what to buy under $500 bi wire spkr cable

Kimber

Need to know how long a run you need, the price goes up the longer you go.

Anything that is pure copper for starters. You don't want silver in the mix as it can exacerbate the symptoms you describe. If possible get Cardas. You will only find their lower end stuff even used in your price range but familiarize yourself with the line and jump on a good deal. There are other good all copper cables but my experience is limited to just a few. In the low end giant killer category though I can recommend Pheonix Gold. In the high end stretch your budget besides Cardas, I like the Jena cables even the entry level Jena cable is really good.
If you get the Pheonix Golds, You will have money left over to upgrade your CD player. I owned that Jolida once and if you haven't rolled the output tubes in it, do so first thing. Get old stock Mullards, they really made a huge difference in the sound. I am really being quite serious it will change your sound dramatically. Used ones are fine in that function BTW.

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.