Noise from mobo coming thru speakers

[smurph]

I have a new PC connected to my existing speakers, viaaudio jack at rear (on mobo), and regularly hear gentle hissing. I hear noisy static, and an intermittent whine that changes pitch depending on what's going on in the PC.
This did not happen with previous PC
How do I prevent this?

 

[carnageX]

Buy a sound card and you won't get all the interference from the other components on the board.

 

[Digerati]

IF the origin of the interference is the on-board sound, a new card will not repair the fault. It may resolve your speaker noise problem, but it is a new PC that does not work properly! Take it back! Or at least contact tech support while it is still under warranty and get a repair ticket running.

Even the most basic, entry level motherboard with basic on-board sound, there shouldn't be any interference unless something has failed, or was damaged. EMI/RFI control in personal computers (all high-speed digital electronics) has been taken pretty seriously for the last couple dozen years or so. Without it, the components inside the case will interfere with each other - not to mention every other device within 100 yards or so. That's why the FCC and its foreign counterparts regulate it (with pretty stiff fines too).

For a long time too it is common for motherboards with integrated sound to be used in PCs incorporated into stereo and home theater systems where users expect good quality digital audio. Therefore, motherboard makers have taken audio quality seriously too to ensure users get it. Unless you need the special features a card provides, most on-board sound solutions are perfectly suitable for most users - even with the best computer speakers and discriminating ears.

From a troubleshooting standpoint, it cannot be assumed your current integrated sound is the "origin" of the interference. It could be something else damaged causing the EMI/RFI that is affecting your sound. A shielding problem with the hard drive, for example, or a failing television on the other side of the wall might be causing the interference, and may affect any new card too.

Any device that "switches" rapidly back and forth can create RFI. This includes transistors and there are 100s of billions of them mounted on your motherboard, in dozens of ICs (chips). The power supply is a switching power supply. The GPU on a higher-end graphics card may have billions more transistors than your CPU.

Are you using digital or analog video? If analog (VGA, D-sub), you might "see" the buzz in the display.

Can you hear the noise through headphones plugged into the computer?

Network cards and cables are common noise culprits. Typically the $.50 cables. The crimped on connections are not high-tech or very durable. I would try another cable.

Are your speakers and your computer plugged into the same wall outlet? This can be significant because no two wall outlets have the same electrical characteristics. The resistance to ground will be slightly different due to length of wires and the connections. This creates a "difference in potential", a voltage difference which can, and often does result in electrical "noise". So ideally, your computer, monitor and speakers should all get power from the same wall outlet. And every computer user should have a AC Outlet Tester. I recommend one with a GFCI (ground fault circuit interrupt) indicator as they can be used to test bathroom and kitchen outlets too.

I always try to run my power cables up one side of my desk and my sound, video, and data cables up the other. That's an old habit when everything was analog, but still doesn't hurt.

Check all the speaker wires and cables. How old are they? Are they properly and securely connected? You cannot have a good electrical connection unless you first have a good mechanical connection. With speakers unplugged from the wall, insert and unplug the audio cables a couple times to scrape clean the electrical contacts of any dust, dander and oils. A wipe with an alcohol pad wouldn't hurt - then never touch contacts again - ever!

Make sure none of the computer's internal cables came loose during shipping.

Do your speakers and sound support a different type connection? Many computer speakers support direct digital inputs, as well as 5.1 or 7.1 discrete. Or you might even try another set of speakers.

Do you have the latest drivers? Check your motherboard's download page.

If me, since you said the noise changes as things are going on, that "suggests" something moving "might" be involved. So I might unplug a drive, or touch the center hub of a fan to see if the change in motor speeds changes the noise.

But again, no "new" computer should be making this noise. And no new computer buyer should have to buy new hardware to make it go away. So I recommend contacting tech support first.

 

[carnageX]

Just because the noise adjusts volume doesn't mean something is moving. I know my old GPU (was one of the first revisions of the GTX285's) would make a whining noise because of the capacitors used.

And if you have high quality speakers, they can pick up that extra interference that the onboard sound card produces (depending on the brand of the computer, it might not be the most high quality of parts). Using a soundcard will separate it from the motherboard components and should diminish the buzz; if its a high quality soundcard, with high quality connections and speakers, then there shouldn't be interference.

On the subject of interference from wall outlets, if a high-quality surge protector or battery backup is used, then interference is little to none.

 

[Digerati]

Just because the noise adjusts volume doesn't mean something is moving.

Ummm, please note I said, with emphasis using "" marks,

that "suggests" something moving "might" be involved

And please note that was after several paragraphs about high speed switching devices (no moving parts) that create noise.

And if you have high quality speakers, they can pick up that extra interference that the onboard sound card produces (depending on the brand of the computer, it might not be the most high quality of parts). Using a soundcard will separate it from the motherboard components and should diminish the buzz; if its a high quality soundcard, with high quality connections and speakers, then there shouldn't be interference.

If you have "high quality" speakers, they better not "pick up" (or produce) anything they are not supposed to. And there is absolutely NOTHING to prevent the card from picking up the same interference as the on-board, or that it will diminish the buzz. You got a link that shows sounds cards suppress unwanted interference where on-boards don't? 10 or 15 years ago, I might be more agreeable. But not today.

carnageX, please correct me if I am wrong, but you seem to be suggesting that a card, being "separate" and further away from the motherboard will somehow be immune or less susceptible to interference. In theory, I 100% agree - if those were the only factors.

But they are not the only factors, so in this real-world case, the theory does not hold. It is not separate, electrically, or mechanically. A sound board plugs into a socket on the motherboard. The socket is a complex mechanical connection and like ALL non-fixed (not permanently soldered) mechanical connections has the potential to introduce unwanted resistance, capacitance, inductance, and the associated reactances into the circuits - especially over time as dirt and oils affect even the best made connectors that are not environmentally sealed. Unwanted resistances can affect or help introduce interference - or the shielding of it.

Does that mean a card will introduce those unwanted influences? No. And if the contacts are kept clean and undamaged, there should never be a problem. But course with on-board, none of that is a problem because all connections are soldered and sealed in the motherboard's resin coatings.

And if the thought is a sound card is so far away from the offending device that it is not affected, we have to be realistic here. We are talking inches, if that - not feet. And all within the same metal "shield" - the cabinet.

But more importantly, and again, we don't know the source of the interference. The on-board device could just be faithfully reproducing what it is being told to reproduce. As a card would do too! And a card "might" actually be physically closer to the offending device.

If a spare card is laying around, fine. But I don't think it wise to spend money when there is nothing at this point to suggest that will fix the problem. Especially, I remind all - this is a new computer. It should be under warranty. But also today's motherboards (even entry level) are expected to be used where listening to a DVD, CD or MP3 does not sound like listening to a scratched vinyl record.

Sure, there are some advantages to a sound card - I was into audiophile electronics long before I got into computers - and that's pushing 40 years. So I appreciate true "high fidelity" distortion free sound. But this is digital not analog. And moving digital audio about is not high-tech. If all you want to do is listen with the expectation it sounds the same as the original recording, then on-board is just fine - the rest is up to the speakers (and your budget) and your ears. If you want to manipulate the sound or do your own recordings or mixing, then by all means a card is the way to go. I like M-Audio products.

But again - this is a new computer with a problem. It should be taken care of under warranty.

On the subject of interference from wall outlets, if a high-quality surge protector or battery backup is used, then interference is little to none.

I am a strong proponent for ALL computers being on a "good" UPS with AVR - automatic voltage regulation. Surge and spike protectors are little more than fancy and expensive extension cords. I agree with carnageX that these devices are helpful in blocking certain types of interference from entering via the power line. I note the ATX Form Factor standard requires our PSUs to do the same. But not all types of interference. For example, RFI can come through the air, not the wires.

But that was not the point. A S&S protector or a good UPS with AVR cannot correct an improperly wired, loose connection, or more importantly, an ungrounded outlet (OFTEN found in older homes). And of course, without a good ground, you cannot have effective interference control.

Bottom line, a card will not fix the problem. The noise may (or may not) go away, but the problem is still there. And the computer is new - it should be under warranty.

@smurph - We really need more information so we can further define and maybe identify the problem. My apologies for my part in running a bit OT.