This usually means that the device playing the music is not turned all the way up.
If the music is playing on a phone, laptop or tablet, make sure that the volume is turned all the way up on both the hardware and the software. (turn your headphones down before you do that)
If it is a DJ-controller/audio-mixer-board, that doesn’t need to be turned all of the way up, but it still does need to be turned up higher than you have it.
Make sure the DJ keeps her Silent Disco headphone volume at no higher than 50%. If she has headphones much higher, then she is going to be setting the controller/mixer/laptop/phone/tablet output volume too soft.
