i actually tried the bog audio offset module first before any others (with scale turned all the way up) and found that i unfortunately needed to use 2-3 of them in a row to get the line level devices up to useable volumes. bog offset uses 10% cpu each and is mono, but i found later (with the cpu database dan made) the airwindows bitshiftgain uses 7% and can get REALLY loud and provides stereo. aw purestgain still goes pretty loud uses 11% and gives more detailed control over volume where bitshiftgain only does volume in steps