JBL Olmpus speaker system

Try cleaning all the connections inside the speakers. With emphasis on the crossover. You might check the caps in the crossover and replace them. caps and corrosion may be what is the problem.

I have a homebuilt "Olympus" size cabinet using the 375 with potato masher, 075, LE15A, and PR15 passive radiator. I love the 375 and would highly recommend it. You must remember horn systems are ruthlessly revealing and will reflect any upstream imperfections. I have never found the sound hard, although, some amps or tubes have produced a fatiguing glare. This disappears if you match the system properly. I have no glare using system matched 6B4G push pull triodes, 845 and 300B amps. While tubes as small as 45 will run these speakers (I had), personnally I recommend slightly more power for better and more controlled bass. On the 075, I prefer the sound of this tweeter with the crossover on the lowest high frequency gain setting. The thing about this system and other horns I have had, they really shine if you crank up the volume.

Gorg, the Olympus is a wonderful speaker and very well suited to classical music. Linnlp12 is correct about the amplification, you need a good triode SET to get the best from this speaker. Most push/pulls will sound too hot in the mids and solid state shouldn't even be in the same room as your babies! The S8 has the same requirments.

Elizabeth also has a point, you need to check your speakers and make sure that everything is still working fine, after all they're over 40 years old.