What happens to my hearing, over time, if I wear headphones with Crescendo corrections?
I wondered the same thing back in the beginning stages of this quest. But I can tell you now that between myself and all of my clients, so far, nothing happens except your listening pleasure.
I have been using Crescendo through headphones at loud, but comfortable, levels for a solid 13 years now. (Yes, elsewhere I state 10 years. But that’s 10 years with the Crescendo system I now use. Before that were many, many prototypes and experiments.)
That’s 77 dBSPL, every single day, averaging 4 hours per day, for 13 years. And nothing seems to have degraded my hearing any further.
Now that’s all anecdotal information. And even I would still want to be cautious if given something like that. I understand.
So let’s look at some facts. We know that people with normal hearing can listen to sounds at 85 dBSPL for up to 8 hours/day without ill effect. Sound exposure is cumulative, but this has been found as a safe limit.
When you have a severe threshold elevation like 70 dB, that requires greater gains than for lesser elevations, at all presentation levels. But the gain correction for that threshold elevation when the program material has a level of 77 dBSPL, is a boost of 6 dB, making what your ear is exposed to become 83 dBSPL. That’s within the safe level. Safe duration at that level is longer than 8 hours/day.
Consider further that this degree of impairment probably happens only at high treble frequencies, like 4-8 kHz. There isn’t any music that I can think of that plays 4-8 kHz at a whopping 77 dBSPL. The only thing up there are harmonics of fundamental tones much lower, and even those tones won’t be sustained at 77 dBSPL for very long, if ever.
That means that this 83 dBSPL exposure won’t be for more than less than a second of exposure, perhaps once a day, or once an hour, depending on your musical tastes.
So the cumulative exposure in your most extreme correction channels will be only seconds per day at most. Well below the safe exposure level of more than 8 hours.
Keep in mind, too, that everything we have been talking about here assumes you will be listening at loud but comfortable levels. There is nothing that says you must listen at these levels, and many people choose not to. You can always gain the benefits that come from playing your music loudly, by listening through CLAS, which brings up the faint portions of the music without increasing your volume.
So consider those facts, and our anecdotal experience together, and take comfort in the notion that your hearing will probably remain no worse than it already is.
[PS: I have also performed many dumbass experiments apart from Crescendo, where I exposed my ears to loud sounds in my lab. I tried to minimize the exposure, but I got knocked on my can a few times. And even then, my hearing has not degraded.]
[ PPS: One way to detect degrading hearing, is if you gradually need to keep increasing the vTuning level to keep things sounding correct. An adjustment by a few dB just once wouldn’t indicate a problem. But a gradual increase over time, consistently upward might be worrying.
But my own personal experience has been just the opposite. I started at around 64 dB of vTuning, and found that over time I needed to drop it first to 60 dB, then now at 58 dB. So is my hearing getting better? I doubt it. I’m probably just becoming more discerning.]