A person posted on Home Improvement Stack Exchange the steps they took to identify a hum that was bothering them in their home. There are some good takeaways for people looking to do something similar at their places.
----- from https://diy.stackexchange.com/questions/77804/annoying-vibration-deep-humming-noise-in-home -----
I am experiencing noise and vibration in my home.
I purchased a seismometer (infiltec) that shows there is vibration (below 20 hz). The software allows fast fourier transform giving frequency signature. This tool has limitations in that it is not calibrated and it only detects vibration below 20hz. We humans can feel vibration up to 80 hz ... I haven't identified any low cost tools with which to do that. The Instantel blastmate would do it but it costs on the order of $10k as near as I can determine.
I purchased an infrasonic monitor (infiltec) that measures infrasonic (below 25 hz) noise. The same software is used as with the seismometer.
I purchased a (Tascam) recorder. It has microphones that record noise with a flat response to 20 hz. It also captures noise at frequencies below 20 hz but I don't know where it cuts off.
I purchased (Virtins) software pro version ... it includes a Spectrum Analyzer and an Oscilloscope with bandpass function, all of it on your computer. The software can be used to analyze the WAV file recorded on the recorder.
I purchased two (Behringer) measurement microphones. I mounted the microphones on construction tripods (high enough to avoid ground plane effects) and set them on a 5 meter baseline in my backyard. I connected the microphones to the recorder. I pointed the microphones at a suspected source and made a recording when the vibration was present.
I was able to spectrum analyze the recording to find the peak frequency. I used a bandpass filter function to isolate the peak frequency. I was able to use the oscilloscope to measure the time difference where the sine wave crossed the axis for each microphone. I was able to determine a direction using the time difference. A second recording at a different location allowed me to triangulate on the source.
The source is machinery at a house being used as a greenhouse to grow marijuana. Unfortunately its licensed under Health Canada MMAR regulations.
MMAR rules were revoked in March 2014. Unfortunately the MMAR crowd appealed in court and won an injunction until the case is decided. The judge heard final arguements 1 May 2015 and reserved his decision. Thats now 10 months ago ...
Its a real problem because the municipality I live in won't enforce its bylaws. There is no point in going to court ... because the MMAR case judge could make a decision tomorrow.
We now have a government that wants to legalize marijuana and a crowd of people that want to grow their own ...
But there you go ... the vibration is caused by infrasonic and low frequency noise ... noise you likely can't hear. In my case its caused by machinery at a distance over 30 meters away. It could be a faulty bearing. It could be the house acts as a giant speaker due to vibration in the grow op. It could be too much air being forced out of too small openings. etc.
I'd bet similar results would be found for people complaining of smart meters ... where in fact its more likely someones heat pump.
Scotland Government has a good report on Low Frequency Noise. It was produced by Casella 2001 for Department of Food and Rural Affairs (DEFRA)
Cost of tools ROM $2000 CAD.
