My noise problem was also solved by using balanced cables and by putting a cheap power supply from a laptop computer in a different plug. Now my HS80M are absolutely quiet, even though I added a subwoofer, and such a fun to use.

I use balanced cables with anti surge power strips which takes care of most issues but i had problems with the hs80s too. I needed to use my laptop with Arc which wouldn't have been possible cause of the noise. I had a spare psu so i replaced the plug leaving the earth disconnected and this took care of it.

I don't if you've used Arc yet but it's pretty sensitive to noise and will not do the measurement if there is 'ambient noise' so it needs to be as quiet as possible.

Oh yeah and i usually have the computer stuff on one power strip and the audio (interface, monitors etc) on another. Hth.

Little update here, got some balanced cables, the noise is still there but now it's a LOT lower. So much so that I have to listen real close to hear it when no music is playing.

So at last I can truly retire my BX5as from music production and get some serious use out of these Yammys.
Now to set up ARC.

Cool.. thanks for the info.
How much did you pay for them? I suspect that the lower quality ones won't do such a good job ... and this is often a price related issue.

They were 150kr each (Sweden), that's $22 each according to xe.com.

Thats a bit on the high side. A pair of Neutrik XLR connectors are something like $10, properly shielded balanced mic cable is like $1 per meter. Add a bit for the half hour it takes an amateur to construct and solder it. You should be able to find balanced patch cables for $10 or maybe a bit lower. And the quality should be fine. Not much can go wrong...

My 2 cents...

STOP! Before you spend money on anything try this.

This is assuming you're using a Windows Vista or 7 PC with a motherboard that uses the AWARD BIOS software!

After spending a couple of grand trying to work out what the F@#$ was causing this zipping/whining noise coming through my speakers (It damn near drove me insane) I discovered the problem was simply a setting in the BIOS of my motherboard (Gigabyte GA-EX58-UD4, and its true for a lot of motherboards using the AWARD BIOS software).

OK!

1). Switch your PC on and press the F9 key continuously until you reach the BIOS screen. (It is sometimes the F12 or Del key)

2). Navigate to "Advanced BIOS Features". Next navigate to "Advanced CPU Features".

3). Now, you should see a feature named "CPU Enhanced Halt (C1E)". If this feature is enabled, disable it and the noise should disappear; I've not only solved my noise issues, but several other victims of this phenomenon too!

This feature should be disabled by default (especially for multi-core CPU power users). The function this feature performs is "power saving" by decreasing the core frequency and voltage to the CPU when the system idles, but from my experience it appears to do this randomly, which is why, if you pay close attention to the noise when moving your mouse, the noise is interrupted and sustained again when the mouse is released (or not moved).

I stress that disabling this feature will have no adverse effect on your PC, if anything, it should also fix any "clicks and crackles" you may experience from time to time.

... And, it costs nothing to do, so give it a go!

LOU

Hey it's Sweden, everything is overpriced here. I get all the expensive stuff from Thomann in Germany.

The ones I got are 3m each. They should have had 1m cables too but they were sold out. I suppose those ones would have been around 100kr each.

Thanks for the tip. Might come in handy for someone who can't solve the problem with balanced cables. I will try it anyway myself to see if it will remove the remaining noise.

I have also a problem with my Yamaha HS monitors, but not through the laptop/pc power supply or something.

Solo(with connected to the audio interface or pc) the noise is absolutely low. But connected to my interface (TC Electronics Desktop Konnekt 6 - not bus-powered) the noise comes... changes of the power sockets or also balanced cables didn't helped

Noise still here .. but understanding what that was.. I prefer to leave it disabled. ..anyway, thanks for the tip.

So after some researching i found that there are 2 solutions.

1st is the Hum x that eliminates the ground loop safely. Lifts the ground but still protects from surges like a regular plug. I don't know much i just know there are people that like it.

http://www.youtube.com/watch?v=YyYb266R2-M



Another way is to use a ground loop isolator. I've only seen it for rca but that's what converters are for!

http://www.ebay.com/itm/GROUND-LOOP-ISOLATOR-NOISE-SUPPRESSO R-FILTER-KILLER-RCA-RCA-15-AMP-22-long-/250928099102?_trksid =p5197.m7&_trkparms=algo%3DLVI%26itu%3DUCI%26otn%3D4%26po%3D LVI%26ps%3D63%26clkid%3D6477319025005333552

Going to buy the isolator and hopefully that fixes the annoying high pitch.

I picked up a 27" iMac about a year and a half ago and had noise issues. Tried moving around things, different power strips, better power strips and could never get rid of the noise. Picked up a Hum X, plugged my iMac into it - dead silence. Strongly recommended.

Does this BIOS also comes in the intel CPU boards?