[mellowjammer]

I have owned 2 of these for years...current updates include the Ultramega (Dayton HF series) 15" & 12" drivers and big bump PR.  I have since built 2 new subs consisting of four 18" Dayton HO 18s each (8 total). I also have a Linkwitz Transform circuit on the 18s which extends their response to 15Hz useable output.  These dig very deep but I seem to be lacking in the midbass area and was wondering if the VMPS Largers could be used to fill in this area.  The plan would be to run the LFE channel from my Yamaha up to around 60Hz and send this output to the eight 18s.  Then the output to the mains (60Hz and up) would run to an electronic X/O.  I would send 60-175Hz or so to the VMPS largers and 175Hz up to my VMPS RM2s.  If I gave the Largers 1250 watts each from 60Hz to 175Hz, could I theoretically dial in the midbass punch that I'm missing?  This is in a large open floorplan with 17' ceilings throughout the first floor.

[mjmessina]

Are your subs ported? or have passive radiators?

I put two of the Dayton Audio UM15-22 15" Ultimax DVC Subwoofers in an enclosed boxes.  Gives a nice tight punchy bass.
I have somewhat of a large room (1200sq foot basement w/ 9ft ceilings).
These things pound your chest and they are not even being pushed.

[mellowjammer]

I had a Pair of JTR Captivators which are ported 18" drivers (passives, driven with around 1K watts each) which was great for movies but in my opinion was not tight enough for certain types of music (Jazz, acoustic, detailed stuff).  So built 2 sealed cabinets housing 4 Dayton 18s each, providing about 3cu ft per driver, which is a little small because they are being boosted below 20Hz and being fed 5000watts per cabinet.  These are also great for movies but not as tight as the VMPS largers.  The largers were great for music but would bottom out on movie peaks occasionally which is unacceptable.  Although I only sit 13 ft from the speakers & screen, the open space of the room is about 30-40,000ft³ and it's hard to pressurize the space. 
I guess my only question is "Can my 2 VMPS Larger Subs (with the Dayton HF Drivers & BB PR be used effectively for very high output in the 60Hz to 175 Hz region to produce good midbass thump with 1250 watts apiece."

[John Casler]

You might want to consider the UltraMega PR's for your LARGERS.

They do not bottom out, but still are quite capable on musical works.   

They might even be sufficient for your HT needs.

[mellowjammer]

5 quick questions:  Are these the TC Sounds PRs using the washers instead of putty?  Do they fit in the same cutout as the Big Bump PR?  Any other modifications required to add these?  How will it affect the sound?  Cost?

[John Casler]

5 quick questions:  Are these the TC Sounds PRs using the washers instead of putty?  Do they fit in the same cutout as the Big Bump PR?  Any other modifications required to add these?  How will it affect the sound?  Cost?

1) No the TC Sounds PR is TOO stiff and does not fit.
2) They do have washers, but you can fine tune with Putty too
3) They fit the same cutout, but "surface mount", using the same screw pattern on most subs
4) No mods should be needed, unless you have a screw pattern different from normal (unlikely)  They were made to have the right pattern.
5) They will play deeper, and with much more authority, while maintaining musicality
6) They are $115 plus $19 shipping

[Linkwitz Riley]

Oh are these the PSi PRs?  Do you set the correct # of washers on these before they ship?  If not, is the threaded stud on the front or rear of the driver in order to access it for adding/removing mass? When you say "surface mount" does that mean that they don't really fit the cutout correctly but the OD of the basket is big enough that there is a little edge that still makes a seal on the baffle?  Is there a gasket to fill the void of the cutout or are the screws pulling down and not seating against anything? I would hope not because nobody installs drivers/PRs like that.  It's not very clear how this works.

[RSorak]

The way he wants the PR's installed yes the screws are over air....All it takes to make the new PR's fit the holes is to enlarge the outer diameter about 1/8" I did this easily with a rasp on a drill.

The metal washers mount from the front, look at the other PR threads for pictures....

[DFaulds]

The way he wants the PR's installed yes the screws are over air....All it takes to make the new PR's fit the holes is to enlarge the outer diameter about 1/8" I did this easily with a rasp on a drill.

The metal washers mount from the front, look at the other PR threads for pictures....

From the pics I saw on the two threads they look very much like the CSS passives.

[John Casler]

The UltraMega uses the same OEM as the CSS.

It "does not" fit into the outside diameter of the VMPS, but it is designed to have the screws countersunk enough, and in the same pattern as the old VMPS, so it fits fine.

It uses metal washers (only needs 3-4 for most horizontal uses) and they do mount on a small bolt with easy access.

Since in most it will be surface mount, you do need to take care in placing and tightening the screws, so as not to pull it off center.

While most will find they don't need a gasket to have a very tight seal, some may want to try one.