Speaker cutting out at Med/High levels help

I have a pair of ADS M12 that one of the speakers is cutting out the medium and highs sound when I crank up the volume above heavy talking. The speakers then work fine when I lower the volume for a second. They sound wonderfull at lower volumes. They are biamped if that makes a difference.

1) Can this be fixed or do i have to live with this unless I sell them? If so how and How much?
2) Does anyone know the value of these?
$1900 new , a great speaker Used 500-750 pair

Try different wiring options
Clean Tone controls of preamp
Try another pre/amp
Could be faulty crossover ?
Are there any fuses on your speaker lines (in the amp, in the speaker)? If so, it wouldn't hurt to replace them. An iffy fuse could do this.
try swapping some cables around etc. process of elimination. Then you'll know what's breaking up; it might not even be the speaker?
If I had to guess it's possible you have a loose connection somewhere in the speaker, either where the wire connects to the driver or at the crossover. My theory is, as you crank up the volume the vibrations in the cabinet cause an intermittent short. I suspect this could be diagnosed and fixed either by yourself or by a tech for a nominal fee.

Part success! connections cleaned and changed around to much success in sound and imaging quality. Still cutting out to what I believe now is high volume for these speakers but not high volume to me or my nieghbor (Correction both speakers). I guess I must move on to different speakers for higher volume. I love these speakers for low volume sound.

Thank you for your help! Any suggestions to getting higher volume without the cutting out of Mid/highs?

Sub is next and then maggies but I just can't part with these old ADS?