When you match the output level of a sub to the main speakers in a system, you do so at a given SPL (75db in the latest Audyssey set-up regimen IIRC). I think the OP may be asking what happens as that SPL changes. Might two different sub models behave differently as SPL rises.
Theoretically, at least, I believe that the the answer should be "yes". In every sub (and speaker, for that matter) some amplifier output is converted to acoustic output and some is lost to heat - thermal compression. The ratio of the two may differer between different designs.
In practical use, I doubt that it's likely to be meaningful (or even audible). Since most dual sub set-ups aren't stereo, the theoretical mismatch wouldn't affect stereo balance (the subs are operating in mono, anyway). The bigger theoretical issue is how thermal compression impacts the combined output of the subs vs the combined output of the main speakers as the SPL increases. This is as true with identical model subs as it is with differing subs.
It may vary case by case, but I've measured the response of my system (with identical twin Rythmik subs) at 75db and at 95db and the difference is negligible. FWIW.
Theoretically, at least, I believe that the the answer should be "yes". In every sub (and speaker, for that matter) some amplifier output is converted to acoustic output and some is lost to heat - thermal compression. The ratio of the two may differer between different designs.
In practical use, I doubt that it's likely to be meaningful (or even audible). Since most dual sub set-ups aren't stereo, the theoretical mismatch wouldn't affect stereo balance (the subs are operating in mono, anyway). The bigger theoretical issue is how thermal compression impacts the combined output of the subs vs the combined output of the main speakers as the SPL increases. This is as true with identical model subs as it is with differing subs.
It may vary case by case, but I've measured the response of my system (with identical twin Rythmik subs) at 75db and at 95db and the difference is negligible. FWIW.