Duh!... Yes, I hear you; captain obvious.
When I replace drivers it is only after significant research and planning (including design and calculations); its why even a "simple" driver change can take several months.
Closed back tweeters are some of the easier projects as various cabinet resonances don't often apply; relatively simple checks of impedance, efficiency and inductance are often sufficient. Although; I have noted that some Seas products (tweeters) often contain peaks and valleys in their characteristics that need to be ironed out in the crossover ; and Seas tweeters, especially, seem to often have a huge peak in the 18kHz range (probably, inaudible to most).
Right now, for some reason, I seem to be in a tweeter replacement period; If it continues I will set up a spread sheet to do many/most of the calculations and highlight potential issues.
My normal procedure is to find a good wide & flat responding tweeter, with efficiency and electrical characteristics that are probably going to be, mostly compatible and switch it in then listen for problems & issues.. It is usually a good enough approach to see me past problem/unacceptable speaker performance (Polk), until they can be replaced.
Poor speaker response is only a temporary issue, IMO.
IF I can bring the Polk 700s performance into line with (or close) to what I want , they also have a somewhat muddy mid-range, I will likely retire the re-built NHT 2.5 towers, currently serving as rear speakers (IMO their maximum power handling is, likely marginal, even though they sound acceptable (better the Klipsches they replaced), (I haven't been able to find mid-ranges for the NHTs that fit and that I am really happy with), and drop these Polks in to the NHT towers' place.
Enjoy!
