Ears hurt when listening after changing speakers

I have been selling audio for 45 years and customers have commented through the years about pain, ringing or discomfort in their ears while listening to certain speakers, I experience these same symptoms from  certain types of high frequency drivers or with speakers that would normally be quite listenable but are connected to incompatible equipment or cables. One of my customers is an Otologist so I asked him about your problem, his first question was"Why would someone keep listening to speakers that keep hurting their ears?" I could not answer that question. His advice was to stop listening to the speakers and have your ears checked for some kind of problem or disease, if there is no problem diagnosed then get rid of the speakers before they cause permanent hearing damage. He went on to explain that everyones ears are slightly different and there are even people who have a different physical configuration in each one of their ears. Those physical difference are what allow some people to hear certain frequencies differently than others. 
Through the years we have noticed that some speakers will cause certain materials (glass, metal etc.) to vibrate and/or make noise while other speakers have no affect on those materials at all. The Otologist suggested that a correlation can be drawn between those materials that vibrate at certain frequencies and how different people hear those frequencies differently than other people.
If you are one of those people whose ears react negatively to certain speakers, be forwarded that according to a specialist in hearing, even sort term listening can cause permanent hearing damage.