This doesn't quite feel right.
| Now, if you build another identical box seperate and do NOT increase the power applied, you won't gain a single db. If you double the power applied since your power handling doubles due to having 2 motors, you gain 3db. |
I suppose I don't fully understand what it takes to acoustic-couple...
I would think that increasing the diaphragm would have some effect on efficiency. So adding another speaker even without more power would add spl's. I think.