Projectors where do some get there demos to test

i see many that buy some kind of trailers that have demos to test there systems sound
and i looked at bestbuy and they said just put in a dvd …really come on bestbuy
but the demos i see have alot of trailers …where would you buy a demo dvd ?

Hi @lovemovies, Thank you for this inquiry. Hope this helps! Actually, no need for you to buy DVDs for demos you can watch some demos to test on Youtube.