Suggestions on detecting collision? I'm using a Piezo but it keeps picking up false positives from my MP3 player.

Hi all, I'm trying to make a lightsaber. I'm using an accelerometer to detect movement and a piezo to detect collisions. When movement is detected, the MP3 player will play a "swing.mp3" sound. However this noise will occasionally trigger my piezo into thinking that it is a collision.

Does anyone have any suggestions on how to detect collision while filtering out the noise made by my MP3 player? Are there even any sensors which allow for this behavior? Or is there a way to sound-proof my piezo from the speaker to avoid picking it up?