combining 2 types of speaker cable?

So I replaced some very cheap stranded speaker cable with some good high purity solid core, there are a lot of things I like about this new cabling and in particular situations It can deliver a more to true life rendition than the cheap stranded ever could.... but there are some things I dont like like, the bass, while fuller and more realised, is not as tight and has this fluffy quality. likewise the treble, while more accurately detailed, is shrouded in a sort of light fogginess... with very complex music these issues become a real problem.

The solid cable is 2nd hand and well used so I dont have much hope of these issues fixing themselves with time.

Instead of replacing the cable Im considering adding some extra ’’supplementary’’ cable to this, something high quality (im thinking Litz, to not taint solid core sound with stranded) but in relatively low gauge (18-16AWG) to tighten up the sound... maybe even deliver a better sound than either cable could alone?

Anyone ever try this out?