eli5: Why hasn’t the audio quality of “on hold” music improved in decades?
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a) it doesn’t have to and b) it’s actually gotten worse.
TomScott has a pretty good video about it. What it boils down to is that there’s only so much room on a wire for signals but there’s lots of ways of compressing a signal so it takes up less space. Different methods of compression have different tradeoffs.
One of the tradeoffs they use for telephone signals is they can compress it a *lot* but the compression makes things outside of normal speaking ranges sound terrible.
And then that signal reaches a company where it goes into their internal telephone system, which uses another compression. And that might go into a third, fourth, or more different system to end up at the call center, all with their own compressions. Some are better than others, but stacking them on top of each other cannot end well.
And on top of that splitting an amplifying an analog signal is pretty straight forward. Give it more power, connect multiple wires together, and you’ve got an amplified and split signal. But a digital signal? You need processing power for each one, so whatever bottom shelf cheapest possible system they have serving up the hold music has to simultaneously handle all the conversations that are being held as well as play hold music – which mind you is being compressed to hell and back in a way that’s not good for music – for everyone, all at the same time.
So between terrible compression and minimum possible hardware, you end up with truly atrocious sound quality.
sound is compressed when sending it trough telephone network. Compression was designed to work best with human voice
On hold music uses the same phone system as your normal call, but music is different from human voice, so it sounds bad… compared to your hifi spotify playlist
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