I do transcription work too and used to run into that problem. I
don't know what to tell you, but it sounds like a bug with your
transcription player. I currently don't have a way to adjust the
volume levels of the dictation software player independently of the
volume of JAWS on the system. I do have a separate equalizer with ear
buds that are "noise reducing" and the sound quality is a little
better, but it's painful when the volume level of the dictation is so
low that the only way to hear what's being said is to turn up the
volume on the system, which makes JAWS yell at me. I transcribe with
the typing echo off, but have to adjust the volume to proofread my
work. Different players have different controls. Hopefully, someone
with more expertise can help us both out.