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I have a noisy neighbor (unreasonable and hostile) generating low frequencies that are disturbing. I'm at the point where I realize I need to just build some kind of barrier, and also buy better windows and doors.

So I am thinking of building a short wall (maybe 7 ft tall) to absorb or redirect the low frequencies (40-80Hz). Building material will be double brick, high density. The impact on my house is worst in the section directly facing the brown wall, hence why the wall is short.

illustration showing my house and the neighbor

The horizontal brown line shown above is meant to be the wall.

Before I start, I am concerned that the barrier will maybe allow the sound to pass around (or above). I suppose some sound is to be expected, but I want to eliminate most of it.

I just want to find out if my approach makes sense, or whether I should also be looking at some kind of DIY "bass trap" shape of this wall to absorb even more.

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  • $\begingroup$ Are you sure the neighbor won't move the source of the noise 5 ft left or right? $\endgroup$
    – SF.
    Commented Jul 21, 2020 at 12:24
  • $\begingroup$ Yeah, it is originating from their HiFi system which is stationary. $\endgroup$
    – Torbjørn Kristoffersen
    Commented Jul 21, 2020 at 12:27
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    $\begingroup$ We had this issue from a house, we the set up our HiFi and drowned them out, even our other neighbor helped... And no more problem. $\endgroup$
    – Solar Mike
    Commented Jul 21, 2020 at 12:47
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    $\begingroup$ You might be able to apply some of the methods mentioned in, How To Block Out Low Frequency Noise ( 6 Hacks That Worked For Me) $\endgroup$
    – Fred
    Commented Jul 21, 2020 at 13:28
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    $\begingroup$ @SolarMike Sounds like a successful experiment in active noise cancellation. You should write a paper :) $\endgroup$
    – Phil Sweet
    Commented Jul 22, 2020 at 22:58

4 Answers 4

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You may try to build something like highway sound barrier. They say that modified acrylic sheet is the best material for this, and I guess it's cheap.

Other option is not to build wall, but to insulate your house, using cork. Cork panels work very well for sound insulation. Especially if you manage to get egg crate shape, though it can be expensive depending on the area.

This looks to be the cheapest variant. I haven't tried it so I can't say.

But probably the cheapest and best option is the non-engineering approach. Try once again to talk calmly and reasonably with the neighbor. Explain how it affects your life. Just try not to get pissed off if it fails. If it fails, well you should check your local regulations about the noise levels and hours when noise is forbidden. If the bass is present at these time or is too loud, unfortunately, you will have to call the authorities. One or two fines will calm him down for sure.

I know how nasty a loud bass can be, for me it was even one of the reasons to move out. Good luck with this, and try not to stress too much. The solution will appear for sure.

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  • $\begingroup$ Thanks everyone for their answers $\endgroup$
    – Torbjørn Kristoffersen
    Commented Jul 22, 2020 at 11:39
  • $\begingroup$ I believe insulation is the best of the two options here as the sound will most probably diffract around the barrier (due to the very low frequency - large wavelength). Nevertheless, I believe too that the "non-engineering" approach is ideal (it's more like a "reducing the noise at the source" approach). $\endgroup$
    – ZaellixA
    Commented Nov 20, 2022 at 17:13
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The wavelength of sound at 40Hz is about 28 feet.

However tall the wall is, the sound will diffract over the top of it and spread downwards on the far side.

If you made the wall about 5 wavelengths high, it would be fairly effective. But I don't think your building regulations will let you build a 140 foot high wall, even if you can afford to do it!

The bass sounds from rock concerts, music festivals, etc, can be heard miles away from the venue. The answer to your problem is get your local environmental protection department to silence the neighbour, by taking him to court and/or confiscating his sound system, if he doesn't want to cooperate.

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  • $\begingroup$ How about diffusers mounted on the wall ? $\endgroup$
    – Torbjørn Kristoffersen
    Commented Jul 21, 2020 at 15:00
  • $\begingroup$ @TorbjørnKristoffersen This answer is correct. I live some 15 miles away (and higher up in elevation) from a concert venue used in the summer and we can hear the music very well - even to being able to recognize songs... Don't find it an issue though. Basically I don't rate your chances. $\endgroup$
    – Solar Mike
    Commented Jul 21, 2020 at 18:14
  • $\begingroup$ @TorbjørnKristoffersen, efficient diffusers for such low frequencies have to be several metres deep, which I believe makes the approach non-feasible. $\endgroup$
    – ZaellixA
    Commented Nov 20, 2022 at 17:15
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Short frequency noise will tend to go around and even through objects, soil, or foundations to your home, as base humming sound.

For 40 hertz or wavelengths of 5-10 meter object of the sizes of the same order are transparent.

A lot of bass noise travels through foundation.

Sound absorbing panels may be more effective.

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  • $\begingroup$ Shouldn't the brick wall absorb sound though, seeing that it is dense? How about mounting absorbing panels onto the brick wall as well? $\endgroup$
    – Torbjørn Kristoffersen
    Commented Jul 21, 2020 at 13:36
  • $\begingroup$ There are special fabrics covering acoustical foams used in the malls and large spaces. The do help. But bass noise is hard to stop. $\endgroup$
    – kamran
    Commented Jul 21, 2020 at 18:10
  • $\begingroup$ I believe that sound absorption is not a solution here. What is needed here is sound insulation, which most often than not results from reflections of the sound energy towards the source. This is usually achieved with impedance mismatches (layered materials). For very low frequencies though (such as the OP's) this is not efficient either. These frequencies lie in the "mass controlled frequency region" and the most efficient way is to introduce (as the name implies) additional mass. Build a heavy construction! Unfortunately, if this is a barrier, sound will most probably diffract around it. $\endgroup$
    – ZaellixA
    Commented Nov 20, 2022 at 17:18
  • $\begingroup$ @TorbjørnKristoffersen It's not that straightforward. You want to dissipate the sound energy. Just being heavy doesn't dissipate anything. Example: does sound travel better in water or air? Wood or steel? On the other hand, sound travels very poorly between the air-water interface in both directions. It's about impedance matching which is tough when your wall is not very large and there is air going around both sides. $\endgroup$
    – DKNguyen
    Commented Nov 25, 2022 at 14:59
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As others have mentioned, a brick wall of any reasonable mass or dimension will be almost completely ineffective.

If the goal is to reduce the SPL at only a specific, relatively compact location in your home (e.g. at the head of your bed), active noise cancellation may be feasible at very low frequencies. (Note that this will not control vibration, though, if this is also an aspect of the problem.)

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