Benchmark or McIntosh....

One each in the front Left and Right corner.  One in the back of the theater,  mid-wall. Two on the left mid-wall and two on the right mid-wall. Room is 22x12x7 in the basement on concrete foundation and it will vibrate the floor. 

@roxy54 @stereo5 thank you for the info.  Definitely not wanting to do a Class A toaster in the room. 

I'd probably lean towards detail,  to be honest. Midrange would be nice.  Bass I have handled (lol!) The monitors cross over at 80, 90, or 100hz depending on the song and setting. I like the size of the McIntosh and the look. They'll run warmer,  which is a minus to me.  The Benchmark is small, but quiet and cool-running. I don't mind the sound being up front or my face. Again,  it's like a concert in here.  Almost a visceral experience. 

Not a joke @soix  . Information gathering and real- world feedback before I plop the money down. Like it said heart wants one,  brain says the other. Assuming that your are also looking at a picture of the room that is very old and nowhere near current.  In think the Salamander stand and the monitors are the only thing left from back then.  Multiple subs help even the bass out in the room, just following the Harman papers and advice from acoustic engineers (Anthony Grimani and others)  for bass management. 

@jasonbourne71 https://www.powersoundaudio.com/collections/subwoofers?filter.p.m.custom.woofer_size=21%22&filter.p.m.custom.woofer_size=21%22+IPAL

@curiousjim Room is 22x12x7 give or take a few inches.

@mm1tt77 100% agree on the McIntosh resale. It would be a pretty easy proposition. Krell on the other hand...would probably make the room into a sauna.

@panzrwagn You are spot on. I just am reluctant to change everything out. I could probably just change the front LRC and live with it. Something with more efficiency would help. 86/87db on the current monitors.  

Definitely considering Parasound monos, Musical Fidelity monos. Wadia monos. I looked at some others (Krell, Mark Levinson, Theta, Mola Mola, Wyred 4 Sound and others.

Every amp I've had has been SS. Several Adcoms, Sunfires, Musical Fidelity, and the Wadia...which someone just bought, so I'll definitely have to do something and soon. 

@onhwy61 Yes, exactly. Pushing boundaries and the limits of this system. The 21s are surprisingly musical...they come from the sound reinforcement/live sound realm. I would say more musical than the 18's they replaced and the 15s before them. 

@jastralfu It's my third set of NHTs, I 've owned since new back in the early 2000's. Stereophile Class A limited back in their heyday. Only work that I had to do was replace the crossovers a year ago (I think room correction "adjusted" a little too much and they went out)

@cundare2 I think most people on social media responded with the GIF from the original Back to the Future with Marty over a Doc's with the guitar. This tale tops that for sure.

@ditusa the 32s are not budget friendly. $22k+ a pop. There's always their 50 inch offering at almost $60k. And the unpriced (as far as I can see) 80 inch model...

https://www.aia-cinema.com/products/subwoofers/the32-sub-pro-ps.html

@helomech Yes, need the headroom. 86/87db for the monitors. 

@james633 Very good info. I cross over at 80 or 90 or 100 (depending on the song - I have three profiles in the preamp that I can change on the fly.)

I am going to give McIntosh monoblocs a go. As many stated (and I agree) if they aren't a good fit for me - I can resell fairly easy (or even trade-in for that matter) 

Was REALLY considering those Parasound JC5s. 1200w at 8ohm. They aren't the prettiest girl in the room, by far, but the performance looks top-notch.

@ditusa Going with McIntosh monoblocs for now. I think it ticks a few boxes for me and as others suggested, I can unload them if the fit isn't right. It does feel a little surreal - after years of seeing/dreaming about McIntosh gear, I'm finally a McIntosh owner. I hope my expectations are not let down. 

@ditusa I've seen his videos before, the first youtube link definitely. Sharp dude for sure. 

@ozzy62 thanks for your feedback.  You missed the part where I said that picture is from AGES ago.  Everything has been switched over to Power Sound Audio subs. You should not so hastily write off the 21. Very musical.  Will measure flat up past 1000-2000hz, not that one would normally cross over that high,  but it shows the capability and background of the driver. I guess I'll go update the pic. 

That pic was so outdated that the only component remaining is the CD player and the Salamander stand. 

75 percent music/ 25 percent movies.  But everything in this game is a compromise. Nothing wrong with some hybrid action. 

Just picked up the MC601 monos yesterday. I might be able to listen to them later tonight. 

@mrdecibel The B6 modules are currently removed from the system (and for sale!) The photo is now current, I deleted the old one with the "sub array" Currently, it's the M6 monitor on an IsoAcoustics Aperta stand which is on top of a single sealed 21" sub.

Looked at some options...just going to have to deal with the fact that the mains are going to have to be ported,

@overthemoon I did get a chance to listen. They are 

definitely not in your face. Laid back, detailed, and musical. Rolled off for sure. As others said, easy to listen to. I will have to do some room measurements/ correction before I make a final verdict. They look absolutely gorgeous though!

@emergingsoul The monitors themselves are not bi-ampable. With the bass modules attached, they would be. Also, $38,000 for a pair of mc901s versus $6400 for the pair of the MC601s

@emergingsoul The Paradigms I had were all mis-matched (see previous comments in this thread about the room looking bad) so I upgraded to 18" PSA subs. I was having some noise issues during certain parts of songs so I decided to try their new(ish) 21. I like the 21 more versus the 18s, so I ended up with the two up front and one in the rear. The sidewalls have a dual-opposed 21 on each side. It works well since I don't have to push them hard to get decent output in the room so it keeps the distortion low, which is the goal. Also, the McIntosh is dead quiet. The Wadia had a little noise if you got very close to the monitor. With the Mac, nothing but silence. 

Switched the speaker outputs from the 4ohm to 8ohm (speakers are 6ohm.) Completely changed the sound of the amp (in a good way) MUCH more to my liking now. Absolutely wild.