I'm a bit 'confused' by the results that you had with MOTOTRBO radios. I've only seen one case where a MOTOTRBO radio was 'overpowered' by background sound, and that was when I tested one by standing about 4 foot in front of a 100 watt siren on a police car. I don't know what the SPL was, but it was high enough that it literally hurt my ears.
Was the problem in hearing the audio from the speaker (or speaker/microphone, if you were using one), or was the background noise 'drowning out' the audio on transmissions?
MOTOTRBO radios are now used at NASCAR races, with appropriate headsets, earpieces, etc. They're that good, if set up properly, in extreme-noise environments.
Here's a link to some audio files of examples of how MOTOTRBO can work in an extreme high-noise environment:
MOTOTRBO Sounds
John Rayfield, Jr. CETma
W0PM
We are looking at purchasing radios to use for our live production events (I'm an audio engineer for a small production company), and we have looked at digital vs. analog, as it's hard to talk on analog radios in the shows we do (with volume ranges anywhere from 100dB to 120dB+ depending on size of show)...we have tried out the MotoTRBO series of radios, as they were advertised to work well for high noise environments, but the volume overpowers the radios and heavily compresses the audio rendering it useless. We will be doing some basic trials next week with a set of P25 radios, but we are interested in seeing if anyone has used P25 radios for concerts or any similar events with high SPL. Can anyone comment on how well P25 filters out ambient noise/music?