I have been using "Irrational But Efficacious" ever since Charlie Hanson introduced it and like it very much. I use track 7 about once a month - it really does work. I also use track 4 on 'repeat' to help break in a new component, cable or contact enhancer (quicksilver gold). The CD is also useful to help warm up the system quickly once the amp is turned on. When using track 7, I usually leave the room because certain frequencies will make my head hurt...my cat hates this track! Unlike many system tonics that I own, this is a tweak that I always come back to.