I have tinnitus and I am a GIK customer. No, one has not caused the other
Others have already discussed the medical side and lack of real cures for Tinnitus. From an acoustics prospective I find that there are two key factors that I must consider to enjoy my 2 channel and HT listening. Low volume and acoustical treatments for music/dialog clarity.
Low Volume:
With my tinnitus I really cannot listen to my HT or music at loud levels without paying the price later with increased tinnitus symptoms. Therefore, I have taken measures to sound proof my dedicated listening room as much as (economically) possible. In this way I can eliminate as much of the non-music and sound as possible in my home and then listen to my music/movies at a lower volume. I don't want my music/movie watching to have to compete with other sounds in the home and thus cause me to increase the volume to compensate.
1. My listening room is in the basement of my home. 3 of the walls are below ground cinder block. This virtually eliminates street noise and most of the noise from elsewhere in my home. I have added a layer of greenglue subfloor on the main level in the floor above my basement. I have solid core doors in the two doors leading to my listening room. Not a room in a room, but enough to lower the transmission of noise into my listening room. I can listen at lower levels and enjoy my music.
2. Audyssey Dynamic EQ. Dynamic EQ is a system that creates a more "perceived" natural tonal balance for lower level listening. For HT it boosts the surround channels, but it also balances the bass which has a more dramatic fall off when listening at lower volume levels. The Dynamic EQ allows me to enjoy a more natural perceived balanced even at lower listening tinnitus friendly levels.
Acoustical Treatments (GIK! plus DIY):
I have spent alot of attention to acoustical treatments in my listening room. The goal is to provide bass trapping so that I can smooth out the bass response and for the higher frequencies eliminate echo, combing, first reflection issues that may smear the sound and make the accuracy of the sound less than perfect. With my tinnitus I find any extraneous noise or reflections compete with the tone I hear in my ears from the tinnitus and make understanding (clarity) of the music that much worse.
3. Bass trapping. The basement has cinder block walls and cement floor. This is not great for bass causing unpleasant peaks and nulls. I have DIY ethan winer panel traps and rigid fiberglass panels in the corners. Also the greenglue floor above acts as a significant bass trap. Key is to evening out the response so that the modal bass peaks do not overwhelm the bass in the room and again cause you to increase the volume to compensate or have loud unnatural peaks that will aggravate the tinnitus.
4. First reflection and corner treatments. Especially for the center channel, you need to absorb the reflections coming from the corners (tri-corners and floor-wall, ceiling wall corners, etc). I find with my tinnitus that any extra background noise or reflections makes dialog in movies that much harder to understand. This also allows me to lower the volume of the movie and still be able to understand the dialog. I have first reflection (center speaker) absorbers as well as (now out of business) eighthnerve corner treatments.
5. Diffusion. I have several GIK QRD and Gridfusor panels in my room. With items 3 and 4 above I have created somewhat of a dead sounding room. I needed to selectively add back controlled diffusion, especially for my front left and right speakers to make the music sound live in my room. I have Magnepan 1.6QR front speakers which are a dipole speaker with a figure 8 pattern of sound coming from the front and back of the speakers. The do not excite side wall or much in the way of floor or ceiling reflections. I have GIK diffusion panel treatments behind the speakers (front wall?) as well as on the back of my room (rear wall?) to evenly spread out the sound coming from the front and back of the magnepan panel speakers.
I find that ironically even tho the tinnitus is a hearing related syndrome, it is my audio hobby that has provided a significant source of relief via recreational listening. When I am in my listening room, my tinnitus is much less of a annoyance.
best of luck