One of many:

http://www.hostboard.com/forums/alte...port-size.html

You can also search on:
A5
825
828
... and 'port'.

other suggestions:

1) locate/read the "small v.o.t.t." paper
(and the large v.o.t.t. paper if interested).

This may be titled "smallVOT.pdf" (google)

2) Also of interest may be:
"soundpractices_spaltec.pdf"
Title: Altec "Voice of the Theater" Speakers for Hi-Fi ...a 1993 article by Jeff Markwart and John Tucker.


3) decide if you want wings, before defining the port size 'irreversibly'.
(per GM suggestion, possibly the thread above).


My wings and any mods are on hold for now, I am getting by with some 'subs' (as the kids would say) below 100hz.