Is the dog inside or outside the house?
Bearing going out in fan motor of AC? Bugs or critters in the wall?
Is the dog inside or outside the house?
Bearing going out in fan motor of AC? Bugs or critters in the wall?
A little more expensive than my "find a young person" solution (protip younger people can hear frequencies folks in their 20s+ can't) but it's still viable with enough money.Originally Posted by SunTzu
Last edited by Peally; 11-14-2018 at 10:36 PM.
Semper Gumby, Always Flexible
I hope you're right. I really do, because just one of those things managed to wipe out my entire crew in less than 24 hours, now if @rob_s has found that ship, there's no telling how many have been exposed. Do you understand?A little more expensive than my "find a young person" solution (protip younger people can hear frequencies folks in their 20s+ can't) but it's still viable with enough money.
Last edited by Guerrero; 11-14-2018 at 10:53 PM.
Nuke the site from orbit. It’s the only way to be sure.
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If your dog is a really good indicator, start at the breaker box. My guess is the noise is coming from a noisy power supply, it's just a matter of finding out which one. Shut everything off and observe. If your dog is fine, then start bringing things back online until you find the breaker with the irritant and chase down everything on that breaker.
If nothing inside your own dwelling is causing the issue, do you live in an apartment or townhouse that shares common walls? With the rodent population explosion this year, is it might be possible that a neighbor purchased an ultrasonic repellent that isn't working properly. They are supposed to operate over the hearing range of pets, but we all know tolerance stacking can be a thing.
Matt
It's a little tough to use the dog himself as the detector because he's otherwise deaf. He's also pretty old so he's acting weird anyway.
We had an issue with him running away several years ago and we tracked it down to (I think) one of my wife's camera battery chargers (she's a professional photographer) and once we unplugged that he stopped running away.
Lately he's been trying to get away again, which has me thinking it might be a similar issue.
He may still be a good sensor though. Is there a specific room in the house he won’t go into or stay in? I think you’re on the right track regarding things like chargers. See if you can track down anything new to the environmental since you noticed the change in your dog (I realize you likely did this already). After that, I would look at the oldest electronics in the room. I have heard squealing from old TV’s, monitors, chargers, and light ballasts (more humming than squealing).
Once you start looking at measuring equipment, you’re into fairly specialized stuff to have a microphone that can accurately read up to 60KHz and report on it including a digital sampler at 192KHz to get the Nyquist frequency above the dog’s hearing range.
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So if you're using something like this, what are you looking for? I'm convinced our ceiling fan is emitting a barely-audible squeal, but the wife insists she can't hear anything.
"Sapiens dicit: 'Ignoscere divinum est, sed noli pretium plenum pro pizza sero allata solvere.'" - Michelangelo
Human hearing is roughly in the 20 Hz to 20 kHz range. If you think you're hearing a "high pitched" noise, you could use it to see if it detects anything in the (for example) 15 kHz range.
Couple ideas.
If you have recently installed electronic dimmers, the circuitry may be oscillating due to the way the dimmer works. This oscillating generally is not well regulated, and has lots of square waves, which can and do generate harmonics of the original frequency. It's possible to have high frequency noise this way.
Same for fans, which are inductive loads. If the noise goes away when the fan is on high, you might have found the problem.
And of course the modern lamps themselves can also emit noises, or harmonics of noises.
An older power supply can emit noise, but these are usually at lower frequencies i.e. 60 Hz or harmonics. Usually people complain about "hum". Doesn't sound like your problem.
A spectrum analyzer app can work. I don't know what the frequency response of a smartphone is.
I just downloaded "Spectrum", a typical free app from the Apple store. It seems to indicate a coverage from base to north of 16K.
The FFT size is 512 samples; and runs in real time (pretty amazing considering I used to program FFTs byte-wise using discrete circuitry in an, ah, Military Application back in the Dark Ages.) Whether the free version and iPhone is sufficiently sensitive to detect "high" frequency is probably dependant on what you are hearing, but might be worth a try.
A dedicated microphone / transducer, and some circuitry to buffer / sample it into a PC, with some either dedicated or roll your own software, will obviously cost more (sometimes a lot more.)
SoI guess I would try the easy stuff first (dimmers?) then look at a spectrum analyzer (free) and lastly maybe try the higher end stuff.
Last edited by RJ; 11-29-2018 at 07:41 PM.
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