[00birdy]

I'm using the 7.1 on board audio.  I notice on all 3 pairs of my headphones that I get a low buzzing noise that is always present, even if i completely mute all sound from the control panel.  It also stays at the same pitch no matter how high or low the actual volume is (obvious since muting doesn't help).  The noise seems to get more active as I go through programs or click around the internet and such.   I also just noticed that after I walked away from the computer for 10 or so minutes and came back it wasn't there, as soon as I played a track it came back immediatley.  Might be something to do with the z5500.

I currently have logitech Z-5500 surround hooked to the on-board through the orange/green/black cables. 

Here's the build, I've used high end parts for everything so it's not that.
 
Case (NZXT Tempest EVO Gaming Case)
Processor (Intel® Core™ i5 750 Processor (4x 2.66GHz/8MB L3 Cache))
Processor Cooling (CoolerMaster Hyper 212 Plus)
Memory (CORSAIR Vengeance 8GB (2 x 4GB) 240-Pin DDR3 SDRAM DDR3 1600)
Video Card (NVIDIA EVGA GeForce GTS 250 1GB)
Motherboard ([SLI] ASUS P7P55D-E PRO w/ 10-ch HD Audio, USB 3.0, S-ATA 3.0)
Power Supply (750 Watt Corsair CMPSU-750TX)
Primary Hard Drive (WD Caviar Black 1 TB HARD DRIVE 64M Cache, 7200 RPM, 6.0Gb/s)
Optical Drive (24X Dual Format/Double Layer DVD±R/±RW + CD-R/RW Drive Lightscribe Technology)
12-In-1 Internal Flash Media Card Reader/Writer
Meter Display (NZXT Sentry 2 Touch Screen Fan Controller & Temperature Display)

 

[chewy4]

It's likely due to the wiring. My front panel audio is TERRIBLE, even when plugged into my $180 soundcard, with a high pitched ringing noise always present. 
 
Either assure that all your wiring is completely shielded, which can be a total pain in the ass, or just get a dedicated soundcard. You can get one for $30 now and it's going to work better than onboard audio.
 
 
EDIT2: Ok, rereading it looks like you were using back panel ports, so it should have nothing to do with wiring... Sounds like processor interference, which I would think would also be solved by getting a soundcard...

 

[00birdy]

Quote:

It's likely due to the wiring. My front panel audio is TERRIBLE, even when plugged into my $180 soundcard, with a high pitched ringing noise always present. 
 
Either assure that all your wiring is completely shielded, which can be a total pain in the ass, or just get a dedicated soundcard. You can get one for $30 now and it's going to work better than onboard audio.
 
 
EDIT2: Ok, rereading it looks like you were using back panel ports, so it should have nothing to do with wiring... Sounds like processor interference, which I would think would also be solved by getting a soundcard...

correct on the back panel ports.  I'm also wondering if it's maybe something wrong with the z-5500 though.  I've noticed when I let sound go idle for a while it sort of turns itsself off or does something, not sure what it is.  Even if I'm using the computer the whole time but let's say I don't open or do anything that would cause a sound to be created.  Then it will tend to go more mute until it sort of kicks back on when a sound or something is finally played.  I notice this even directly through the satellite speakers when I have no headphones connected.  Might be part of the win 7 software or something though?  theres so many variables it seems.

 

[mtkversion]

Try isolating the speakers/computer by plugging them into separate grounded outlets or power strips.  I had a low level 'hum' in my speakers until I moved them to their own outlet and it went away.

 

[I3eyond]

Get a sound card with digital optical output and hook that up to your Z-5500s.  Should eliminate all computer noise.

 

[stv014]

The motherboard of the OP already has an optical S/PDIF output, so it can be tested even without a sound card.

 

[chewy4]

Yeah there should be no interference from  anything if you use the Z-5500 as your main DAC. If you can connect it via optical like others have suggested and there is still noise I would say there's something wrong with it.

 

[00birdy]

The optical from mobo to z5500 did seem to fix all of the issues.  So does that mean the 7.1 cables are the issue or what? (What are these called as the back of my z5500 says 6 channel direct but I'm not seeing too many green/orange/black cable combos for sale anywhere.  Can this be basically any common 3.5mm plug?)
 The only thing is the z-5500 only has one optical/coax/7.1, so my xbox is gonna have to get swapped out all the time with the PC one now.  and I don't think I can use the 7.1 on my xbox or bluray players.  actually the xbox is optical only. 

Ironically I hear a low hiss when my computer sound goes idle, but when I play anything back up and pause it goes away which is good.  the exact opposite of the other connection. kind of weird. If nothing is playing the display text goes right to no digital audio.   
 

currently setup is:
Bluray - digital coax - z5500
xbox - digital optical - z5500
PC - 7.1 or digital optical - z500
HDTV box - digital optical (unplugged) - z5500

 

[chewy4]

Quote:

The optical from mobo to z5500 did seem to fix all of the issues.  So does that mean the 7.1 cables are the issue or what? (What are these called as the back of my z5500 says 6 channel direct but I'm not seeing too many green/orange/black cable combos for sale anywhere.  Can this be basically any common 3.5mm plug?)
 The only thing is the z-5500 only has one optical/coax/7.1, so my xbox is gonna have to get swapped out all the time with the PC one now.  and I don't think I can use the 7.1 on my xbox or bluray players.  actually the xbox is optical only. 

Ironically I hear a low hiss when my computer sound goes idle, but when I play anything back up and pause it goes away which is good.  the exact opposite of the other connection. kind of weird. If nothing is playing the display text goes right to no digital audio.   
 

currently setup is:
Bluray - digital coax - z5500
xbox - digital optical - z5500
PC - 7.1 or digital optical - z500
HDTV box - digital optical (unplugged) - z5500

 
Not necessarilly the cables,  onboard audio can just be bad sometimes. If you're using optical you are completely bypassing the onboard DAC.
 
If you want to test if it is the cables or onboard sound, simply try plugging your headphones directly into the back panel. If the buzz is there then your onboard DAC is getting interference but the cables are probably fine.

 

[00birdy]

Yeah it's the onboard dac then.  I plugged only my headphones into the front panel and got really terrible buzzing.  I was looking at buying an AMP, so I'm thinking now that If I buy an amp that doesn't connect via optical-toslink, then I will have to buy a soundcard with a different DAC to bypass the problem?  Using RCA to my amp will probably give me the exact same problem.

If I bought a DAC/AMP in-one combo, and connected that to mobo with RCA cables, it would probably do the same thing wouldn't it?  Or would the DAC in the AMP fix that.  Whatever DAC is in my z5500 wasn't able to, as it still does the buzzing with the 3.5mm connection

 

[chewy4]

I thought using the DAC in your z5500 did solve the issue?
 
The green/black/orange cables are analog. So the z5500 wouldn't be using its digital to analog converter since the signal is already analog(unless it does some reconversion, but at any rate the noise would still be there from the original signal).
 
RCA would also be analog so the noise would be there whatever you plug them into. If you buy a DAC/Amp combo you would need to use the digital connectors(S/PDIF or USB) in order to take advantage of its DAC and get rid of the noise. Every DAC/Amp combo will have one of the two, or both. But if you bought a standalone amp and hooked it up via RCA to your mobo, yes you would still have the problem.
 
A soundcard will likely fix the noise as well.

 

[00birdy]

It goes away using the optical on the Z5500s but not using the analogs, so the dac in there didn't help that part of it.  Motherboard is to blame.  I think I'm just going to get an amp with an optical connection, maybe the audio-dg or something else, but there seem to be very few that have it under $250.  Any other good amps that come to mind let me know.