There will be natural variations in volume between readers. Reject only if the volume is so high that the recording breaks up, or (more commonly) if it is so low that you can’t hear what is being said without reference to the written text.
Okaýjylaryň arasynda sesiň gatylygy babatda tebigy tapawutlanmalar bolar. Diňe ses şeýle bir ýokary bolup, ýazgy kesilýän bolsa, ýa-da köplenç halatda ses şeýle ýuwaş bolup ýazylan tekste salgylanman aýdylýanlary eşidip bolmaýan bolsa ret ediň.