A couple of pictures from the presentation of my Master Thesis
'Studying the Acoustic Parameters of Micro-slotted Panels'
Micro-slotted panels in duct bend,
as seen from the fluids point of view.
The duct bend taken apart,
this is how one of the panel configurations looked like.
Measurement set-up outside the reverberation room
Adjusting the round-mic. in the reverberation room
The test rig I made for the two-microphone method.