Some original CD releases (and subsequent rips) were slightly sped up or slowed down due to master clocking errors. A "corrected" version likely refers to pitch correction back to 440 Hz concert pitch or the original master tape speed. Changing the pitch changes the binaural beat frequency; a 10 Hz theta wave slowed by 2% becomes a 9.8 Hz muddled wave.
Most music streaming uses MP3 (320 kbps or lower) or AAC. These are lossy codecs—they discard "inaudible" frequencies to save space. For pop music, the difference is negligible. For Hemi-Sync, it is critical. Hemi-Sync - The Gateway Experience -FLAC- -corrected-l
VERDICT: If you are using The Gateway Experience for genuine consciousness exploration, FLAC is not "audiophile snobbery"—it is functional. Some original CD releases (and subsequent rips) were