Tiberium
Странно. Я как раз читала, что вроде бы не связано. Возможно, дело действительно в моем соединении -- хороший канал к домашнему серверу, а оттуда ко мне, увы, WiFi.

YouTube streams video and audio separately and the web player/app combines them on the fly. Due to this, the audio bitrate is not directly affected by video quality like in the past. Rather, YouTube can stream the video and audio it deems appropriate for a given device and connection. It can also adjust one during playback without affecting the other.

The audio you hear during a YouTube video will usually be 126 kbps AAC in an MP4 container or anywhere from 50-165 kbps Opus in a WebM container. Changing video resolution (360p, 720p, etc) in the video settings will probably not impact the audio stream, but it is likely that your connection performance will.