Aftermarket fuse to tame a bright system?

Ahem...changing the toe-in (or lack thereof) of your speakers can greatly impact treble. Give it a try before lightening the wallet with multi-colored unidirectional fuses.

I definitely agree that you need to get them fully broken in before concluding there is a problem. Several hundred hours. I would only start getting concerned after a couple hundred hours.

What are your components? If they are budget oriented components then they may require warm interconnects… like Cardas to keep the system balanced. 

Feedback - direct from Synergistic research, a fuse is unlikely to resolve my problem.  Best to look at changing interconnects (along with power conditioning/power cables).

I kinda like my speaker positioning, so not keen to change it as it affects imaging/soundstage.

Thanks all.

Speaker placement/toe-in changes that will make a substantial difference can be quite small and may even help with other aspects of performance.  This is the cheapest, and probably the best fix; if it doesn't work out, just undo the "fix."  I don't believe one needs to use the same cabling throughout, so swapping in one or two other cables to see if that is the fix is a good approach too; it will cost you nothing if you kept the old cables.  

The last thing would be spending money (although that can be fun anyway).  Power cord changes probably won't do the trick--good power cords tend to help with dynamics, clarity and sometimes soundstaging, but rarely fix brightness--but, then again, they are not likely to make the sound worse, so that it not so much a gamble.