Partners, equal, you have the right to have some great speakers, make that plain and to the point of not in contention. Then offer to let her help you pick them out, emphasis on help. If she refuses to work this out then you are already on a slippery slope.
I learned the hard, very very hard way, give to much, lose all respect, suffer through the years, end up being very unhappily single and broken hearted.
Next partner, I simply said I am living part of my dream now, racing cars, building them as well and I will change that when I am ready. I also treated her with full respect, took breaks away from my interests and learned to enjoy hers as well. Now more into her hobbies that I was even into mine but it was my choice. I am the happiest married man I have ever met and I can have any speakers I want as long as they fit in the space I setup for them, front and center but I still want them to look like something she likes to see.