Hi Wayne,A while ago we corresponded about using your 7 Pi corner horns as bass horns. I said I would try and track down some good suitable drivers and get back to you. That was some time ago, but I have now tracked down some Celestion 18" motors a friend pulled out of a movie theatre.
For (domestic) reasons, a corner cabinet for these things would be less suitable than folded bins (lying sideways in corner alcoves). I haven't had a chance to check T/S specs for these particular drivers, but I think they will be similar to modern Celestion 18"s, ie:
Vas: 11.85 cu ft
Frd: 30 hz
Qts: .20
I've been thinking either 10 Pi's or Bigmouth PD 186's would do the trick. What do you think? My computer spits the dummy when I try to download the 10 Pi plans, for the interim could you just tell me the external dimensions (to see if they will fit in my house)?