Can a great system make a mediocre recording sound good?

Systems that scrape every last detail off of whatever media you have tend to overemphasize higher frequency detail… which ends up being unnaturally harsh and details are highlighted. These systems either just make bad recordings sound bad but also distract from good recordings. This is one of the many balancing acts in building and upgrading your system. A bit more emphasis on musicality and a bit less on detail scraping and you have a system that makes nearly everything sound great. It took me decades to get there, but finally arrived. See my UserID for my system.

Mixed in here is the subjects of what you choose as test music, and what kind of music is critical to choosing a system. The wrong choices and you take your system in places where one kind of music and recordings get better at the expense of all others.

My big mistake was grabbing some electronic music CDs that I really liked. I kept optimizing the ethereal nature (lots of natural treble and ultrasonics (think planar speakers). But most music sounded worse. 
 

Finally, about twenty five years ago I started listening to live acoustic music as frequently as possible… to calibrate my ear. Then the symphony a couple times a month. I then chose acoustic music for auditioning. My ear got trained as to what to listen for and the auditioning then drove very different choices in equipment… making most music sound better at every upgrade.. now if there is a chance for music to sound good… my system will give it. However electronic music sounds natural… not overly ethereal… which I liked… but the result is 98% or the music l listen to sounds simply incredible.

In general… a better system sounds better. The caveat is that there are two ways of pursuing a great system… really detailed or natural. If you pursue ultra detailed, you quickly makes bad recording sound terrible. If you take the approach to have a relaxed natural sounding system, then most recording sound much better… the better your system is the better the recording sounds.