Thread: Pure Sine Wave buzzing loudly

I've researched many times about power inverters, and found that modified sine wave inverters give out more buzzing through audio, whild pure sine wave gives out none(or less). I used 2 modified power inverters that gave out little buzzing , but I decided to buy a pure sine wave power inverter(wagan brand) which does in fact say "PURE SINE WAVE INVERTER." I try it out in two different vehicles and notice the buzzing is so loud it's almost unbearable to listen to music through a laptop, or other electronics I've tried. In my car(Chevy Lumina) However, I did also notice the buzzing wasn't as loud when the engine was off(I'll say it was actually tolerable). Maybe my battery connection is bad, or the car is old(which same might go for my sister's car, the one I also tried it in) I must say I was rather disappointed with the buzzing noise, but I really don't know for sure what the problem might be. I was hoping someone here might be able to tell me what could be wrong, and any possible solutions. I'd appreciate the help .