A FLAC file is only as good as its decoding and amplification. For Jean-Marie Reynaud speakers, the recommended chain is:
Playing the through these speakers creates a synergistic loop. The disc was used to tune the crossovers in the factory. Therefore, when you play the FLAC on original Reynaud gear, you are hearing the sound the designer died for.
Slowly increase the volume while watching the woofer cones. If you see excessive, disordered movement or hear the coil hitting the bottom (backlash), reduce the volume immediately.