The in-line resistor cuts the sound pressure level of the tweeter down. But it also affects the cross-over frequency and maybe even the Q. It also affects the impedance the amp sees. The first two reasons are why I didn't want to start messing with in-line resistors.
Michael, I'd suggest, if you already have not done so, setting up the M80Ti and the M80v4 in the same room and then compare. But I won't make the suggestion because hey...if you like the M80Ti, then just enjoy them. Same with Kodiak and his M60Ti but dude, get a sealed sub. You'll enjoy life a lot more.
But...if you get tempted Michael...and I am not saying you should :), listen but not only to the quality of the sound coming out of the tweeters but also the imaging between the two versions. The imaging is largely the responsibility of the tweeter and the upper mid-range. Really listen to where the performers are situated and what sort of soundstage they form. Listen at lower volumes and higher volumes. I am assuming you have them set up so they will form a soundstage. Some people can't do that or don't know they should or just don't care. Make notes. Create some doodles of the soundstage and where instruments and voices are spatially located on that soundstage.
I remember you saying a couple of years ago you are not an audiophile and you can't really describe what you hear. That's exactly what my buddies were saying years ago. Now my buddies know - they really know - what they are listening to and it's not just bass, mids and treble.
But I also regret their awakening. They were happy with the fuzzy music playing in the background but then they started asking a lot of questions when they came over. What was I to do? I supplied answers and showed them a few things.
Finally, don't swap out tweeters or cross-overs on your M80Ti. Just enjoy them. Axiom has improved all the drivers including the standard ones and the cabinet. Those improvements do affect the curves and the curves represent the system response of the speaker. That system is cabinet, stuffing, cross-over and drivers. So if you change the tweeters or the tweeters and the cross-over, who the heck knows what kind of audio you'll get. It won't be something that Axiom has engineered as a unified system!
