Interference spikes with DMM-6

cz32

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Jul 6, 2020
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Hello just purchased a DMM-6, installed REW and loaded calibration file all good. When I'm running measurements I'm getting a spike at 50hz of over 130dB and then lower spikes further up the spectrum. I have tried another computer, one of them is a laptop which is on battery/unplugged. I've turned the power off to the whole apartment and it reduces but doesn't go away.

I've attached a graph, orange is loud, green was disturbingly loud, blue is with the speakers muted in a quiet room, mic in the same place.
Second image with quiet room and smoothing turned off.

Any insight appreciated.

Thank you.
 

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linearphase

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Joined
Jan 17, 2019
Messages
59
Hello just purchased a DMM-6, installed REW and loaded calibration file all good. When I'm running measurements I'm getting a spike at 50hz of over 130dB and then lower spikes further up the spectrum. I have tried another computer, one of them is a laptop which is on battery/unplugged. I've turned the power off to the whole apartment and it reduces but doesn't go away.

I've attached a graph, orange is loud, green was disturbingly loud, blue is with the speakers muted in a quiet room, mic in the same place.
Second image with quiet room and smoothing turned off.

Any insight appreciated.

Thank you.
Where do you live? If you have a 50 Hz mains it could be related to that. Try a different location away from your house if you can.
 
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