The Film Machine = inferior audio?

so i really like The Film Machine and would like to continue using it as when it's joined up with CCE SP2 the video quality is phenomenal. however, i can NOT for the life of me achieve decent audio with it. i must have re-encoded the same movie 10 times just testing out different audio settings! if i set the audio bitrate to the recommended 384 kbps, its way too loud and muffled. if i go lower its very soft and flat sounding. ive tried both Aften and Sonic Foundry Soft Encode and the quality has always been very sub-par. oddly enough the simplified ConvertXToDVD has the best audio output in any program ive tried, however i love the ease of use of TFM + CCE.

so can anyone tell me what i should be doing with my audio settings to achieve optimum sound with TFM? what do you use? also, anyone know what type of audio encoding process ConvertXToDVD uses??

thanks in advance for any suggestions