PC speakers amplify hardware sounds

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Hello all. Recently, my CyberAcoustics 2.1 PC speakers have been
amplifying my PC's sounds, including keyboard clicks, mouse wheel
clicking and hard drive activity. In addition I'm hearing a hum which
becomes louder when I raise the speakers' volume.

I've had these speakers with this system - which a relative built for me
- for well over a year and the problem started only in the last 2-3
months. I have not changed anything inside the computer. I have
disconnected and reconnected all cabling a couple of times. What is the
probable cause of this annoying phenomenon?


Re: PC speakers amplify hardware sounds


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Try moving the sound output cable from sound card to
speakers, away from power cords and transformers if it's
near any.  If it isn't near any, it's likely the hum is
coming from the system and the best way to minimize it is to
adjust your system's audio output levels (Windows(?) mixer
volume setttings) as high as possible if/before any clipping
results.  Thus you have set the highest SNR ratio the
current config can deliver.

Does your system use motherboard integrated audio?  That is
a common cause for higher noise levels. Any mid-grade (or
even cheaper old audio cards) can help to reduce noise.

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Ok but is it possible you lowered one or more of the
system's audio output levels in the mixer or (elsewhere but
ultimately it did lower the mixer setting)?

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Rarely the amp inside the speakers might be failing, perhaps
a burst capacitor.  A poor quality or worn out pot (volume
or balance adjust) might be a problem but not usually as

If you have a pair of headphones handy of at least
sufficient enough quality for fair audio reproduction, hook
them up direct to the audio output jack on the system to
hear if the noise is already present.

Sometimes integrated audio is more susceptible to system
induced noise.  For example if the system is at a different
load level, for example you install software running in the
background that results in a different system load, it can
change the noise level.   One way to compare the difference
would be to shut down all unnecessary background tasks and
(assuming Windows?) verify with Task Manager that the system
idle process is using practically all of the CPU time, and
compare that noise level to the noise level when the system
is nearer full load, for example running Prime95's Torture
Test or scrolling continuously up and down a webpage with a
LOT of complex animated images such as shockwave flash.

You might even find the noise that much more audible with
the headphones rather than the small amplified speakers.

Re: PC speakers amplify hardware sounds

AA wrote:
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Might seem like a pointless question but does your computer have a
microphone connected? USB camera with built-in mic?

John McGaw
[Knoxville, TN, USA]

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