If the rest of the system and speakers are mediocre, better cables likely won’t make a notable difference. Probably not worth the investment. With more revealing audio systems, there can be a notable difference.
Over the years I had tried various interconnects, copper, silver over copper, silver in varying lengths too. Eventually over time upgraded all of my interconnect RCA and XLR cables on the main input sources and components with varying degrees of positive improvement. Most notable between preamps-to-amplifiers and CD/DAC-to-preamp. Rewarding in some cases.
Recently, I was surprised to notice a very positive difference swapping out some old mid-grade brand name RCA interconnects with much higher grade pure copper ICs for my FM-Tuner-to-tube-preamplifier. Prior, never thought it would make a difference for FM too. It sure can. All connectors and connections were clean on both cable sets, and (yes, FM tuner). I was not expecting any difference at all. Wow, a notable difference, to a surprising degree. Smoother, extended highs, more bass, fuller sounding, larger sound stage and definitely more engaging - much less irritating. In reverse to check myself and hearing, swapped many times back and forth; re-installed the former cables (and a few other mid grade cables) and it sounded like crap again, harsh, not engaging. Sometimes (not always), interconnects can be a weak link in a given audio system if everything else is up to par.
