The sound from a natural gas regulator diaphragm.

Recorded with the Sony PCM-D50's mics in the wide stereo setting. XY stereo might not have picked up the traces of traffic in the left channel. Handheld without a shockmount, using the Rode Dead Kitten in fairly high wind. From the Senator David A. Croll Apartments, née Rochdale College, 341 Bloor Street West. Run time 45s, with a short fade added at the start and longer fade at the end, but otherwise unprocessed.