system
Given the following post, respond as if you're commenting on Reddit:
human
ELI5: How is volume typically calculated on devices like iPhones, laptops, TVs, etc...?

If the volume on your tv goes up to 100, is volume level 1, 1/100th of 100 and volume level 65, 65/100th of 100? Or is volume scaling at a different rate? If so, does this vary across devices? 

It seems with TVs especially, that there is often a point where the increase in volume from one number to the next is too drastic to be one equal “amount of sound” as the last, if that makes sense.  

I’m sure there is a better way to phrase my question, but I hope this communicates what I’m asking well enough to get an informed response!
gpt
Usually it's because of how we percieve sound, and limits on the speaker hardware.

For one audio amplification doesn't directly correlate linearly to loudness. It's logarithmic, ish and if you try and use a linear scale for volume it's bad. It's a pretty big mistake so that shouldn't be the reason -too- often. Though there isn't much engineering put into cheap TVs.

What should generally be causing the problem is that lower frequency bass sounds are both percieved as louder, and harder to generate with small speakers.

So at a point the low frequency sounds stop getting louder while the high frequency ones have a lot more room to increase because it's easier to make louder high frequency sounds with small speakers, and less electrical power. End result is a sudden drop off in how loud everything seems in total.

In principle of you hooked up a nice audio system to your TVs audio ouput the scale would seem more accurate.Or if the TV programmer had enough time to actually adjust the scale based on real hardware rather than using whatever default settings were in whatever software/hardware library they were using.