Original
From Youtube
Considering the difference in hertz, I don't see any other reason to blame the problem of low quality.
The problem lies with the user who uploads the video/audio. If he uploads it in bad quality, it will be downloaded in bad quality. I have to say that it is a detail of GG to upload the audio in good quality.
PD: Also highlight the service that is used to download the music, I do not know if I can put examples of this.