How can I isolate against tram rumble?
February 22, 2016 6:27 AM   Subscribe

I live about 50m from a busy tram intersection. Ear plugs and white noise are no match for the low-frequency rumble. I am thinking about getting asymmetric double glazed windows, but I would like to make sure the windows are the main source of the problem, and not the window frames or any vibrations travelling through the building. Any advice on how I can make sure what the main source of noise is?

I live about 50m from a busy tram intersection, on the 5th floor of an apartment building built in 2012. There are three tram lines intersecting and the rails aren't straight (turns), so this is a major source of low-frequency noise. I must admit that I underestimated this. Ear plugs and white noise are no match for the low-frequency rumble, and moving is not an option.
In the apartment, the symmetric double glazed windows are an obvious weak point, letting through a lot of noise. They also contain ventilation grids, which only make matters worse.
Now I'm thinking of tackling this problem in three steps: 1) put heavy curtains, 2) install asymmetric (noise cancelling) double glazing without ventilation grids and 3) add rolling shutters.
I however want to make sure that the windows are the main source of noise, and that this three-step approach will be a significant improvement. Is there any way I can know whether the windows are the main problem and not something else? I am afraid that there might be vibrations travelling through the building, or that the window frames do not isolate well either, but I am not sure how I can identify this? All help is welcome!
posted by mlanduyt to Home & Garden (10 answers total) 1 user marked this as a favorite
If, say, you have a glass of water on your kitchen counter (or the floor), can you see the water vibrate when the trams are rumbling? If so, I think at least some of the vibrations are passing through the building itself. (Call it the "Jurassic Park" test.)

The changes you propose to the windows might still help, though. Also how is the apartment furnished? Do you have a lot of rugs and soft furnishings? That might help.
posted by mskyle at 6:38 AM on February 22, 2016 [2 favorites]

This isn't a direct answer, but I'll admit my first thought was, can you chat a bit with other tenants in the building, kind of bring up the noise and see if you find someone also as bothered by the noise as you, and if find out if they've found a solution that helps mitigate the rumbling.

Also, if you have any extra heavy blankets, etc., you could hang them up temporarily to test if there is any improvement.

Lastly, I know you are already trying white noise and ear plugs, but I do find my acoustic sheep sleep headphones sometimes work even better for me. (A soft headband with speakers in them). You do have to plug them into a device playing white noise (a white noise alarm clock or iphone), so if you move a lot in your sleep it is possible to get tangled in the cord, but sometimes when I can't sleep otherwise the headphones have made the difference.
posted by dawg-proud at 7:04 AM on February 22, 2016 [1 favorite]

How long have you been living there? Our flat is located directly above the London Underground. It was after we bought the place and in our first week living in the flat that I fully appreciated the noise and I thought "We've made a huge mistake".

But I got used to it in about a month. I didn't stop hearing it mind you, but I did get used to it. It's almost comforting sometimes (but I may be suffering from Stockholm Syndrome). I'm very sorry, I know how it feels right now but just wanted to give you hope.
posted by like_neon at 7:36 AM on February 22, 2016 [2 favorites]

In addition to the "Jurassic Park" test above, can you confirm that if you put your hand on the glass you feel a significant vibration? If you put one hand on the glass and the other on the wall, is there a noticeable difference?
posted by aimedwander at 7:47 AM on February 22, 2016

the asymmetric glazing is interesting. it's "asymmetric" because it uses two different thicknesses of glass. i am pretty sure that must be so that they resonate (wobble) at different frequencies - so hopefully only one will resonate at the frequency of the rumble.

if that's the case then i don't see why you couldn't simulate the effect by adding mass to the inner pane of glass. you'd have to think how best to do this - you want a fair amount of mass, fastened directly to the glass, perhaps using double sided tape to stick plates of something fairly heavy to the glass, and you need to be able to remove it afterwards without risking damaging the glass.

if you could do that, then you would get an idea of how much asymmetric glazing would help (if it doesn't help then it comes through the walls too).

i realise this must seem terribly adhoc and amateurish, but i think the basic idea is sound.

maybe a better way to do something similar is to buy a plywood or mdf sheet about the same size as the window, and place it against the glass, with some kind of padding (felt?) between it and the glass. that would likely also attenuate things. and again, if you could still hear the rumble, it would mean it comes through the walls.

really, what dawg-proud says, but with added physics bullshit. block the windows in some way and see if it helps. if it doesn't, it comes through the walls.
posted by andrewcooke at 8:01 AM on February 22, 2016

The short is answer is that asymmetric glazing won't make a significant difference to very low frequencies. That's the unfortunate physics of the situation. I can't find a spectrum for very low frequencies, but here is an example (Fig 5) showing no difference between symmetric and asymmetric windows around 125Hz (your rumble is certainly lower).

Getting rid of the ventilation grids may make some difference, but these low frequency sounds travel through all kinds of materials. Feel the wall, floor, etc. and I suspect you'll feel the vibration everywhere.
posted by ssg at 8:34 AM on February 22, 2016 [2 favorites]

Do you already have double glazed windows? Because I think you could put blue tack or a blob of putty on the interior-facing surface to achieve an assymmetric effect and see if that makes a difference before swapping out windows.
posted by zippy at 9:43 AM on February 22, 2016

Seconding dawg-proud. I'm highly sensitive to noise when sleeping, including low-level vibrations, and the Acoustic Sheep headphones are often the only way I can sleep when not at home.

They do carry a Bluetooth version, although I've yet to test them myself.

It's important to pair them with the right app, however. My favorite is SleepStream2 for iOS (it tragically isn't available on android.) The basic version is free, and you can change the frequency of the white noise to cover up other stuff around you. Check out the "Binanual Beats" section too - it does some weird sciency things with the noise frequency and tone that blocks out EVERYTHING else and also helps me get to sleep that much faster.
posted by beware the frog person at 11:13 AM on February 22, 2016 [1 favorite]

Response by poster: Thanks everybody for the kind replies.

To answer some questions:
- I have been living there for three weeks, so yes, I still have some adjusting to do.
- I already use a combo of ear plugs and acousticsheep sleepphones. I will try the sleepstream2 app.
- When I put some water in a glass in the bedroom, I can't see it vibrate. In the living room however, when the heaviest of the trams passes, it does shake ever so little (I have to pay close attention).
- I agree that the asymmetric double glazing won't help with the really low frequencies, but with the ventilations grids, all the street noise seems to pass very easily into the flat. So double glazing might still have a beneficial effect. I will try to check it by adding mass to the inside layer of glass.

Thanks again for all your replies. Any other input is always welcome!
posted by mlanduyt at 12:18 AM on February 23, 2016

Response by poster: In case anyone is looking at this thread having a similar problem: what really did the trick for me was the Bose QuietComfort 20 headphones. They are amazing. They simply cancel out all of the tram noise and they're quite comfortable to sleep with. As a matter of fact, I haven't slept so well in years as I do now with these noise cancelling headphones.
posted by mlanduyt at 4:11 AM on March 21, 2016 [2 favorites]

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