Over the years I've bought a lot of music either in physical form or digital downloads. I've never really noticed any quality differences among mp3s I've bought from various sources until recently when I started buying better quality source and IEMs. I literally could care less about the bit...

I've bought all but one of the Van Helen 2015 remasters (Women and Children First only one left to get).  They sound amazing.  They are a little louder than the 2000 remasters and they have better instrument separation.  You really can make each instrument out and Dave's vocals are very clear...

I just purchased some Dunu Titan 1 iem's and the package included s,m , and l ear tips.  I've found medium fits me best, but now which medium is best?  Some have larger diameters than others and then some are red/black in color.  I'm not sure what the differences are or if the diameter size...