
