Yeah, I have to agree with Jeff's summary too...
Volume, pitch, consistency, etc... all contribute to the "severity" of one's T, but now as I consider it, those are not the key contributors of how severe one's T is. It is how severely T negatively affects one's quality of life, that is the standard of measure.
Anyone who has read some of my earlier posts or 'Profile' knows that I have had tinnitus for 58 years, three jumps up from initial volume level, and hyperacusis since 2006 (c/o meds). The 'severity' of each of those transitions was always 'severe' at the time, as I freaked out, went through the usual angst and anguish thinking my life was over, etc. - though as a kid it was a helluva lot easier to get over but in my own 'kid way' it bothered me a lot for a couple of years.
In the first two instances I habituated fairly rapidly and lived a normal life so to speak, though protected against loud sounds after stage II (1980) as an adult. My quality of life after two or three years did not change much compared to before. No-one except my immediate family noticed that I was slightly 'handicapped' so to speak. Some perceptive friends asked why I seemed to sneak over to quieter parts of some event, so they got to know. Basically, the pretty loud internal ringing in my head did not have that much impact on the external life I could live. Thus, my tinnitus was almost a non issue and I only thought about it when, and in, situations of loud noise, or about to partake in them. No biggie. It was a 1-2% issue...So many other fellow humans in much worse shape! Life was good.
Then along came stage III (2006) and the new sister act/brother act of Hyperacusis...This is the > please insert strongest swear word of your choice here < that in my opinion gives the most trouble! Even with tinnitus volume through the roof, it is MUCH, MUCH HARDER to adapt and habituate when hyepracusis joins the equation! It radically affects 'quality of life' and keeps the whole tinnitus anxiety spectrum amped up on over-drive. It took me three times as long to 'adequately habituate' to the even louder tinnitus than I think it would have without the hyperacusis involved. Six years! And even then I had to be much, much, much more careful around sound in general.
This point, about Hyperacusis mixed in with Tinnitus, I respectfully think is not as fully explained, defined, addressed, appreciated perhaps, even on this site, than it I feel it could be. Tinnitus alone, versus Tinntitus + Hyperacusis are sort of two different animals. The tactics for dealing with getting that goal of: 'quality of life' back are similar, but also have significant differences. (Mmmmmmmmm....Maybe I should write a different post on that actually).
I suspect that a majority of people on this Forum, and with T, do not have hyperacusis. Or that is dissipates quickly so does not affect the recovery phase as much. Which is great of course! I mean look at how many people three to six months after coming onto this site in a full blown panic, with new T, are saying goodbye and that life is OK again, and they are moving on. This is what I'm calling 'normal' T. And it's what a lot of the conventional treatments/advice deal with...mostly successfully. People get their lives back. Hence the definition of "severe" gets downgraded from that traumatic, initial: "my life is over!", etc. to: "I can live with this. Things could be much worse!".
So, that definition of "severe", and the absolutely correct aspect of how it affects quality of life, has a big temporal (time) component. Is quality of life affected for a few months? A year? A few years? Forever? There's the rub.
If it's fairly short lived - as horrible as that can be!, then it can even enhance life in some ways by giving an appreciation of what it means to be 'handicapped'. We can gain some compassion and insight into those struggling with physical or health difficulties.
If quality of life is affected 'long term', then it becomes a very different story. And T with H can do that! Or a darn good job of it.
To sum up...Tinnitus IMHO is not that hard to adapt to, eventually. Well, with almost anything but extremely high volumes (and I have that). But add in Hyperacusis, and "severe" almost automatically becomes a part of the condition. After my stage III jump up (when the hyperacusis appeared for the first time), it was only when the hyperacusis died down enough that I could 'adapt' to the tinnitus!
My rough calculation was, that the H eased off about 5% to 10% per year, whilst the T volume stayed exactly the same = loud as hell. So after 6 years, I finally started to get my 'quality of life back' (see "Gangnam Style" video in Positivity Thread, etc.), not because of the change in tinnitus volume, but because of the change in the Hyperacusis!
Well this post is long enough, but I think it is an under-appreciated point and I hope I have shed a little light on it. To those of you with hyperacusis along with your T...please realize that you may have to judge your progress in different terms than those with T alone. Don't feel like you have to meet any expectations, or achieve any milestones, or respond to treatments in similar fashion or similar time-frames.
In particular, this whole thing about not "over-protecting" as it will hold back your progress, etc. Watch out for this one! Yeah it will probably slow it down if you do, but people (even experts/audiologists/whatever) who have not experienced hyperacusis personally, I suspect do not understand this subtle difference and how much more delicately one has to approach the future.
Time, progress, the yardsticks to get back that "quality of life" can be much more challenging and elusive. As some wise person somewhere said: "It's exactly the same, but just different"....Unfortunately, I have had far too much practice and experience of this.
Best to all, Zimichael