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I record sounds with the simple same equipment which consist of my laptop and a microphone, both in my home and my office. The sounds are very clear which I record in my office. But, in my home, there is a terrible noise that I normally cannot hear.

When I make Listen -> "Listen to this device" checked in microphone properties in Windows operating system, I can hear the same noise in real time.

I cannot find any other difference between my home and my office except a cell phone base station. There is a base station next to our home. Can it produce this effect? if it cannot, I am open to any idea and suggestion.

Thanks

  • It sounds like you're using the same laptop/equipment in both places. Have you tried different areas of your home? It could be background noise from a refrigerator/hvac/etc or some kind of interference from Wifi/Wireless Phones/etc being picked up by the laptops audio circuits. – Bill Sep 22 '14 at 18:38
  • Can you post a sample? There are several possible answers, but without knowing what kind of noise you are talking about it's hard to say for sure what the problem is. – Christian van Caine Sep 23 '14 at 1:26
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Most likely this is the result of poor isolation of the ADC(analog to digital converter) in your laptop's audio hardware. Typically, without power conditioning, there are large amounts of variation in the power level that actually comes out of an outlet.

If audio hardware is not properly isolated and conditioned, these variations in power level (which can also be further caused by power consumption within a computer itself) will result in a very noticeable variable buzzing on the audio capture.

It's impossible to say for sure that this is what is happening given that you haven't posted audio samples, but it is my best guess given the situation. If you can post audio samples then I can confirm this. Your best bet to deal with them if that is the problem is to try a) running from battery power and making sure that your computer isn't working on anything else at the time or b) get an external recorder or capture card with proper isolation on the analog to digital converter.

  • If I let my laptop work with only battery by unplugging power adapter, the noise is gone. I think our electric network has some problem with harmonics. – adba Sep 24 '14 at 8:13
  • It isn't exactly harmonics. It is a shifting voltage level. Processing an analog signal requires a consistent voltage to compare to in most analog to digital converters. When that power level shifts, so does the perceived signal. Good power isolation prevents that. It is basically the digital version of ground differential (though that is a slight over simplification. ) – AJ Henderson Sep 24 '14 at 13:36

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