The JAES papers I've read match my experience: a good listener can locate the bass speaker down to 40-50Hz, and definitely at 60Hz. The literature recommendation is to maintain stero bass to at least 50Hz. When I put a >30Hz woofer on the floor next to a line array, the sound stage image physically drops, and this is why I use bass line arrays with line array speakers. I never use subwoofers, and I am happy with close-to-flat 30Hz room boosted bass. Perfecting 80-1,500Hz human voice is my main goal.

You will need to listen and compare line array bass to on-the-floor bass. The biggest waste of time and money is to do it wrong then do-it-over. There are lower cost good sounding 12" woofers.