I too found Sibilance due to the following:
- Source material
- Poor electronics (amp, preamp and or digital source. Never got sibilance from vinyl unless it was on the recording.
- Crossover.
Crossover? Yes. Midfi speakers (not axiom) use electrolytic caps in the crossover, occasionally bypass by a small value mylar cap. Electrolytics simply don't belong in the path of the mid or tweeter. As a woofer choke, OK. These 39 cent caps are 10-20% value, and smear the signal (time). Sibilance is one of the deleterious effects.
Simple proof: I just refurbish four Bose 301 speakers. Bose are the king of thump and sizzle. Most blame the sibilance on the cheap drivers....but that's not the whole story.
When I rebuilt the 301's, I replaced the crossover caps with 5% metallized polypropelene. The result was a much cleaner treble and 90% of the sibilance and grain was ameliorated.
I had some ATC SCM 12 which are ruthlessly revealing. I was getting some sibilance and grain, until I upgraded my then cheap technics cd player to an Arcam Alpha 9. Sibilance was GONE.
A final source of noise might be power. If you live near an industrial park or military base, there is a ton of hash in the power, and even a modest power filter helps.
