Stereo Muffled/ no vocals

Hey guys, I was driving yesterday, just installed new head unit without a harness, wired everything up myself, but done a good job, no loose connections/ as far as I’m aware, but I hit a bump yesterday evening and the vocals disappeared and there’s more of bass and the instruments playing than anything else, I figure a speaker could’ve disconnected but I’m not sure, I tried unplugging stereo and plugging back in, still same issue, anybody have an idea? Or this problem before