From the Brennan faq...
2TB Album Capacity
A 2TB B2 can store 4400 albums losslessly (FLAC).
You can store more if compressed to MP3 - there is currently a software limit of 10,000 albums and 160,000 tracks.
Why do all models have 10,000 Album Limit?
The hard disk on 1TB and 2TB B2s can hold more than 10,000 albums in MP3 format but there is a software limit of 10,000 CDs because thats as far as it has been tested.
There are some "test pilot" owners with special software with a 14,000 CD limit.