really bright sounding speaker cables

Agree with the Nordost. I've never found a pair that I could tolerate, but for what you are looking for, they may just do the trick.

I've also had a pair of AudioQuest Dragon (silver). The most spectacular cable I've owned in many regards, such as explosive bass and tremendous resolution. But, I always felt I was sitting in a dentist chair, and was deriving the opposite of happiness when I listened to my system. Chasing the problem all over the place, one day, I switched my former copper loudspeaker cables back into the system, and instantly had music again. Rare and pricey, but if you run across them, you may want to give them a shot.

Try the Kimber Kable 8tc I set up a friend who had a little more bass than one would like in a system. It seemed to tighten the bass and was spot on neutral.

I found the Kimber 8TC to be a bit lean in the bass as well, it has a smooth tone in the mids, you could pick some up and turn them over in a flash if they did not suit you.

Cables are great for "fine tuning" of the system. What you have described is IMHO beyond fine tuning. I would look at your upstream equipment as a source to your problem. If you are set on trying cables, I would suggest the Cable Company as they have an excellent trial program.

I also agree with the Nordost recommendations.