nordic track audiorider U300.....exercise bike

sumerain28

so i recently purached this bike second hand , i have done the 20 minute level 2 weightloss program and it says ive burned about 120 calories ..how accurate would you say this is as when i plug the 20 mins at a moderate pace in on myfitnesspal it says i burned 271cals or there abouts ....also does anyone else have this paticular bike ? mine came with a julienne michaels SD card ...its very very loud and i wonder if there is a way to lower the volume on the speakers??
thanks in advance