Using two PRs in same system, tuned to different frequencies?

[Silent Screamer]

I suspect they are killing a nasty resonance.
What is the c/o frequency?
What is the max enclosure dimension?
WHG

That one is probably no bigger than 1 cubic foot...

Planned sub has no maximum size, but TC Sounds recommend two options.

Dual VMP
Size Volume Number of VMP’s Moving Mass Tuning
12″ 6.4 ft3 2 × 18 in 1550 g 18 Hz
Very Large Dual VMP
Size Volume Number of VMP’s Moving Mass Tuning
12″ 8.4 ft3 2 × 18 in 1650 g 15 Hz

Due to the sheer size of the drivers it comes down to how small a box you can practically use.

Current design is 600mm x 600mm x 700mm internal, for 252 litres capacity (8.9 cu ft) minus drivers, PRs and bracing.

Best guess without working it out miscellaneous fill probably accounts for 50 litres. Which is where I roughly want to be on the lower side near the 6.4 cu ft (181 litres) number.

Today I will attempt to try workout the volume of the bracing, PRs and driver. I can alter height up and down a bit to adjust as needed.

 

[Silent Screamer]

Just realized this isn't a thread I started, sorry OP for hijacking your thread

 

[wonderfulaudio]

Fb with both PRs should actually be higher than what you'd get if you use either PR alone. If the Fb with one PR is 25 Hz and with the other it's 50 Hz, with both PRs in place Fb will be higher than 50 Hz, not between 25 Hz and 50 Hz.

Just like you'd end up with if you use vents sized to achieve two different resonance frequencies with the same enclosure.

In the above case, at 25Hz one PR is loaded but the other one is unloaded, does the system work below 50Hz at all?