magnifier driver

["Tesla list" <tesla-at-pupman-dot-com>]

Original poster: "colin.heath4 by way of Terry Fritz <teslalist-at-qwest-dot-net>" <colin.heath4-at-ntlworld-dot-com>

hi all,
         im currently building my maggie and have a few questions.
how much gap should i leave between primary and secondary due to tight
coupling?
i have a 21" primary so i was thinking the driver secondary could be 16"
heavily wrapped in poly or shrink wrap(saran wrap)
i thought 2.5" would be plenty clearance all round as the driver is only low
frequency.
am i correct with this?
cheers
colin heath