The M19 has way more bass and much more tonally balanced than an 816 since it's unloaded below ~156 Hz. What it has is chest pounding upper mid-bass, lower mids ~ the same as an A7 that allows for much greater efficiency from ~200 Hz all the way up to the HF horn's limits, so as already noted, it seems like a kick-a$$ sub system is the preferred route here.

That, or make a reasonable compromise same as me, AB and some others have done by using dual woofers in large cabs that at least in my case is better overall performing than when they were ~70 Hz compression horn loaded. In room, ~corner loaded, my ~20 ft^3/16 Hz Fb cabs are at least 103 dB/4ft eff. down to around 20 Hz.

GM