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I have moved into an apartment, 4th floor, and I can hear a very annoying deep humming noise, I can even feel the floor vibrating sometimes. I am guessing the deep humming noise comes from the vibration resonating in the building walls. It is interfering with my sleep.

I am determined to find the source of the vibration and I am looking for advice.

First, I do not know if it comes from the same appartment or from outside. Most of the triangulating to find the source I have read are example of houses, not apartments, and they triangulate the source in an open environment, so my first doubt is how hard will it be to triangulate the source of the vibration inside the apartment? I am guessing there will be a lot of rebounds, and the vibration should come through the main columns or maybe even pipes. Is it realistic to find the origin of vibration inside the apartment, for example as coming from a column? What kind of hardware do I need? Will a couple of mics do or do I need something more specialized?

I am pretty sure I can handle the software part of analizing the signal for isolating the noise and triangulating, at least to have a good start, as I expect to have trouble triangulating the signal inside the building. But I do not know what kind of hardware it would be better to purchase to get the signal into my computer for analyzing. Someone in this same forum said he was able to locate the origin of some vibration by using two measurement Behringer microphones (annoying vibration, deep humming noise in home the answer by Whariwharangi). So I am thinking on purchasing a couple of these https://www.behringer.com/product.html?modelCode=P0118 and connect them to the computer using this interface https://www.behringer.com/product.html?modelCode=P0BJZ . I know there are better measurment microphones, but they quickly become expensive, above 1000usd a piece. I am open to suggestions for the hardware, even considering using other sensors instead of mics, from people with more experience.

Basically, I am looking for advice on how to find the source of the vibration noise. My main doubts are about using sound triangulation to locate the source inside the apartment and what hardware do I need, but also appreciate any advice on anything else that might help.

aionor
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  • I would ditch the electronics and use what God's given you - fingers and ears. Walk around your apartment, listen for where the noise is the greatest. Go barefoot so your shoes aren't damping anything, use your fingers and feet to feel for where the vibration is the greatest. Now that you have located the source, there's _probably_ not much you can do about it since you're renting and it's an apartment and you're not allowed to do much in the way of fixing, though some foam might help if something freestanding is moving... – FreeMan Feb 10 '21 at 11:50
  • I have tried. I could not find the source. I really would like advice on the hardware or anything else. – aionor Feb 10 '21 at 14:04
  • A oscilloscope app on a cellphone or tablet should do the job. it's an d Android both have them. Since you can feel the vibration, lay your phone on the floor, determine them hum frequency, and find out where it is strongest in your apt. I'd suspect maybe basement laundry. – Wayfaring Stranger Feb 10 '21 at 16:38

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There are accelerometers that can be used for vibration analysts. There are inexpensive ones for under 8$ for micro controller projects like arduous they do work well. Or you can spend more and get a premade usb device to measure the vibration.

I know in the past we had vibrations that showed up at a harmonic in the floor from motor driven pumps change the rubber pads and the vibration moved.

Since you sound like you like the data analysis the microcontroller project might be just what you want.

Ed Beal
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  • Can you give me one example of the usb sensor to measure vibration? I would consider it instead of the microphones. I like your suggestion of doing the microcontroller project (I have seen some examples in the web) but this is time sensitive since it is affecting my sleep and I live in a developing country, so I have to import this kind of stuff and it takes between 2 and 4 weeks to arrive usually. I do not want to take the risk of having to redo things and having to wait more. – aionor Feb 10 '21 at 15:54
  • Shopping questions are off topic but google usb accelerometer and several models pop up. These devices are fairly sensitive but start around 150$ and go up. They already do the data logging. I have used similar products to measure motor vibrations to predict when the bearings need to be replaced. Mounting them in the same location or axis helps to create repeatable data sets. – Ed Beal Feb 10 '21 at 16:06
  • I've checked usb accelerometers online, but got some doubts. The main issue with the accelerometer is that I can not use it to determine where the wave is coming from the same way I could with two mics, as the speed of the sound wave in the air is known (even if with some aproximations) but the speed of the vibration wave varies widly depending on the composition of the mass it is spreading in, which I can not know. I am thinking maybe I can do a "heat map" of vibration intensity to try to determine where it is coming from, but not sure if the differences will be enough. Any ideas? – aionor Feb 11 '21 at 05:16
  • Aionor, accelerometers will be much more sensitive to movement than microphones we detect bearing damage long before a class A sound meter can detect a change. Most systems provide at least 2 axis but many provide 3 axis movement details at sub sonic levels. 30 years ago we used sound equipment but accelerometers have been the standard 20+ and they are cheaper and more sensitive. HP makes one that is so sensitive only knowing the time in 3 days software can detect where in the world it is. And these are designed to detect shock waves to detect oil / gas below the ground that was 8 years ago. – Ed Beal Feb 11 '21 at 14:14
  • Ed I have never used an accelerometer (outside the mobile phone) so bear with me. Are you saying that one 3-axis accelerometer placed on top of the floor should be able to predict where the wave is coming from just from how the axis move? Sounds too wishful to me, but again I have no experience. From looking around, I have found that 3 accelerometers should be able to use TDOA to detect direction on 2D (one more datapoint to overcome speed being unknown). I am thinking to go the Arduino route for the 3 accelerometers. Any input from you is welcomed, if you think is overkill or anything else. – aionor Feb 12 '21 at 09:36
  • I think the arduino solution will be the least expensive and multiple inputs could be used for under 10$ each maybe 1/2 that. At one point we used accelerometers to adjust gold wire bonders (ic chip stuff) high speed cameras and accelerometers gave us the information to create perfect loops and bond smaller wire than anyone else in the industry. so can you go overboard sure, will it hurt? Additional data is usually helpful. We would mount accelerometers on motors and the software would tell us which end was going bad so a single point can be used with 3 axis if it is sensitive enough. – Ed Beal Feb 12 '21 at 14:15
  • Great, thanks a lot for the information. Yeah, it makes sense to get the 3 accelerometers since the price is cheap. I can try with one first and if I do not get good results, try a TDOA algo with 3 of them. Before I go to the Arduino forums to make sure I get everything I need for the project, one last question: the accelerometers I have seen online come in a small, tiny, pcb board. What is the best way to have it make contact with the ground? I am guessing that since it is so light it will absord the vibrations well, but any advice on how to place it right is welcomed. – aionor Feb 13 '21 at 10:26
  • With the motors we epoxied them in place but for temporary use we used a putty for surface vibrations positive contact using the putty increased the readings and gave some finer readings that were not seen by placing the unit on top. I don’t remember what it was but I thought it was modeling clay. – Ed Beal Feb 13 '21 at 15:25