What should I do...bass upgrade path...MBM's? Upgrade 18" marty to a 21"...?
Currently, I have a mini Marty with a um18 that I am satisfied with overall for the low end, but I am looking to add some higher frequency mid-bass to my setup (yeah, another one of those "I want chest slam bass threads, sorry lol). I also have a ported Klipsch 12" sub I am using for a bit better response in my room and it has helped with a 50hz null I had. So I have one 18" and one 12" in a room that is roughly 2784 cubic feet (14.5ft x 24ft with 8ft ceilings). I'm not looking to necessarily increase spl, as the wife doesn't like the power levels I can get to already; just more 50hz-150hz thump.
My um18 is being run off a nx3000d (bridged) and is in the best place in my room according to rew.
Budget wise I'm looking to stay under $1k.
Option 1 - MBM's
Would you suggest 1 or 2 pa460 cabs?
My initial thought is to add 2 pa460 sealed/ported (not sure which would integrate better, or pro's/con's as a mbm here - help?) cabs sitting behind the "2 seat couch" up next to the "bar" wall. This would put them approximately 4.5ft away from the mlp, so not super nearfield, but pretty close. Or I could move the Mini Marty to the bar wall and stack the pa460's in place where the Mini Marty currently is, which would make them more nearfield.
Is there a go-to size and cutlist for pa460's for mbm use (like I found for the marty diy builds)? Is the PE 4 cu ft flatpack ideal? I'd probably build them myself to save $.
For mbm frequencies with the pa460's, what size cab is ideal - 3 cu ft? 4 cu ft?
Ported vs sealed for the mbm?
Which amp are guys using if I were to power 2 pa460's? NX1000D? NX3000D? Would I be better off selling off my NX3000D and jumping up to a NX6000D? Thoughts?
Option 2 - Upgrade Mini Marty 18" to a 21"
What are your thoughts on swapping out my um18 driver for a 21" that hits the mids better? I'd use my existing mini marty cab; is it too small for the benefits of a 21"? Would I need to upgrade my NX3000D to something stronger? I'm not sure this is a cost-effective venture vs building some mbm's though...?
The room pic & diagram is attached.
Source: HTPC w/madVR, Video: Epson 5040, 150" 16:9, Audio: Onkyo RZ 830 avr, 5.1.4 Atmos setup. 5 speaker Energy C Series: L/R C300's, C C-C100, SR/SL C50's, 4 in-ceiling Micca R-8c. Subwoofer: MiniMarty um18 w/NX3000D.