I bought a new Acer projector to show movies in family yard. Or least I thought so! Trying to boost sound by running audio cable to boombox while on aux. I tried projector audio in and that didn't work so I tried the audio output to boombox and no luck there. I also have a dvd player hooked up to projector. So far only can see movie or strain to hear it on projector's speaker. Any ideas?