Easily the best and most significant sonic tweak one could ever make!

Well hearing aids of course (if you need them and many don’t realize they do). I was diagnosed with asymmetrical hearing loss in my right ear over a year ago at only age 52. Entirely in the upper frequency. (As hearing loss per my ENT is almost always symmetrical, the protocol for this unusual diagnosis is a MRI brain scan to rule out a tumor; thank God everything was normal there).

Anyway, while expensive (partially covered by Insurance in most plans in the States), the different listening to music is in absolute terms startling. The proverbial veil is wayyyyy lifted particularly on lyrics but really the whole presentation is improved from the midrange thru to the top registers.

Keep this in mind before upgrading your electronics or speakers and perhaps instead upgrade the most critical precision instrument....your ears! I share this and if it helps one member on here, well that would be really great.
Oticon user for several years. Definitely provides a huge improvement to music enjoyment and life in general. Don't put it off and the concerns about will a hearing aid not provide good sound quality are baseless, at least with my setup. You really can't (and IMHO shouldn't try to ) tune your system to accommodate hearing loss. Modern hearing aids are much more accurate and better for that. Oh, and I wouldn't waste my time with the in the ear canal type. They are a big compromise for vanity. The behind the ear versions work better and are now very small and discrete. Mine have no external controls and automatically adjust to volume and ambient noise levels. They work incredibly well, including for live music. Just do it and don't put it off, you'll be glad you did!
 @agosto .  I had similar concerns about the sound being degraded with hearing aids. It depends on the type used. I use open type with microphone outside ear and tiny tweeters inside canal. The small tweeters do NOT block natural sound. They only fill in some missing higher frequencies. I got mine from Costco for about $2600 and I am very happy with them. My insurance paid for the majority of the cost. I sometimes use a Schiit Loki EQ to boost the highs but I think the hearing aids work a little bit better. Good luck. 
@aj523--Since your hearing is "asymmetrical" (I have exact problem you did--HF loss in right (too much rifle range)) are the aids also tuned asymmetrically ?  If you don't really need one for the left ear do you still have to wear one if you use one in the right ?

Yes, at least in my case, I needed to wear one for the left and they adjust it to match your right. I think it’s an equilibrium thing and will also help preserve your left ear longer if it’s a genetic trait. I have hearing loss in my left ear too but it wasn’t as severe and I could have survived without one had it been symmetrical (meaning the right matched the better hearing in the left). My left hearing for a 51-52 year old male was slightly below the curve.  My right was no bueno! Like over 30 percent loss though they don’t like to use a metric like that to describe it.  that helps.