Officially, Rocksmith uses .psarc file formats for its songs. Custom DLC (CDLC) uses the exact same format, tricking the game into thinking fan-made charts are official tracks.
A Rocksmith CDLC pack is typically a curated set of these files bundled together. They come in several forms: rocksmith cdlc pack
Because these are unofficial, they are not available on Steam or the Xbox/PlayStation stores. You must source them from community websites like CustomsForge (the central hub) or via torrent aggregators that compile "mega packs." Officially, Rocksmith uses
Many new players download one song at a time. While functional, this is inefficient. Here is why searching for a Rocksmith CDLC pack is the superior strategy: Because these are unofficial, they are not available
Sometimes you find an amazing CDLC pack, but the audio volume is too low compared to official songs. You can actually fix this.
There are tools (like Rocksmith Toolkit) that allow you to:
Warning: This modifies the file signature, so online leaderboards might reject the score, but for personal enjoyment, it’s a lifesaver.