I live close to a hospital and they make a generator test run once a month. That's an ultra deep sinus (~30Hz) that's humming along - you can hear it everywhere within the city.
It's was super easy to measure using a Sensirion Differential Pressure sensor. They have a few extremely sensitive models that have a 100Hz sampling rate (50Hz useable after Nyquist) - also: you can sense washing machines (from vibrating buildings) with it 2 blocks away.
What is the sensor attached to? And how can you pinpoint the source direction of sounds with it?
The product listing says something about a manifold, it looks like a raw component with 4 pins or so.
https://sensirion.com/products/catalog/SDP510
Sensirion SDP600-25Pa
SDP600-25Pa --- I2C ---> ESP32 --- UDP over Wifi --> Linux Host with simple Python recording script
Very rough pin-pointing is possible: plastic kitchen funnel which is attached to the sensor using a short hose.