I'm pondering the following box parameters:

The 4 Pi Pro has 3 cu ft with the horn center about 20" above the floor,

The JBLPro recommended enclosure guide has 4 cu ft with the horn center (perched on top) about 28" above the floor with a clunky depth of 18",

My current box has 4 cu ft and the horn center 35" above the floor.

All 3 are tuned to 40 hz.

My ears, when I'm seated in my listening chair, are 37 " above the floor.

I haven't heard the 4Pi Pro since Lima, and that was in the auditorium with a Kilomax, so I have no way to judge the relative merits of the 2 different box volumes. Spkrman thinks the 3677 cabinet size with it's shallow depth sounds better than a shorter, deeper cabinet and it puts the center of the horn at nearly ear level which is why I built my current box that size: 21Wx32Hx13D.

I definitely trust Wayne's judgement on using the smaller box but the horn is low and I'm not comfortable with angling the cabinet upward, changing the coupling to the floor. If I go with the 3 cu ft box I'll probably build a lower chamber filled with sand to raise the height (*** that must be where Plant and Krauss got the idea for the name of their new CD!***), but, oh, my back.

OTOH, I really like the quality and quantity of the bass and lower mids with 4 cu ft and the new crossover.

What's a boy to do?