The track announcements ("Track No. 5", "Track No. 6") that repeat ad infinitum at train stations tend to produce a composite keynote of an F#.
Here is a clip with the F# keynote as well as some other errant pitches of E and D# on the periphery, evoking either F# Dorian or Mixolydian.
https://app.box.com/s/mzt1hi7il3mu64j51rjh
Most places that have some continuous flat-line sounds like HVAC systems (which can also produce rumble) can evoke pitch or you can easily add one. It would be an interesting exercise to ask people what pitch they hear if in fact there is a keynote from continuous brown noise.
Here is a clip with the F# keynote as well as some other errant pitches of E and D# on the periphery, evoking either F# Dorian or Mixolydian.
https://app.box.com/s/mzt1hi7il3mu64j51rjh
Most places that have some continuous flat-line sounds like HVAC systems (which can also produce rumble) can evoke pitch or you can easily add one. It would be an interesting exercise to ask people what pitch they hear if in fact there is a keynote from continuous brown noise.