Since marriage is about compromises, there may be WAF, but there's also HAF, since you're half of that equation as life partners. The old antiquated ideas of women keeping, maintaining and decorating the household are over, as its a shared experience, if not merely to show the equality of the genders. In such a fair and equal life partnership, there is no such thing as one half of that duo wielding final say-so. It is discussed and agreed upon with respect to each as individuals as part of a team. Convey these ideas, don't cower and express it from her perspective, as in if you were to present such an ultimatum about literally anything else in your shared lives, then take note of her reaction.
All this is said from a divorced man, by the way, so take it with a grain of salt! I rid myself of WAF over 20 years ago and haven't looked back, but I still do believe in marriage between those who share love, life and interests together.
I distinctly remember my ex-wife expressing dislike for the stereo I put in my Toyota Avalon, that it was too loud (I had 2 10" JL Audio DVC subwoofers in a sealed box in the trunk with a 1 ohm stable block amp). She frequently asked to drive it when she went out to clubs with her girlfriends some weekends and before long I would hear the car stereo blocks away! So if you have shared interests, or can somehow get her to appreciate the superior sound and experience of home theater, then you can also win her over to your point of view.