what to buy under $500 bi wire spkr cable

JPS Superconductor 10' biwire was found here for $225 in case if OP wants to take an advantage from still existing sale offer.
I disclaim not to have any relationship or interest to that ad.

The metal dome tweeter in these have a resonance shown here right above 20 kHz. A lot of people are sensitive to this. This may be a large contributing factor.

I agree with Tmsorosk, I don't think this is a cable problem. PSB Stratus Gold's are excellent speakers with great low-end extension. From your description of the sound, it seems as if your amp doesn't have a firm enough grip on the speakers.

I would work there, and then mess with cables only when you're close to the sound you're looking for.

Michael

10 ft runs biwire bannana plugs

which kimber would you buy. 10 foot runs biwire bannana plugs