2nd advantage of this solution, you always need to deliver signal to subs as early as possible since sub drivers are not fast in reaction. So your speakers receive the signal little later than subs. Result is matching phase of both drivers (normal speakers and subs) if sub signal arrives at your ears too early use subs’s delay or phase knobs to adjust.
works flawlessly.
any solution with dsp or 2nd preamp cannot beat above.
Enjou the music…