Some questions & comments:
Why would you completely want to remove all sibilance? It is a natural byproduct of certain vocal output and occurs fairly often in "real life". Probably the base-line here should be to set expectations correctly - if the sibilance is accurately recorded in your program material you probably want it accurately reproduced - no?
Next, are your speakers properly set up & calibrated? That's the first thing to attend to. Sibilance reportedly/typically occurs in the 5-10KHz range, so if your speakers are peaking in the upper ranges (including maybe even higher than 10K) that could contribute mightily. That's probably the #1 thing to check out.
Room (reflections, etc.) is probably next. Since your speakers are what makes the sound and the whole room environment (including speaker placement) is the next-most significant thing that affects what sound(s) reach your ears then that's the next place to focus. Little things, like "is there a flat-topped coffee table between you & the speakers?" may contribute significantly to what's reaching your ears in your listening position. You can find a wealth of material on room factors at Rives, etc. that may help.
If you plan on keeping your speakers, etc. then all that stuff above is the stuff that matters most. Cables and power cords and conditioners and all that other "stuff" have such an infinitesimal impact on the sounds you hear, when compared to speakers & room environment & source material, that you can pretty much de-prioritize those things until you have your speakers and room tamed. As usual, JMO & YMMV...
Why would you completely want to remove all sibilance? It is a natural byproduct of certain vocal output and occurs fairly often in "real life". Probably the base-line here should be to set expectations correctly - if the sibilance is accurately recorded in your program material you probably want it accurately reproduced - no?
Next, are your speakers properly set up & calibrated? That's the first thing to attend to. Sibilance reportedly/typically occurs in the 5-10KHz range, so if your speakers are peaking in the upper ranges (including maybe even higher than 10K) that could contribute mightily. That's probably the #1 thing to check out.
Room (reflections, etc.) is probably next. Since your speakers are what makes the sound and the whole room environment (including speaker placement) is the next-most significant thing that affects what sound(s) reach your ears then that's the next place to focus. Little things, like "is there a flat-topped coffee table between you & the speakers?" may contribute significantly to what's reaching your ears in your listening position. You can find a wealth of material on room factors at Rives, etc. that may help.
If you plan on keeping your speakers, etc. then all that stuff above is the stuff that matters most. Cables and power cords and conditioners and all that other "stuff" have such an infinitesimal impact on the sounds you hear, when compared to speakers & room environment & source material, that you can pretty much de-prioritize those things until you have your speakers and room tamed. As usual, JMO & YMMV...