Currently using the Klipsch The Fives… But my ears want a bit more…

Are you sure it's more treble you seek? The Fives seem to have a tipped up response already - see measurements here.

Have you tried adjusting speaker placement? For example, if your ears are above tweeter level, try tilting the speakers back so the sound is firing towards your ears. Another thing to adjust is toe-in. Try turning the speaker until you can't see the sides from your listening position. Then start toeing them out in small increments.

Yes, these are already slanted perfectly toward my ears using KANTO TUK speaker stands which worked beautifully.

Full disclosure, I am 60 years old and I do have some high end frequency loss at this point in the game. That’s probably why I need something that’s got a little bit more than what these delivered just to compensate.

My ears are at somewhat of a disadvantage, I am a professional musician by trade, and have had the privilege of producing and mastering about a dozen CDs over the last 20 years. The final process of this was mastering them in Nashville at MasterMix with Henry “Hank“ Williams… So I have sat in front of a $650,000 wall of PMC monitors and heard sounds that very few people will ever experience.

Sounds like you need some EQ. Add some treble, and put a notch in around 2.4 kHz to improve imaging.

Also, since using them with a sub, experiment plugging the rear port.  :)

I would start by playing around with the subwoofer settings (lower the output level a tad then experiment with the crossover frequency if desired).

As you already know, it's all about balance.

DeKay

Great suggestions...I’ll tinker with the EQ on my MacBook Pro as well as the Sub