A FLAC gain fix refers to the process of standardizing the perceived loudness of Free Lossless Audio Codec (FLAC) files.
Fixing FLAC file volume involves either non-destructive ReplayGain metadata tagging or destructive, permanent volume adjustment, depending on player support. ReplayGain is recommended for lossless, reversible adjustments, while tools like Audacity, dBpoweramp, and metaflac are used for permanent changes. For more details, visit Audiophile Style . ReplayGain in FLAC - Audio Processing - Audacity Forum
Always write tags so your files are ready for both shuffling and full-album listening.
When applying a FLAC gain fix, always ensure your software utilizes alongside Loudness Normalization.