2. misc-audio
  3. 140089-1783

Stopping Vibration from Walmart trucks

I have for the past two weeks had problems with my living room and master bedroom having a low frequency issues in the center of each room, when certain trucks are delivering at a Walmart about 100 yards or so away.
Does anyone know how to disperse the low frequency waves in the room. As you move towards the walls, even in the direction of the Walmart the subwoofer effect goes away.

I have probably contributed to the issue by taking down an old wooden fence and replacing with a wrought iron fence, so we could enjoy a greenbelt between us and Walmart. My wife and I noticed the problem about two days after replacing the fence. It is only noticeable on some evenings with certain trucks, and is actually louder in my living room than at Walmart.

I was wanting to add bass traps are whatever is needed, as I don't want to go back to the fenced in backyard.

Thanks,



acman3
folkfreak's avatar
folkfreak
1,349 posts
 
It does seem however that the OP has a secondary issue in so far as the room itself is exacerbating the sub-sonic issues. Bass traps will not help as they are also tuned to the audio range and cannot deal with sub 10Hz (think how large such a bass trap would need to be)

I wonder if the issue is the floor acting as a resonator then mass loading the floor in the appropriate manner might break things up?

Failing that as others have suggested an isolation fence could be a good idea -- many suppliers make such a thing but again it will not deal with the sub-sonic problems ...
geoffkait's avatar
geoffkait
23,365 posts
 
If a suspension is exceptionally floppy it means the resonance frequency is low, not high. If the suspension is very stiff it means the Fr is relatively high. Resonant frequency is proportional to the square root of spring rate (all springs total). Almost all isolations systems extant deal with vibration with frequencies outside the audio range, I.e., seismic vibration, in range 0-20 Hz. Like that produced by Walmart trucks.
acman3 OP
4,337 posts
 
Folkfreak and all, the big problem is the room resonating. It is not a problem caused by speakers, although I am sure it affects both speakers and turntable.

I was hoping I would be able to do something inside the room like Bass Traps. I will look into the issue via the internet, but like all, I was hoping for a magic bullet, I had not thought of. I guess I have to put the fence back up or live with it.



 
folkfreak's avatar
folkfreak
1,349 posts
 
@acman3 we get it! All of the responses you received were relating to external subsonic vibration. That is the problem you are trying to work with and that is what springs, Herzans and the like will deal with. You cannot use a bass trap -- it would have to absolutely enormous!

Our solutions are practical in so far as if it proves impossible to remove the source of the subsonic issues (which frankly it will be, subsonic vibration is present all of the time from mini earthquakes and the like) then the only solution is to isolate the audio equipment from its effect which the solutions we are suggesting will do.
teo_audio
2,197 posts
 
The issue is likely airborne, as he said it went up to being noticeable when the fence went down.

No spring will help this.

I sent a pm on what might work.
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