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IMD caused by tinnitus?

scrubb

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So, I've not (yet) had a professional hearing test. But, after years of punk rock, loud guitars, mixing sound in small clubs, and crappy theatrical intercom systems, I'm left with permanent tinnitus and hearing loss. It's my constant reminder of how much fun we had in those days. It manifests primarily in the left ear but has slowly migrated to the right over the years. From what I've been able to determine by playing sine waves in headphones and matching them to my tinnitus, it's about 4,500Hz (not sure if that's a valid methodology). I have also done informal on-line hearing tests and know I have a slump between 3kHz and 5kHz (right around where the tinnitus manifests). Surprisingly my hearing sensitivity goes back up from 4kHz to 10kHz then slowly drops off again with a limit of hearing about 13kHz. I may also have some mild hypercussus in the loss range or slightly lower. Lately I've noticed I have a sensitivity to speakers at about 4.5KHz and often feel like there's distortion in the highs. My question, or hypothesis is; could I be experiencing intermodulation distortion from a combination of the internal tinnitus and external high frequencies? I'm really no expert on hearing or IMD, so maybe it's a dumb question and all the speakers I listen to distort in the highs. Or maybe there's some other phenomenon at play. Now that I think about it, maybe I could test this by using the same sine wave at 4.5kHz and see if I notice distortion.
 
or maybe Dysacusis:

Dysacusis is a hearing impairment characterized by difficulty in processing details of sound due to distortion in frequency or intensity rather than primarily a loss of the ability to perceive sound.[1] The term is sometimes used to describe pain or discomfort due to sound, a condition also known as auditory dysaesthesia.
 
I can relate to this, since my tinnitus started higher frequencies in music now tend to sound “dirty”.
 
Personally I've always had rather sensitive ears, meaning, they audibly distort at higher frequencies (between 1 and 5 kHz, similar to your problem, found out way too late in life tbh) at higher levels, but way earlier than what most people I know. When the music gets loud, they say they're fine, while I'm already experiencing clear ear distortion. It's hard to describe, but it's very much "overdrive". That also sounds like it's spreading to above and below the real frequency heard, and as such could be called IMD.

That only got worse in the army as a young dude, where I experienced a painful hearing trauma that took weeks and months to - not heal - but become bearable at least. During that recovery process I was tested professionally multiple times. The initial hearing loss between 1 and 5 kHz was severe the first weeks. Like 10-20dB. Apparently, the constant ringing (Tinnitus) masked all real sound coming from outside. That range is also where the average human ear is the most sensitive, so all that is no wonder.

It got much better after a while, but until today I retain a slight dip in that range, 4-6dB. Of course my brain has long since adapted, but biological computation and brain plasticity can only do so much. I don't directly perceive a loss, but it's undoubtfully there. And some mild, sometimes annoying Tinnitus of course.

In my experience, the biggest effect of Tinnitus is the masking. Your damaged ears' audio follicles (=sensors) produce a false signal that overlays the real, physical input. It's irreparable "wet sensor damage", so to speak. What I found the last years is that headphones are the devil for your ears. If you want to listen loud, use speakers in a room instead. The overall levels are naturally limited by the physical experience, especially by fat bass that tells you: now it's loud enough - and what you know your neighbours can tolerate. :D

There is no known cure. All you can do is try to adapt and live with it. And take care of your ears at all times.
 
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