Midland GXT1000 poor send clarity

I’ve owned a pair of Midland GXT1000 for over 6 years now. I’ve used them for playing airsoft and running events on 20-120 acre paintball fields the NY Catskills and PA. I would occasionally get complaints from other players about their inability to understand my transmissions and assumed it was terrain or signal interference.

I just discovered it was my Midland radios. They sound ok (perhaps a little low-volume) when I conduct a radio check between my two Midland handsets. But when I transmit to a Motorola, Cobra or Baofeng handset, my voice sounds garbled/crunchy when I speak loudly and faint when I speak in a normal volume. To reiterate: this poor sound quality only occurs when sending FROM my Midlands to other brands. Sending between Midlands sounds ok. Sending from other brands TO the Midlands sounds even better.
• When I talk louder or place my mouth directly above the external mic hole the crunchyness and distortion gets worse
• When I try speeking through an external boom mic or in-cord mic, the poor sound is the same as using the built-in mic
• When I set the Midland on Whisper mode, the sound quality is better (less crunchy) but still is faint compared to other makes
• When I transmit from a Motorola, Cobra or Baofeng to the Midlands my voice sound quality is clear and loud (volume dial on the Midlands set at about 80%)
• Send issues persists whether I use Alkaline or NiMH batteries

Any thoughts on what could be causing my issues? I’m about ready to toss these GXTs because they don’t do the job I need them for: 2-way communication

I discovered that the poor transmission only happens when the radio was set to High Power transmit. On Mid or Low power settings, my voice sounded ‘normal’. I read somewhere that High Power only works properly with the Midland NiMH power packs and not AA batteries.