Audio Recording of HVAC system for corrective action

8th device I have tried, first WYZE. Fighting “noise suppression” technology in earlier devices. Want to capture sudden air pressure increase and rumbling in the HVAC in the attic that lasts 30 more or less after rumbling and pumping and thumping in the “box” and broadcasting through the ductwork. Sound I get is not useable, except for a sudden CLACK! that it seems to cause in house electrical. Audio not useable recording my own voice from 7 feet away. HVAC company using excuse that they cannot fix what they cannot hear. No – they do not know how to record either. Using the video CAM and it may be an older version. Apple IOS on iPad. Also there is a constant CLICK the camera makes that may be in the way of correct audio sensitivity.