My 4Pi's are ruffly 6.5 cu.ft., with PSD2002 and Delta Pro 15s tuned I think to 42Hz.

I don't have time to build a subwoofer so I was thinking about a commercial unit.

Would I adjust the port length of my 4Pi - and tune it to a higher frequency - perhaps 150Hz (is this possible). Or do I modify the crossover so the cutoff for the Delta Pro is higher?

Hakn

Thanks for the quick response!
Please send a copy of the Lab12 based plans.

Hakn Sr.

Next challenge is trying to get the right audio synergies..
The 15in Delta Pros in my 4 Pi Towers (JLapaire - tune to 42Hz) in comparison to the LAB 12 have a difference in sensitivity by more that 10dBs.
In a 3.5ft3 enclosure (ported) I would have to apply lots of power at the LAB 12 - something like a QSC RMX1450(900 Watts Bridged Mono into 8ohms) or RMX2450 (1200 Watts Bridged Mono into 8ohms)- Lab 12 is a 6 ohm speaker. Will this work?
So I don't overlap the low end - I would high-pass the signal going to the Lab 12 at 125Hz (? - thinking out loud).
Alternatively - I could use a plate amp.
Using the line level inputs and outputs, which will remove the bass from your Delta Pro 15in drivers. Adjust the level controls to match.
I would prefer using the Pro-amp approach with high-pass, as I want to leave the 4 Pi's alone - they sound great!
Haknhendrix Sr.