The crossovers in professional speakers don't fail that easily. It could be a blown tweeter. To confirm remove the metal grille-- remove the screws of the Horn Tweeter -- remove the cable connectors on the tweeter terminals ( Red and Black wire ). Now if you have a multimeter put it in Ohms range and touch the probes on the tweeter terminals-- It should show a reading betwwen 4 to 8 Ohms depending what is written on the back of the tweeter magnet. If you do not have a Multimeter you can take an ordinary cell/battery ( 1.5v ) from a TV remote and touch the terminals of the Horn Tweeter with the battery. + to the tweeter + ( a small red dot or mark will be there on the tweeter ) and -- to the tweeter -- . When you touch the terminals or give 1.5 volt supply the tweeter will make a scratching noise.
If you do not hear the scratching noise - it indicates a blown tweeter coil and will need replacement.See link below for spares:- http://legacysoundservice.com/catalog1/product_info.php?products_id=1417
But if it does, you are in trouble and will need professional help from a electronic technician.
Could be blown HF Amplifier, suspect the crossover last. They seldom fail.
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