Cables, Cables

Lots of stuff going on with cables that can cause a noticible difference depending on cable construction, length, guage, etc as well as how an individual cable interfaces electrically with the amp and speaker. No easy answer to your question, unless........

You forgot to reinstall the jumpers in your speakers when you connected your single runs. You may not have operative tweeters. Wouldn't that be embarrassing? :-)

I can easily believe that inexpensive cable can outperform expensive cable. For example, I bought some expensive well known flat cable with spaced wires and put it work replacing some much less expensive, much more ordinary twisted 14 guage audiophile cable. This flat cable produced a balance tilted towards the highs at the expense of the bottom end of the spectrum. Crystal clear, but just, for me at least, tonally unbalanced. In another set up I relocated some equipment and went from 10ft of 12 guage cable to 40 feet of the same cable. Rolled off the highs and the bass became mushy (probably the same thing because often its the high frequency overtones that make bass seem fast or slow). Its a crap shoot re proper cables unless you understand the specific needs of your system, electrically speaking. Sounds like you made a good connection with the HD cables, lots of other folks have.