Greetings all, I have rebuild my experimental low frequency enclosure to allow rear driver mounting, and I would like to measure it. However, we are still snowed in, so I was reading on the near-field measurement as proposed by DB Keele Jr in his 1974 paper. However, my driver ALTEC 515 has a hole, protected by wire mesh, in the middle of the dust-cup, so I was wondering if the method will work. Anybody has an experience? Could I tape over the hole for the measurement? Kindest regards, M