alxSetChannelVolume problem

When I call changeLevelSoundVolume(), I get alxSetChannelVolume: channel '144' out of range [0, 32]. Now where the heck did it get '144' from?

in my common/gamescripts/audio.cs

$levelSound = 6;
new AudioDescription(AudioChannel6)
{
   volume = 1.0;
   isLooping = false;
   is3D = false;
   type = $levelSound;
};

in game/gamescripts/audioDatablocks.cs

new AudioDescription(levelStartSound) {
   volume = 1;
   isLooping= false;
   is3D = false;
   type = $levelSound;
};

function changeLevelSoundVolume(%volume) {
   echo ("changeLevelSound: "@%volume);
   if(%volume>=0&&%volume<=1) {
      alxSetChannelVolume($levelSound, %volume);
   }
}

Help appreciated, dil se.