strange audio humming noise under certain conditions

quartzz1

Member
Aug 11, 2018
49
2
71
Hi

I have a strange buzzing noise that sometimes comes from a laptop/subwoofer setup under certain conditions. laptop is a fujitsu lifebook a531, sub is this

https://www.amazon.co.uk/Trust-21787-Surround-Speaker-System/dp/B07643GD6Q/ref=sr_1_2

it happens under the following conditions

hum is virtually silent at subwoofer bass dial set to minimum. hum gets louder as subwoofer bass dial is turned up to halfway, hum dies down to almost nothing as sub bass dial goes to maximum

hum is made worse when an hdmi cable (2 metres long) connected to a TV is plugged into the laptops hdmi port

my gut instinct is that its to do with the laptops internal earthing. educated guess. I've just ordered a new hdmi cable, which should get here in a couple of days. but the hdmi cable I'm using at the moment isn't a cheapy

any ideas welcome..? more info can be given

The sub is still under 30 day trial so I can send it back for a replacement
 
Last edited:

UsandThem

Elite Member
May 4, 2000
16,068
7,382
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Do you have other speakers that you can test? If so, and they don't display the same issues, it's likely the problem is with your new speakers (which I've never even heard of before).

In fact, since you've been here, I have not recognized any the companies you have linked to on Ebay or Amazon. Maybe it would be less headaches for you going with known brands? Just a suggestion.....
 
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corkyg

Elite Member | Peripherals
Super Moderator
Mar 4, 2000
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Welcome to the mysterious world of EMI.
 

quartzz1

Member
Aug 11, 2018
49
2
71
thanks Usandthem, I'm going to try a 30 day replacement sub see if the same thing happens

Isnt it corky...the same thing happens on a different laptop, so either both laptops have the same earthing...thing....or its not that. I've also ordered a vga to hdmi converter, to see if it happens when the vga, instead of hdmi is used