Sound is vibrating the speakers, but it's not the volume that's the issue?

I have an audio recording that is a discussion between me and a friend of mine, the sound seems to blow out the speakers at times as if the volume were too loud, but when I reduced the volume by half, I was still having the same problem. Is there a different issue--pitch or something--that needs to be adjusted? And if so, how can I adjust it (preferably in Audacity)?