Questions regarding soffits.

I am currently in the process of building my speaker enclosures simular to Mr sayers component design within the following thread. http://www.johnlsayers.com/phpBB2/viewtopic.php?f=1&t=5457 I have a few questions about the lower half of the soffit system. 1) I have seen that the majority of the time hangers are used within the cavity. on Mr sayers component design there appears to be nothing within this cavity? is this the case or is it lined with insulation. 2) if hangers are not possible within the cavity, what are the other options? 3) what are the differences between the different methods, performance wise?

depending on the size of your soffit components, the base area could have hangers or it might simply be a layer of rigid insulation and a the remaining space filled with lighter insulation. up top, you would also fill with the lighter insulation - leaving as much room as needed for any air flow.

Thanks Glenn