You'll need a low-frequency microphone, like a bass drum or tympani mic, but one designed for sustained sounds (the pickup should go down to 16 Hz or so). You may also need to insert a preamp prior to sampling. There is a good buildable circuit and mic recommendations in an issue of Elektor Magazine from about 7 years ago - if I can find it on their archive DVD I'll forward you a copy.
I can hear a sustained low-freq rumble near my house, but I've analyzed it as coming from I-540 traffic travelling through the ground creating interference patterns with high-power power lines near my house - a subharmonic of the 60Hz power frequency, below C1 of a handbell. I've looked up the geology of the area, and my house is along a buried ridge-like feature that borders Wake and Durham counties, that in theory could guide and amplify such a wave. The two cross each other near Leesville Road, then the ground feature runs along there to right by my house and beyond. Scott G. Hall Raleigh, NC, USA scottgha...@gmail.com *Although kindness is rarely a job, no matter what you do it's always an option.* On Mon, Mar 24, 2025, 9:52 AM Rob Parsons via TriEmbed < triembed@triembed.org> wrote: > Hi All, > > A project... > > I have been interested in monitoring environmental sounds for quite a long > time. > > Am I hearing "The Hum"? > https://en.wikipedia.org/wiki/The_Hum > My wife does not hear it. > > What is driving my dog crazy sometimes? > (Dog hearing range is 40Hz - 60000Hz) > > What hidden sounds is my house generating? > > There are some ultrasonic microphones. > https://batsound.com/ > <https://batsound.com/product-category/usbmicrophones/> > https://www.dodotronic.com/product-category/usb-microphones/ > > Some are very expensive. > https://roga-instruments.com/ultrasonic-usb-mic/ > > https://www.titley-scientific.com/product/omni-directional-ultrasonic-microphone/ > > My 'Analog Discovery 2' has a spectrum analyzer feature. Been looking for > a microphone or ultrasonic sensor that I could hook up to it. > > Anyone out there done any work in this area? > > Rob > > > > > > > > > _______________________________________________ > Triangle, NC Embedded Interest Group mailing list > > To post message: TriEmbed@triembed.org > List info: http://mail.triembed.org/mailman/listinfo/triembed_triembed.org > TriEmbed web site: https://TriEmbed.org > To unsubscribe, click link and send a blank message: mailto: > unsubscribe-triem...@bitser.net?subject=unsubscribe > Searchable email archive available at > https://www.mail-archive.com/triembed@triembed.org/ > >
_______________________________________________ Triangle, NC Embedded Interest Group mailing list To post message: TriEmbed@triembed.org List info: http://mail.triembed.org/mailman/listinfo/triembed_triembed.org TriEmbed web site: https://TriEmbed.org To unsubscribe, click link and send a blank message: mailto:unsubscribe-triem...@bitser.net?subject=unsubscribe Searchable email archive available at https://www.mail-archive.com/triembed@triembed.org/
