We use FS-BPs for indoor concerts and the sound can get pretty loud from the stage. Some of the users have said they cannot hear comms properly when using the FSBP units even with the all the volume pots turned to max. is there a way to increase the gain in the FSBP by another 8-10dB
Firstly you may want to look at headsets that provide a good level of isolation from the outside. When using the FreeSpeak system in high noise environments (like stadiums or music concerts) we recommend the use of  Beyer Dynamic DT 790 (double ear) or Sennheiser HMD 280 (double ear) or HMD 281 (single ear) headsets
Yes: There is a setting in the BP menu to turn up the volume and gain another 8-10dB
Go the headset menu 



















Select the option highlighted as NORM and change that to LOUD , this gives an extra 8-10db of volume and turns off the beltpack internal limiter setting

Or select the CUSTOM setting and adjust the bass and treble settings to suit 
See page 114-115 of the FreeSpeak instruction manual (which you can download from the web site) http://www.clearcom.com/upload/download/FreeSpeak_User_Manual.pdf