In general, regardless of specific subs, what is better, a single sub or dual subs?
Dual subs will provide greater overall output vs. a single sub, and smoother FR at the listening position.
I have vaulted ceilings in my room, which reach a height of 12', which would give my room a total volume of approximately 2,500'.
Your room is still not very large, and dual PB-1000s should still work very well in it.
That said, if your budget and your plans permit it, one approach would be to spend a greater portion (but not all) of your current budget on a single better sub, and then save up the additional funds required for a second, matching sub.
In which case, you have many more options, including:
- PSA XV15 ($799, shipped)
- SVS PB12-NSD ($769, shipped)
- PSA XS15 ($749, shipped)
- Outlaw LFM-1 EX ($649 + shipping)
- SVS SB12-NSD ($649, shipped)
- Rythmik LV12R ($589 + shipping)