Will Subwoofer Help?


Although
1. My speakers have dual 10" subwoofers crossing over at 180Hz;
2. Speakers have 4ohm nominal impedance and 90+ sensitivity;
3. Power amp runs 300 WPC into 4ohom load,

nevertheless I'm wondering whether one (or more) good subs, set at
80 or 100Hz, would improve low end precision by taking full responsibility
for the very bottom range.

If so, given the power amp is taking preamp's XLR output, any problem in just using the single-end
output to feed the sub?
hickamore
Probably the reason some stuff sounds bloated and boomy on the bottom end is the source material. Nothing to do with your system. The best system cannot make poor source material sound good. This is one reason why audiophiles waste a lot of money. They think they can improve the sound of a sh!tty recording. They can't. Unless they get into their time machine and go back and improve the original recording and mastering.
hombre, thank you. Was just hoping for someone to confirm that. Free expert consultation is grand resource. Now I can quit chasing phantoms & go do some detail gardening or rearrange wine bottles. Like maybe everyone, too much dead time on my hands in a lockdown world. Too bad I don't have a novel in me. For once, people have plenty of reading time. 
for some real interesting reading on wikipedia type a search for "Dyatlov Pass incident" and read the article.
"The events of the past, through lapse of time, have fought their way, past credence, into the country of myth." -- Thucydides