SVS single vs. dual woofer box subs (1 Viewer)

I noticed something about the SVS box subs. The dual woofer models have tunings of 25, 20, and 16 Hz. And the single woofer models have tunings of 20, 16, and 12 Hz. Is there a specific reason for this?

I can't remember the order that the box models were released, but I think the single Ultra came out after the dual Ultra. I wonder if it is a logistical decision? Would a 12 Hz option for the dual woofer models mean a much bigger box? I bet there are some bass fanatics who would love a 12 Hz tuning on the PB12-Ultra/2.

Thoughts? Ron and Tom?

Naturally lower tuning means longer port, so yes size should go up.

The dual woofer models came out before the single woofer models. They use straight vents inside the enclosure and offer 25 Hz, 20 Hz and 16 Hz tuning points.

The new single woofer models (PB12-Ultra, PB12-Plus, and PB12-ISD/V) all use a new box (almost as large as the dual woofer box), and a new venting configuration. Internal 90 degree elbows are used on the vents to extend the length, and this in turn supports a native 20 Hz tune with all ports open.

Moving to a native 20 Hz tune with all three ports open was smart, because it allows a 16 Hz tune with dual ports open, and this minimizes the potential for port chuffing in this tune.

I don't recommend the 12 Hz tune (underported IMO), especially considering that the 16 Hz tune digs to 13-14 Hz quasi-anechoic.

Nice. Thanks for the info, Edward!