I'm seeking to have some of points clarified:

1. Quarter space (wall loading)

I understand that since you are only radiating into 1/4th of the total space when you put a speaker near 1 wall and a floor, the intensity of the sound will be 4 times as much (maybe a little more because of increased air impedance) as when suspended off the ground far away from any walls. I am unsure at what approximate frequency this effect stops being useful though. What is the general rule of thumb about which frequencies benefit and which don't?

2. Going from one driver to two increases the

**power**sensitivity by 3 db

I think I have this one figure out, so I'll explain what I think and then hopefully someone can confirm or correct it.

P=V^2/R. If you connect the two drivers in parallel then the resistance will be 1/2, so at first look there is a 3db gain. However since you keep the voltage at 2.83V, that corresponds to 2 watts, so no wonder its 3db louder. If you connect them in series, the resistance will be 2x as much and it will be at -3db at 2.83V. Only 1/2 watt is being used in this case though, so of course it will be down 3db.

In other words: How you hook up the speakers does not change the power sensitivity.

So, why do people always say there is a 3db gain then? This is the tricky part that I'm not sure on. My take is that since the drivers are trying to simultaneously compress the air at the same point, this provides a better impedance match for each driver. In other words, since the air is pushing back harder, the driver is exerting more force on the air and is thus transferring more energy into it (assuming that the excursion hasn't changed much). Thus, the power sensitivity is increased. How all the variables add up to give a rather convenient 3db gain, I haven't figured out yet.

Does that seem right or am I way off?

Thanks for the clarification.