LOL, yeah I kind of know about diminishing returns. "Sounds $680 better" has no meaning because sound isn't measured in dollars. You probably meant "the additional marginal utility you get from a marginal increase in expenditures of $680 on tweeters isn't as high as the increase in marginal utility you receive from spending an additional $680 on other goods or services."
Diminish returns is about production (supply side) and diminishing marginal utility is demand side.
LOL, yeah I kind of know about diminishing returns. "Sounds $680 better" has no meaning because sound isn't measured in dollars. You probably meant "the additional marginal utility you get from a marginal increase in expenditures of $680 on tweeters isn't as high as the increase in marginal utility you receive from spending an additional $680 on other goods or services."
Diminish returns is about production (supply side) and diminishing marginal utility is demand side.
It does not appear that you do. This is not complicated. You have two drivers that both render their passbands effectively to an ideal degree, one costs $60 and the other over $700. For me, no further investigation is needed to determine which is the better option. I suppose one could just desire the higher priced tweeter because it costs more, but boy that's pretty shallow.
Take care.