Use a scanner to identify tracks that exceed 0dB and apply a negative gain adjustment.

You can use the Converter tool to "apply" ReplayGain to the output file during conversion. 3. Fixing Corrupt or "Broken" Gain

The "FLAC gain fix" typically refers to resolving inconsistent volume levels across a library of FLAC (Free Lossless Audio Codec) files. Because FLAC is a format, you have two primary ways to fix volume issues: metadata-based adjustment (ReplayGain) or destructive normalization (re-encoding). 1. Metadata Fix: ReplayGain (Recommended)