Replacing high frequency tweeter horn in my bass cab with a 4" regular speaker with good upper frequency reproduction - Viable solution?

[Baloney Balderdash]

So I am pondering on replacing the stock 8 Ohm Fostex 25H273 tweeter horn (no idea how many watts it actually is) in my SWR Triad I 4 Ohm 400W bass cab with a small regular 4" speaker with good higher frequency reproduction, though still with a considerably lower roll off frequency than the current horn, like something like at about just past 10kHz, as while I really like having some higher frequency content above 5kHz, I don't really need anything much higher than 10kHz, and I don't like the way my current horn reacts to the higher frequencies of a distorted signal.

I would think the mointing hole for the Fostex Tweeter in the Triad I cab could relatively easily be modded to fir a 4" regular speaker instead.

Not to give you all the information I have on the Triad I cab, it is as said a 4 Ohm 400W bass cab, equipped with a 15" speaker unit that recieves the full frequency content of the signal it is fed with, then an internal crossover filter sees to that the 10" speaker unit in the cab only gets the frequency content of the fed signal that is between 100Hz and up to 5kHz, and then the high frequency speaker will get any frequency content of the fed signal that is above 5kHz, but with a build in attenuator that allows you to adjust the level of the part of the signal above 5kHz that the tweeter actually receives, and thereby the level of the tweeter and the treble of the cab. 

However I don't think my problem is the current tweeter being too loud, cause I like that way it is set with the attenuator now on my clean tone, however I seriously dislike how it at the same setting reacts with distortion (it kind of sounds like the horn it self overdrives, even if definitely not blown as it sounds perfect with clean tone however you set the attenuator, and you can hear a clear different in the treble content of the signal as you turn it up), and was thinking a speaker that is less sensitive to the highest frequency content area above 5kHz, as said maybe something that begins to roll off at about just past 10kHz or so, would solve this, and make for a better balanced distorted tone, while still reproducing enough high frequency content to make the clean tone sound the way I like it. 

I want to do as few modifications to the cab as possible, preferably just modding the mounting hole for the stock Fostex tweeter horn perfect for fitting something like a 4" regular speaker unit in it instead, seems to be pretty close to somewhat similar measurements/dimensions already.

 

I was thinking something like the Eminence Alpha 4-8, which is a 4" 110W 8 Ohm speaker that has a fairly broad frequency range, but doesn't start to roll off seriously before about just past 10kHz, rated usable frequency range says 105 - 12000 Hz.

The question is would that work for my purpose, would 110W be sufficient power for driving everything above 5kHz of a signal that should be able to handle up to 400W overall, would the stock 5kHz crossover of the cabinet make sense, even if I realize I will miss out on a lot of the speakers full potential frequency range, would the reflex box or whatever you call that (really not familiar with the correct term, but I mean the internal enclosure for that particular unit in the cabinet) made for the tweeter in the Triad I cabinet being of a fitting size for this speaker, used the way I plan it to be used, or are there any other obvious reasons why this wouldn't work, work poorly, or why it even might work perfectly great the way I have it imagined?

 

Here's the link to the speaker in question on Eminence's homepage, with all sort of information, including a frequency response curve: https://www.eminence.com/speakers/speaker-detail/?model=Alpha_4_8

(I know the link says speaker pair, but I can get a single unit of those here: https://www.thomann.de/dk/eminence_alpha_4a.htm)

 

Other suggestions on how to possibly solve this issue is very welcome, but I just really like the idea of relatively few modifications, and a small regular speaker replacing the tweeter horn, so preferably a solution where that would be the case, without messing with the cabs internal crossover filter either.

 

Here's the frequency response charge from the Eminence Alpha 4-8 speaker:

 

 

And here's how my cab looks (not my paticular one, but a better overlook picture of a SWR Triad I cab from Google):

 

Also I should stress that I actually otherwise really like the tone this cab reproduces.

 

 

Edited June 18, 2020 by Baloney Balderdash