Voice volume too quiet when burning DVD w/ Nero

Whenever I burn a DVD w/ Nero 7 Premium and play it on the tv, the speech volume is very quiet and gets drowned out by the music volume. however when i play the movie on my comp there is no problem, and when i play store-bought DVDs in my DVD player there is also no problem. im thinking it may hav sumthin to do w/ the burnt DVD’s incompatibility with 5.1 speakers (which is wat my TV has, but my comp does not). any tips?