I purchased this radio to try the DMR network. When I received and programmed the radio it was working fine, but the next day the speaker started sounding like it was broken. I turned off the radio and when I picked it up again the audio was fine. At this point I believed there was something on the radio software that was causing the issue. I reprogramed it and it continued having the same issue.  During a conversation with KP4EOP and KP4ECC I started playing with the radio and by accident I removed the external mic cover and the audio started sounding better than when I received it for the 1st time…. Apparently the problem is that because the radio is waterproof (sealed) the speaker air compression doesn’t have a way to escape (bad design?).  I’m posting this information in case you encounter the same issue with this model. NOW you know the easy fix!