Tracking down the source of a high pitched sound at the edge of hearing - Page 1
Forum section: electronics / repair

author: cdev
author_rank: Super Contributor
timestamp: December 06, 2020, 06:53:28 pm
content: I have one of those high pitched whines coming from my PC, Its probably around 16-20 KHz judging by the characteristic that its literally right at the edge of hearing..From what Ive read in the past, its likely to be an inductor, right?Hmm, maybe I can come up with a frequency using sensors, plus Baudline or some similar FFT program (I probably have a bunch of programs that might be able to manage this)Using and a piezo button or condenser mike.Or maybe just a coil or two coils at right angles.. to pick up the magnetic field. Attached to a coil, or two coils and my scope. (that should pick up a magnetic field)Or an RF probe, since the frequncy is in the VLF range..Will try to see if that can give me some insight and attach what I can find here. .What on a motherboard could/would be causing this?

author: edpalmer42
author_rank: Super Contributor
timestamp: December 06, 2020, 07:16:57 pm
content: How old are you? If you're out of your teens, you probably aren't hearing 16 - 20 KHz.The easiest way to find a sound like that is to take a rubber or plastic hose and stick one end on your ear and go looking for the sound by moving the other end across the board right on top of the components. If you can hear the sound from a distance, it's guaranteed that you'll find it with the hose.

author: IanB
author_rank: Super Contributor
timestamp: December 06, 2020, 07:41:18 pm
content: Something to do with the video in my PC makes a high pitched sound. When I rearrange windows on my monitor there is an audible sound track. I guess it could potentially be a variation in load on the power supply, and I'm hearing a variation in the switching frequency. Or it could be something to do with the video refresh circuitry. But I would assume that many digital electronic devices with clock driven circuitry will tend to make audible noises.

author: cdev
author_rank: Super Contributor
timestamp: December 06, 2020, 07:50:59 pm
content: Ian, I get that too,and I can also see changes in the waterfall display - caused its likely by RFI on my SDRs. But thats not the same as the sound that I'm describing, although it may be caused by the same family of changes, just on the audible domain. Maybe thats the RF part of it.Quote from: IanB on December 06, 2020, 07:41:18 pmAlso, although I'm older I may still have managed to keep more high frequency hearing because I take things like NAC which help prevent hearing loss quite a bit. (n-acetyl-cysteine, preursor of glutathione- its an antioxidant and presby-(I forget the rest, so I guess I am not immune to some of the effects of aging!) aging associated hearing loss is caused by pro-oxidant changes that are response to interventions like manipulation of precursor availability )

author: cdev
author_rank: Super Contributor
timestamp: December 06, 2020, 08:13:06 pm
content: Maybe you are right but when I adjust the highest bands on my equalizer with audio programs I can tell its being adjusted. So i still have some hearing up there.Quote from: edpalmer42 on December 06, 2020, 07:16:57 pmTO make a long story short, I just cant do it that way because the sound really bothers me

author: SilverSolder
author_rank: Super Contributor
timestamp: December 06, 2020, 08:20:09 pm
content: Quote from: IanB on December 06, 2020, 07:41:18 pmGround loop issue with the audio circuitry...I've seen the same thing in some PCs. Usually curable with an external USB sound card.

author: cdev
author_rank: Super Contributor
timestamp: December 06, 2020, 08:33:28 pm
content: I shuld mention that the very high pitched sound isnt coming through or out of the audio system, its coming directly outof the computer, so it may be coming from the power supply, motherboard or video card.I think its likely the motherboard..Quote from: SilverSolder on December 06, 2020, 08:20:09 pmNo, I dont think that in my own case that its the audio card, It may be a coil.The noise goes away when the computer is off or suspended.

author: SilverSolder
author_rank: Super Contributor
timestamp: December 07, 2020, 09:29:44 pm
content: Rearranging windows on the screen means a spike of data getting moved over the bus into the video buffer - side effects of that spike in data movement is what is leaking through to the speaker.I never found a cure for it on any of the PCs that I've owned which had this problem, other than using an external USB sound card...

author: Rasz
author_rank: Super Contributor
timestamp: December 08, 2020, 03:23:23 am
content: @SilverSolder hearing interrupts and data transfers over the speakers/headphones is something we solved around 2005@cdev @IanB its called "coil whine", google will throw thousands of results under that phrase. Happens on crap hardware and top of the line GPUs. Usually the most successful solution is RMA

author: SilverSolder
author_rank: Super Contributor
timestamp: December 08, 2020, 07:01:06 pm
content: Quote from: Rasz on December 08, 2020, 03:23:23 amThe issue can still rear its ugly head if you use external audio amplifiers - ground loops / common mode effects between the external amp and the PC can be a real b!tch...

author: cdev
author_rank: Super Contributor
timestamp: December 10, 2020, 09:27:38 pm
content: Yes, I'm trying to figure out a good way to isolate the component. Its become so loud its no longer on the edge of hearing, ouch.I have a GTX-1070 video card and a quite old Gigabyte motherboard with a 6 core AMD processor. When I shut down the MB and turn it back on again, it takes some time to develop the full on whine when I turn it on. Its there but not loud at the beginning.Assuming its coil whine, would putting one of these two on a coil help, or hurtnail polish or hot glue?Another idea, maybe under clocking the video card?

author: ambrosia heart
author_rank: Regular Contributor
timestamp: December 11, 2020, 02:43:57 am
content: When I shut down the MB and turn it back on again, it takes some time to develop the full on whine when I turn it on. Its there but not loud at the beginning.Maybe ATX power supply. Borrow one from friends to exchange with yours to see if problem solve. There is some problems in ATX , causing the switching freq. to dropdown to audio freq.The high pitch must come from SMPS transformers (trans) such as main trans,standby trans and transistors drive trans.Open the ATX cover you will hear clearly.If high pitch sound comes from motherboard, CPU must be SO HOT that triggers the buzzer.Enter BIOS to change the threshold temperature by setting it higher. Also remove CPU heatsink to see if thermal compound dried.

author: Kerlin
author_rank: Regular Contributor
timestamp: December 11, 2020, 08:49:55 am
content: That sound can be quite a problem.When I was in high school I built an oscillator at that frequency in a pen with a peizo earpiece on the output.At that frequency it is directional, I took it to school and sat at the front of the class and used it to give teachers headaches.

author: jonpaul
author_rank: Super Contributor
timestamp: December 11, 2020, 11:55:53 am
content: We have seen many PC mobo, PC ATX PSU and Video cards with very bad current mode SMPS design and stability.Result is intermittent sub harmonic or current mode instability, at a sub multiple of SMPS freq, 30K...1MHz. so in the audible range.These oscillations are due to poor loop stability, and depend on the line, load.https://electronics.stackexchange.com/questions/135325/smps-what-is-current-mode-instability-aka-sub-harmonic-oscillationDuring various programs and displays the load changes dynamically so the oscillations are intermittent and changing.There is no inductor or transformer to modify for silent op.The culprit is usually poor SMPS design and test, by a Chinese mfg.VERY hard to track down and fix is in the loop stability.Check the drive pulses of the PSU , often you can sync on the oscillation.We have even seen these problems even in very costly professional audio and broadcast equipment costing 5K..25K $.From an old SMPS designer....Jon

author: cdev
author_rank: Super Contributor
timestamp: December 11, 2020, 03:38:50 pm
content: Thank you, this is what I want to try to do. Now, here is an interesting question. Previous computer SMPS was also subject to annoying whine and one day just blew up. After replacement with another power supply whine seemed much reduced, now its getting bad again. Is there any chance that this issue may be the result of a bad interaction between multiple components, bad combination of driver software and hardware, or failing component not in the power supply, but causing - perhaps it may have been the cause of the last PS failing?Its a standard PC, with an old motherboard, two not too old video cards, and a new (Corsair) power supply. The blown out power supply was a Rosewill "Green" supply.It gets better sometimes, its better, almost inaudible, when its first turned on.the motherboard is old.

author: jonpaul
author_rank: Super Contributor
timestamp: December 11, 2020, 04:11:43 pm
content: Sub harmonic osc is had to track, any load or line changes affect the control loop and the oscillation feq, ampl, etc.To exonerate the PSU, I would substitute a high quality known brand.The blowup has little to do with sub harmonic.Rather than rescue ancient WS builds with cheap Chinese PSU, we found it much easier to replace entire WS with modern HP, you can find used HP for example Elitedesk 800.Jon

author: cdev
author_rank: Super Contributor
timestamp: December 11, 2020, 09:49:30 pm
content: What do people think about using epoxy if the inductors that are whining can be identified?https://forums.tomshardware.com/threads/a-story-of-how-to-eliminate-coil-whine.3663256/

author: magic
author_rank: Super Contributor
timestamp: December 12, 2020, 03:54:08 pm
content: I blame it on piezoelectric effect in MLCCs when their DC voltage is varied.It tends to go away if you disable CPU power saving features.Same thing may occur on GPUs.

author: Mr. Scram
author_rank: Super Contributor
timestamp: December 12, 2020, 04:07:04 pm
content: Quote from: blueskull on December 12, 2020, 03:57:36 pmThere are quite a few charts which show what can be expected. Between 20 and 30 hearing loss is comparatively benign, every ten years past that means more loss than mere cumulative effects. Past 40 things really start accelerating and that's before taking damage from external sources into account.Considering the remarkably adaptive nature of our brain I'm also hesitant to draw any conclusions from self reporting. People love fooling themselves into being some kind of exception.

author: SilverSolder
author_rank: Super Contributor
timestamp: December 12, 2020, 04:30:18 pm
content: Quote from: Mr. Scram on December 12, 2020, 04:07:04 pmThankfully, most music information is sub-10KHz so the enjoyment of music and sounds doesn't go away!

author: Rasz
author_rank: Super Contributor
timestamp: December 15, 2020, 12:16:50 am
content: Quote from: cdev on December 11, 2020, 09:49:30 pmif you know exact coils why not replace them?

author: cdev
author_rank: Super Contributor
timestamp: December 15, 2020, 01:18:20 am
content: I don't know the exact source yet.. My computer is crammed in with a lot of other hardware and so when I work on it I always bring it to the kitchen table to have a bit of space. Ive been looking for a good program to use to generate a waterfall-like FFT or similar under Linux that I can use, with either a mike or a piezo disk (better higher frequency response, most likely).But, the audio subsystem has been uncooperative. Something about my audio inputs is currently broken on my Debian install and inexplicably Baudline, which has served me well in the past for this kind of thing hasnt worked when Ive tried to use it. It isnt seeing my audio inputs from the computer mike, nor from an external USB audio dongle. I have soime time tonight so maybe I'll see if I can get one of my other audio programs to help me do this.The level of noise changes quite a bit during use, sometimes its almost imperceptible, other times its really loud. It never shifts rapidly.By the way, acetylcysteine quite possibly is a good way to delay noise induced hearing loss somewhat.https://pubmed.ncbi.nlm.nih.gov/?term=acetylcysteine%20hearingQuote from: Rasz on December 15, 2020, 12:16:50 amGood question. I guess that would be what I would do if a less invasive procedure like putting some resonance damping material (maybe clear nail polish or epoxy) on the coil wasn't successful.

author: magic
author_rank: Super Contributor
timestamp: December 16, 2020, 03:45:56 pm
content: Load all CPU cores to the max and see what happens.

author: SilverSolder
author_rank: Super Contributor
timestamp: December 16, 2020, 07:29:36 pm
content: Quote from: cdev on December 15, 2020, 01:18:20 amWhen I had a motorcycle alternator rewound many years ago, the technician dipped the whole assembly in epoxy "to make sure the windings don't move around and fail again" - he was right, it still works 30 years later!

author: wraper
author_rank: Unknown
timestamp: December 16, 2020, 07:46:24 pm
content: Most likely it's not a coil whine but MLCC whine which happens way more often.https://www.murata.com/en-global/products/capacitor/ceramiccapacitor/apps/notepchttps://e2e.ti.com/blogs_/b/powerhouse/archive/2016/08/09/how-to-reduce-acoustic-noise-of-mlccs-in-power-applications

author: cdev
author_rank: Super Contributor
timestamp: December 16, 2020, 08:17:12 pm
content: Here is a new development, today and yesterday its been relatively cold and since I usually keep the house less heated than many the ambient temp has been kind of cool.. today and yesterday the whine has been almost inaudible. I wonder how adding some additional ventilation (I can do that without even cracking the case open temporarily by taping an additional 120 mm case fan to the exterior vent as an experiment.) will give that a try.

author: SilverSolder
author_rank: Super Contributor
timestamp: December 16, 2020, 09:33:56 pm
content: How about a small electret mic at the end of a stick, plugged into your scope, and probe around until the offending component is found?

author: HB9EVI
author_rank: Frequent Contributor
timestamp: December 16, 2020, 09:41:49 pm
content: I don't know why you bother with that piece. Since it's already an old board, drop it, sell it on the auction platform of your choice to the next who maybe doesn't hear it no more and get a new/second hand one.already a while ago I tried to figure out, why the DigitalDevice DVB-S2 card drops in a blocked state after 4-6 weeks on my linux server; only a restart fixed the issue. Turned out, it was the board (Asus P5Q-SE2) - even if I tried every kind of trick, new kernels, different configs, different module options, I couldn't get a hand on it.so one day threw the board on an auction platform, sold it for 50 bucks and got me an AMD board. Never heard anything from the buyer about problems, neither did my satellite card reproduce the issue on the new board

author: NiHaoMike
author_rank: Super Contributor
timestamp: December 17, 2020, 01:37:52 pm
content: Quote from: SilverSolder on December 08, 2020, 07:01:06 pmNot likely with modern amplifiers that use HDMI.

author: SilverSolder
author_rank: Super Contributor
timestamp: December 17, 2020, 09:39:25 pm
content: Quote from: NiHaoMike on December 17, 2020, 01:37:52 pmIs the signal digital with those?

author: cdev
author_rank: Super Contributor
timestamp: December 18, 2020, 03:23:25 am
content: The monitor I just got is very strange, it shows up as HDMI audio but there are no speakers and no amplifier. I wonder if it has the circuitry and could be used.

author: wraper
author_rank: Unknown
timestamp: December 18, 2020, 03:34:45 am
content: Quote from: cdev on December 18, 2020, 03:23:25 amWhat model? Many monitors have 3.5mm audio output.

author: NiHaoMike
author_rank: Super Contributor
timestamp: December 19, 2020, 02:20:40 am
content: Quote from: SilverSolder on December 17, 2020, 09:39:25 pmHDMI only supports digital signals.