When I upgraded my system, over half my cd's sounded terrible (especially rock, etc). The system was so detailed that it wasn't forgiving of poorly recorded cd's. I thought I'd never listen to over half my cd collection. I tried the Auric Illuminator, because if you didn't like the results you can wash it off, and it only cost $39. It worked fairly well. In matter of fact, the treated cd's sounded great in my car's cd player. The Auric Illuminator isn't the perfect solution, but for the price it brought back most of my poorly recorded cd's to a listenable level.
Auric Illuminator, Optrix, others
Recently bought duplicate CDs to try some CD enhancers which have been getting some outragious reviews of significant improvement in sound by improving data read off CD surface. After carefull comparison I must say I prefer untreated CD. The sound is slightly altered with treatments, usually sounding "smoother" however this was accomplished by obscuring fine musical detail, especially treble detail. I want more detail and nuance, not less. I do not have $20,000 plus systems most reviewers have, but my $7,000 system based on Musical Fidelity X-Ray is fully capable of detailed presention. Also magazines perpetuate the notion that there are many CD tweaks (CD mats, blackout pens, surface sprays etc) that you must have to improve sound.....has anyone else done careful comparison with duplicate CDs to study effects of various treatments?