Well... guess I have to jump in the rabbit hole of speaker cables... lol

 I suspect your room is the culprit! There is lots of YouTube info on acoustic treatment. That is the most likely way to solve your problem. 

I have never heard a McIntosh product sound raspy! You don’t have quality cables. I have heard the 10t’s and the 20t’s and thought they were very bright sounding especially the 20t’s. It very well could be a synergy issue. Maybe borrow a friends amp/preamp/integrated to see if the raspy sound follows when changing components

Captbeaver, there seems to be confusion as to what amp you are running with your current gear. You say the Mac 7100 doesn’t have enough power, so what amp are you using when the 10t’s sound raspy.

Also, I see the Mc7100 is 100 watts at 8 ohms. I would think that would work. 10t's are  rated 86db.

In your last thread regarding your system, Georgehifi gives you real good input on your speakers needing current. You may want to reread that.

I wouldn't worry about speaker cables until you get amp situation corrected.

I have no idea what else may be contributing to what you're hearing, but your cables are definitely crap and at least a part of the problem. Speaker cables (and interconnects, and power cords) are not a rabbit hole. They are very straightforward- you try them out, you buy what works. It is only when you try and make sense of why - or worse, try and base your decisions on why - that you plummet headlong into the abyss. So take my advice: don't buy anything you haven't heard in your system, don't even audition anything based on anything other than listening impressions. Buy only what sounds good to you in your system. Stay a million miles away from anything even resembling a measurement. The only three instruments that matter are either side of your head and in-between. 

In fact, not just cables. Stick with this for everything.