track volumes in a mess

i have about 127gb of a mix of alac files and mp3 the problem comes that most of ripped in dBpower in alac then there is a some bought from digital7,spotify,itunes and the last 5 weeks im using amazon mp3 store which is great. The main problem is the alac all seem to lower volume than the mp3 which when turned up a little do sound better but then when an mp3 comes on it blasts the flat out. I am running squeezebox server on a samsung laptop 24/7 on that has nothing else running onit and is only used for that and duet with a samsung gs2/ipad2 and the duet controller as controllers and i have selected smart gain,track gain and album gain but all are still a mile away from each other. is there somesoft where where i drop my collection in and select a the lowest volume track and lower all the others to that. my lowest seems to either older beatles album or bob dylan. i guessing thats better than ramping up the lower the tracks. plus i am finding spotify way louder that most as well, is there any settings in troides spotify plugin that lets me adjust the volume. 

many thanks inadvance i really would like a a page on volume levels on computer music in a near future mag as am sure as we mix formats and various avenues of gathering are music collections together im not going to be the only one to run into this.