I have found info on the use of two drivers in isobaric coupling, but what happens (in terms of sensitivity and box design math) if I use 4 drivers? Two should be facing out into the listening room, and the other two should be hidden inside the box, with isobaric coupling to the outter two.

The drivers are Peerless SLS-8 drivers, nominal 8ohm with about 87dB sensitivity each.

My plan is to put connect two drivers in parallel (giving 4 ohm), and then connecting two of these sets in series, giving 8 ohm again.

If I have understood it correctly, two drivers in parallel (mounted isobaric) end up with the same sensitivity as a single driver. (if this correct?)

If so, I am splitting the power (with two "4-ohm pairs" in series), but getting double the cone surface. Where does this lead me?

Can anybody tell me the overall sensitivity of this system?

Thanks,

Jennice