While there is no denying that a speaker with a brighter disposition is going to be more painful at such levels, the reality is that is so loud that even a warm laid back speaker will be unpleasant at such volumes. I hope people don't see this and think we sit around listening at this level and they should too, or more to the point, I hope nobody is actually listening at those levels.
I know this comment will fall on deaf ears, but I was for a few years involved with IDBL and IASCA competitions with sponsorship and the whole deal. I won a lot of competitions even placing in the top 20 in nationals more than once, in fact top 10 once. I had access to and listened to car systems capable of SPL levels in excess of 150db's on a routine basis (this was 1999-2001) and at least one system capable of more than 165 db's (at this time the all out record was high 60's to low 170's). I was stupid and often did not use hearing protection when I should, but amazingly walked away with little to no long term hearing damage from what we could tell. I then had an opportunity to participate in some double blind listening tests that involved testing our hearing and discernment for accuracy and was found to have "super" hearing. Basically within a set valued range, I was able to discern differences in frequency, level, and phase to a greater degree than the average population. Now Fast forward, I started to notice some issues so I had my hearing tested every year using a standard and extended battery of tests. I'm losing hearing above 15khz at this point at a faster than average pace, most likely due to my past and this hobby. I am 34 years old and my high frequency hearing above 10khz is closer to that of a 40 year old, and above 15khz is more akin to what they might expect from a 50 year old (Anything that high isn't really standardized and the tests are only so reliable, so take these age comparisons with a grain of salt). The point is, we really need to be careful, reference levels are dangerously loud, but given that they are only for brief bursts, not a big deal. Exceeding those causes the RMS level to now approach long term danger and is really not a good idea. Testing with ear plugs once in a while, probably ok, just straight up listening at +10 DB to reference, EEK! At least try to remember that I'm 34 and already losing some hearing because of that.