Volume disparity issue-mobiles vs dispatch

Hi all, new to the forum and hoping I can get help resolving a volume disparity issue with our system at work that the tech guys can’t seem to solve. We use a central dispatcher, hand held radios, and vehicle mounted radios with several repeaters. The problem we are having is this: the volume coming out of the speakers on the hand held radios and vehicle mounted radios is louder for dispatch transmissions than for other hand held and vehicle mounted radio transmissions, significantly louder. Additionally, the volume for other dispatch and hand held/vehicle radio transmissions on other frequencies does not have that same disparity. Also, our dispatch is at the same volume as the other frequencies. In other words, the volume of our dispatch transmissions coming through our hand held and vehicle units is louder than our other hand held and vehicle units’ transmissions. I don’t know anything about our equipment set up but I did take a look at the equipment stack and I noted a Motorolla MTR 2000, a Motorolla MTR 3000, a Harris Microstar, a Raven, and four Avtec units mounted. I did not see any model numbers on the Raven or Avtec units. Our handhelds are Kenwood NX-300 and our vehicle units are a mix of various Kenwood models. Any suggestions would be much appreciated.