You are right...you can have same FR for all subs and they all sound different. I've had PSA, SVS, and now Funk Audio subs. I can get same FR from same sub position in REW but yeah they all sound different. Mainly because of different size drivers and ported/sealed differences in my room.It has to be the drivers that are used in the 1400 and 2400, as you said it wasn’t an issue with the 118 right? The drivers in the 2400 (and whatever other model its used in I’m sure) just sounds and articulates different from the Rythmiks, even with nearly identical FRs (and same location) to match them up better. When I had the 2400, it sounded totally different than the Rhythmik FV15HP that I had at the same time, even with FR’s basically identical post Audy or manually EQ’d. Heck, even the Audyssey twerp tone sounds WAY different on the 2400 compared to any other driver I’ve heard, like was mentioned somewhere on this thread as well. I found this to be very interesting. Even the Audy twerp tone on my SI DS4’s and UM22-18’s sound like the Rythmiks, or very close anyway.
One would sure think, like has been mentioned recently by a few, that setup with nearly identical FR’s, that they would sound very similar, but this is so not the case. It may have to be experienced to be believed.