Very very faint hum coming from Yamaha HS80M monitors

As a test, do you hear this same noise when you disconnect the audio cables from the monitors?
If so, you're probably hearing the noise-floor of the monitors' amplifiers (self noise).

Jim Roseberry


As a test, do you hear this same noise when you disconnect the audio cables from the monitors?
If so, you're probably hearing the noise-floor of the monitors' amplifiers (self noise). 

Hey Jim...


Ok I've run several test this morning and when I unplug the XLR cables running to the monitors the noise stops. This noise is definitely coming from the computer somehow when a Hard drive writes the hum stops and when I move the mouse the hum is pronounced. Also the hum is congruent with the light on my PC that symbolizes that the PC is working. My old monitors didn't have this problem and all I did was disconnect the old speakers and hook up the HS80M's with their supplied power cables...this is really strange. I've tried running the power cable from the PC to a different power outlet in another room...no change.    




Ok did a little bit more testing and hooked up the old monitors to check and now these have the hum as well....I know for certain that before last night the hum was not present. I did have to install new shelving to accommodated the new speakers and I moved my desk to install the shelving....maybe something happened with my wiring during this process? So where should I start? 

chuckebaby


you probably have a ground problem in your electrical system..go get one of those ground addapters(2 dollars) and check out the other outlets in your studio that are on different breakers.seriously..check this.also cables laying on top of eachother.
 
in short..try plugging it in to a different outlet not on the same curcuit breaker.

Thanks for the reply. Not sure how I would test on another breaker....would that be a different room? If so I've done that. And to add that I didn't have the problem yesterday. 




I did some more tests and it seem that when I unplug the firewire cable from my firewire interface the hum goes away but when I power down the firewire interface leaving the firewire cable connected the hum is still present.

Hum... the bane of musicians and recording engineers everywhere.

There are a number of things that can cause hum in circuits. You have to play detective and track it down.

Good electrical grounding is very important. That can cause hum. Since it didn't do it with the old monitors, but it does with the new ones.... and the wiring is the same..... I would assume that the issue might be in the monitors, but maybe not. Maybe they are just more susceptible to picking it up and amplifying it where the old ones were not.  Even though you unplug the inputs and it goes away.... when you plug them back in, the hum appears. The circuitry inside the monitors could very well be of lower engineering quality.... shields and grounds not complete enough to block or negate the 60hz hum from the AC line. Bad solder joints, leaky caps, all sorts of problems internal to the monitors or simply poor design of the amp circuits.

Your rig should run really quiet, so now, you need to investigate the ground issues, and power quality.

Check to be sure the circuit supplying power is properly grounded. Check if a ground lifter (one of those adapters) will make a difference. I do not recommend running it permanently on an ungrounded circuit. But check that to see if it is a ground loop as Beagle mentioned. the adapter will break the loop.

The mouse... is it wired or wireless?  RF makes noise in some machines.... as does the internal functions of the computer..... remember.... the computer has a clock in it that is running at very high frequencies..... this can translate into audible noise....especially if a component in there is bad or going bad. Power supplies can cause this too, since they handle the 60hz power and convert it to DC for the computer. A bad filter cap will let the hum get through and couple that with a poor monitor circuit design and you have a low level hum.....

So many possibilities.... let us know what you find, when you find it.