Every individual digital track made from the Beatles master recordings that were sent to Harmonix to make The Beatles: Rock Band were low-fidelity copies imprinted with static. This was a security measure to assure that The Beatles' music wouldn't be sampled by other artists in the event that the recordings were leaked.

These low-quality copies were used throughout development, and replaced with high-quality versions for production.
Contributed by Pogue-Mahone