concerts dvds sound really bad?


y have a amp and pre rowland and jm lab mezzos and cd player electro emc1 and a dvd player toshiba 3107.y bought many concerts dvds and in 2 channels doesnt sound good and very low.the toshiba is old ,but do you think that if y y buy the denon 2900 or similar the dvds will sound really better.
alesantin