First of all, understand that if you have actual hearing loss in a certain frequency range you will never get it back. Your brain no longer recognizes those sounds. If you have diminished hearing in a certain frequency range, start to exercise that range by getting hearing aids tuned to your deficiencies. If not, you will eventually lose those frequencies altogether because your brain will no longer recognize them.
Second, the best hearing aids for music are the old technology analog hearing aids, a.k.a. K Amps. These will amplify all the sounds in their entirety. Unfortunately these are harder to find because everyone thinks digital is better. Digital offers many adjustable refinements that work well for speech. But digital does not work well for music in hearing aids. Remember, digital hearing aids take the sounds they receive and convert them into numbers. Then they process the numbers and turn them back into sound; all in that itty bitty device you put in and over your ear. The best hearing aids out there have a maximum upper range of 8 to 10 kz; far less than audiophile standards.
It's only been in the past 5 years or so that hearing aid companies have begun to take music appreciation somewhat seriously. Some have "mucic programs" with features that can be adjusted by knowledgeable audiologists. These are noticeable and worthwhile improvements to music listening, but still not audiophile and probably never will be.
I have had 2 sets of expensive hearing aids; one set before the "music program" era, and one after. I was fortunate to find a very knowledgeable audiologist who understands the details of specifically tuning and adjusting my hearing aids to maximize my music listening experience given the limitations of hearing aids. By the way, my diminished hearing is in the upper ranges.
All of this was a noticable and worthwhile improvement, but I wondered if there was more. So I did some more research and asked some questions. This is what I tried and I like it a lot. I purchased a Schiit Loki "equalizer" and put it in between my Oppo 205 and my Anthem AVM 60. The improvement in sound to my ears now approaches "audiophile". It's not as good as it was 30 years ago, but it has brought back the joy of listening to classical music. The fullness of sound through my Paradigm Studio 100 v2 speakers without the hearing aids is better than when I use the hearing aids.
Three caveots:
1. Diminished hearing is unique to each person. Therefore the solution or improvement will be unique to each person.
2. Audiologists selling hearing aids are just that............salesmen. They make their living by selling you something, even if it is not the best hearing aid for your situation. You must must must try several different manufacturers. You must be allowed to take them home for a few days and try them out. And the audiologist you choose must be capable of going into the "music program" and altering and adjusting the specifics of that program to suit your needs; NOT just switching from one music program to another music program. This is a process. You will visit the audiologist several times before you get the most out of the hearing aids.
3. You won't find useful information on the internet about the specifics of a given hearing aid. All the manufacturers are deliberately vague so you are forced to go visit one of their salesman, who by the way only sells one or two brands of hearing aids. It is not like going to a M. D. where the doctor recommends a medication or treatment that is best for you irregardless of who makes the medication or provides the treatment. That is why you must shop around and test drive several hearing aids.