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Topic: Antidote To Subwoofer Noise Nuiscence (Read 203 times) previous topic - next topic
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Antidote To Subwoofer Noise Nuiscence

I am having problems with a neighbor playing low volume drumming music in garden which can be for up to 8 hours  whenever we have a sunny day. Complained to local council plus Environmental Health but they won't help so may have to move.

Whilst I was reading upon noise cancelling headphones using frequency inversion, I wondered if same theory could provide a solution for me, noting that it can be used on a larger scale for industrial noise etc.

Plan A: Initially I thought of using a microphone, amp and sub woofer to replay the drumming noise inverted, thus cancelling it out (providing of course that there is equipment available to invert the source audio).

Plan B: Then I read another article about stereo speaker being out of phase causing the resultant audio level to be very much reduced. Maybe if I just replayed the drumming noise through a standard amp & subwoofer but tweaked the speaker polarity so it was out of phase with the source one hopefully cancelling it out.

Either of the above would be preferable to moving house but would appreciate any expert feedback before I start experimenting thanks.


Re: Antidote To Subwoofer Noise Nuiscence

Reply #1
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Plan A: Initially I thought of using a microphone, amp and sub woofer to replay the drumming noise inverted, thus cancelling it out
In the real world that won't work.  :(  You need the exact-same volume, exactly inverted.   It could  work to some extent if you could put a microphone near the offending noise, and if you didn't move once you get the sound waves cancelling.

It works with headphones because the microphone is close to your ear but outside of the headphone so it can pick-up external noise (exactly what you ear would hear) without picking-up the "cancellation sound" from the speaker inside the headphone.

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(providing of course that there is equipment available to invert the source audio).
That part is easy!    You can just reverse the connections to the speaker. ;)  (Or, it can be done electronically or digitally.)

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Plan B: Then I read another article about stereo speaker being out of phase causing the resultant audio level to be very much reduced.
If you reverse the connections to one stereo speaker the bass will be almost completely canceled.    Plus  you'll get a "spacey" "stereo widening" effect as the other frequencies (shorter wavelengths) bounce-around the room combining in and out of phase, depending on the room acoustics and where you are in the room.  

...If you just play a regular (in-phase) high-frequency stereo test tone, the distance between your ears means there's a phase difference between the left & right speakers and slight movements of your head will make drastic volume changes as the left & right (and reflected) soundwaves go in-and-out of phase.   i.e. 10kHz has a wavelength of about 1.3 inches (3.3cm) so half that difference is 180 degrees. 


 
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