Short gap between tracks in multi-movement classical pieces

[rongon]

Update:
With SoX enabled, there's always at least a little gap of silence between tracks. The lower you set the sampling rate, the shorter the duration of the silence between tracks. If I set SoX to resample to 24bit/96kHz the gap is hardly noticeable. If I set SoX to 24bit/384kHz, the gap is very noticeable (longer duration).

Once SoX is disabled, there is no gap at all -- or at least it's so short it isn't audible.