Ever since the beginning of (consumer) digital audio, there has been an ongoing debate over DAC's, analog vs. digital, etc. The original design intent for CDs has, over the last several years, been almost realized - a quantum leap over the earlier versions of gear designed to retrieve those elusive bits. One thing that I find has been consistently overlooked is the actual data retrieval itself, BEFORE it gets translated via DAC (or even digital cable leading to the DAC). I've encountered many products purporting to be the holy grail of CD restoration/ improvement/ enhancement, but one product has stood out: a CD treatment called Essence of Music. It is a two step process that, in a nutshell, allows the laser to pull out more of the music. This leads to a more accurate reading of the data (improved source quality). I am not an engineer or a scientist, but I do have more than 40 years' experience in audio, and I am stunned by the difference between treated and untreated discs...and so are other audiophiles when they hear it. Over the past few years, I have gone to Rocky Mountain Audio Fests with a huge book of CDs...and I deliberately had two identical discs, purchased from Wal-Mart, Target, or even at the shows themselves. I present an untreated version of the CD, and after 30 - 45 seconds, I ask the exhibitor to exchange the CD, playing the same selection at the same volume. The looks on everyone's faces (including the exhibitors) tells the whole story. Through the years, I have tried other products, and even done the 'green marker' thingie, in an attempt to wrest the last bit of music from those silver discs, but this product is the ONLY one that has consistently delivered the goods, year after year. It is not cheap (what is, in audio these days?), but the difference in sound quality is comparable to upgrading your cables, or amp...you get the idea. I have even purchased 5 or more copies of the same disc, and found that more treatments yielded even better results. The change is apparent even on "low-" or "mid-" fi systems - even playing a CD on a BLU RAY disc player. Try it out - BEFORE upgrading anything else. You may be pleasantly surprised.