balancing audio levels.

Hi..would someone be able to tell me how to balance the audio levels of different clips.I have tried several ways with unacceptable results so there must be something i am missing. Am working on a project which involves shooting music events as well as separate interviews, many with varying sound levels.I often load multiple clips to the same track of my timeline to avoid cluttering my workspace with large numbers of tracks.The volume slider seems to affect all the clips on a particular track,and volume envelopes seem to do the same also so i have been adjusting the gain for each individual clip.Some of the interviews are not very loud so i "decrease" the gain on the louder clips until they seem about even with each other, by ear.There seems to be no way to "increase" the volume of softer level clips to match louder ones as they all seem to be loaded into the tracks at their max of 0db.All seems well until i render and burn to dvd.When i play the dvd in a regular player i must turn the volume control of the tv to almost full volume to hear at acceptable levels.I know most dvd's have more volume overhead than this. Have even turned up the master volume in Vegas,rendered,and burned again to dvd with same results.I assume the 2 master volume controls in Vegas only affect how i hear it in Vegas and not the finished dvd? Would anyone be able to tell me the best procedure i should follow to alleviate future problems like this? Am relatively new to Sony Vegas6.I also have DVD Architect 3.0 & Acid Music Studio 6.Should i be doing any things there? Help please and many thanks.....