[PLUG] Buzzing speakers

[Galen Seitz]

On 3/25/20 9:17 AM, Michael Barnes wrote:
> On Wed, Mar 25, 2020 at 8:51 AM Michael Barnes <barnmichael at gmail.com>
> wrote:
>>
>> Model is VS-2121. The sound is not random. It happens at exactly :29 and
>> :59. It is not quiet, either. We can hear it pretty much throughout the
>> house, so it's not like something that has been there all along and just
>> wasn't heard over ambient noise. It is more of a sound than noise, a low
>> frequency rumble, but not like static type noise as you would get from AC
>> hum or failing components. More like hitting the bottom note or bass pedal
>> on a keyboard (musical keyboard, not computer keyboard). I'm not sure of
>> whether it is coming from all speakers or just the sub-woofer, as I have
>> not been at the computer when it happens. The computer is in my wife's
>> hobby room. It is not used that much, only for email and occasional web
>> surfing. Interesting that the on/off switch doesn't really turn it off. As
>> I plug/unplug it, the subwoofer pops.
>>
>> Thanks for everyone's comments.
>>
>> Michael
>>
>> Well, it is not the computer. I turned the computer and monitor of and sat
> there at the appointed time. It seems to be a power line issue. The sound
> is coming from the subwoofer, although I had the speakers turned off. Next
> chance I get to sit there at that time, I'll turn them on. I guess the next
> thing is to see if it is only that breaker circuit. I have no idea what I
> have in the house that would do something on the power precisely at those
> times.

Good idea to run a test with the computer turned off.  That's useful info.

It certainly seems that power line noise is a potential culprit.  If you 
have a spare UPS sitting around, it would be interesting to see if the 
noise occurs when the speakers are powered by the UPS, but the UPS is 
unplugged from the wall, and the speakers are not connected to the 
computer.  I.e., turn your speakers into battery powered speakers that 
are isolated from line power and the computer, and listen to the results.

What's interesting to me is that you indicated that this is a recent 
problem.  This suggests one of two possibilities:

1. A new, and very periodic noise source has been introduced into the 
speakers environment.

2. The noise source has always been there, but a component failure in 
the speakers has caused the noise to become noticeable.

galen
-- 
Galen Seitz
galens at seitzassoc.com