hello, 1) Trying to find the volume displaced by the peerless 831759 "len Moskowitz" 10" speaker. I looked around and have still been unable to find this data. I have heard I could compensate for the volume that the driver takes up by adding acoustistuff or other damping material inside- is this myth? Either way, i prefer to factor in the exact speaker volume. 2) Also, If i deceide to go with 2 ports instead of 1, is the length of each new port 1/2 the length of the original longer port? (assuming all are same diam) thanks in advance.