Sound source refers to whether the music you play is MP3 or lossless, DVD and CD, etc.

If you are a music enthusiast, you need a power amplifier and an independent sound card. Enthusiasts generally don't need a computer to listen to songs. If they take high-end MP3 or lossless player+in-ear headphones with them, and some take one ear to rest in bed or other resting places, they can also take a home host+desktop amplifier+large headphones.

The sound may be toxic ... be careful with your wallet.