The relationship your subwoofers have with the rest of your system should be stable. If the bass on a certain recording is too strong for you then use a bass tone control if you have one.
Well integrated subwoofers should not need any adjustment. Poorly integrated subs can be all over the place with different recordings.
I know what REL says. Their method of integrating subs is for people who do not want to spend any more money to do it right. The right way is to use only low level connections and a dedicated 2 way crossover like this one https://www.minidsp.com/products/minidsp-in-a-box/minidsp-2x4-hd.
Well integrated subwoofers should not need any adjustment. Poorly integrated subs can be all over the place with different recordings.
I know what REL says. Their method of integrating subs is for people who do not want to spend any more money to do it right. The right way is to use only low level connections and a dedicated 2 way crossover like this one https://www.minidsp.com/products/minidsp-in-a-box/minidsp-2x4-hd.