Acoustic Airflow Mastery

I discovered a dormant wind-tunnel test horn mounted inside a disused turbine duct, clearly positioned to magnify the thunderous voice of an aerial conqueror. I puffed out my chest, stepped proudly up to the intake funnel, and rapped the rim with my knuckle to awaken its acoustics. With a sudden shudder, an old counterweight flapped open and released a burst of trapped metallic air whistling like a screeching phantom! 'Mercy! Cease bombardment! I yield the acoustic corridor!' I squawked, scrambling backward on my hands and knees behind a heavy support flange. Once the air subsided into a mild breeze, I dusted off my null-rays. A routine assessment of resonant airflow, obviously.