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Comment by duderific | Hacker News Reader

Kind of a side topic, but does anyone know what's up with Sirius XM satellite radio? Whenever I listen to that in my wife's car, I find the sound quality to be obnoxiously bad, to the point that I choose to listen to plain old FM if I'm driving her car.

The higher frequencies (hi hats for example) are mushy and sound like they are warbling, and the sound just generally has a lack of depth. What is the explanation for this, or am I just imagining it?

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I notice it too, and it's because the music is extremely low bitrate - usually 48kbps, but sometimes as low as 32. It's HE-AACv2 - not as good as Opus, but close. Its characteristic artifacts include destroying transients, like your hi-hats.

Probably compressing the living daylights out of it. By squashing it down, they flatten the amplitude in the music and things with a lot of transients (by definition, drums) suffer. It results in a lot of fatigue, because the higher the compression the more it turns into white noise, essentially.

Sirius XM might be one of the last to standardize on a reasonable LUFS setting of 12 to 16.

Highly compressed AAC. Answers on Quora say about 48kb/s of bandwidth, so equivalent to about a 96kb/s MP3, which sounds about right.

Bandwidth allocation is per channel, talk only channels are even worse and some words are barely comprehensible.

No, I hear it too and would like to know how it works. I think some stations get more fidelity than others, but it's almost always compressed as you described.

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