The whining/screeching sound is definitely the microphone causing feedback (an amplification loop). This happens at the resonant frequency of the microphone and is caused by sound from the speaker being picked up by the microphone, this signal gets passed trough the amplifier, into to speaker and then back to the microphone, creating a loop. This is a common design issue in noise cancellation applications because the microphone needs to be very close to the speaker in order for cancellation of high frequencies to work. The headphone probably has a digital filter to prevent this feedback from happening under normal circumstances. The likely cause for this feedback issue would then be a change in the resonant frequency of the microphone, probably because the dust cover on the microphone was so dirty it blocked much of the sound from reaching the diaphragm, this effectively lowers the resonant frequency. If the lower frequency fall outside of the filter range, then the filter doesn't work and the feedback comes trough. If this is the cause of the issue, cleaning the dust covers should be a decent solution and otherwise removing them will likely prevent the problem from reoccurring.

Those are electret microphones. They are polarity-sensitive. A bias voltage is applied to the 'hot' terminal (relative to the shield) to power the FET inside the microphone capsule. You wired them correctly on the first try.

I tried most of the basic stuff in the video and it still happened on mine, I did solve the problem by sticking a piece of electrical tape between the mic wires which keeps them apart and this for the moment has solved the issue

I literally just got on my PC to look this exact issue up, and what do I see? I see my favorite KZfaqr just put a video up 2 minutes ago and it was right there on my home page! Thanks Vince! I'm deaf now from the screech from my headphones, but thanks!

2:15 I *think* I'm correct in saying that the microphone quality is important, because I believe how the noise cancellation works is that the microphone 'hears' the noises around you, and then that sound wave is inverted, and then played back to you through the headphones in real time (ish) and this effectively cancels out the 'noise'. So if you have a rubbish microphone, it's not fully hearing the full range of 'noise', and therefore not cancelling it. As I say, I *think* that's how it works - I may be over simplifying it (or completely wrong!)

I will bookmark this video in case my Sony headphones were to have similar behaviour. A known good set of microphones or another permanent fix would be the best solution to this problem. Keep us posted! 👍🏻

Why would you use a noise cancelling microphone (a microphone that will filter out noise) - if you want to record noise to perform active noise cancellation?

Great job Vince love watching you take apart things and fixing them ( sometimes) keep up the good work

Hey Vince, I watched this video when it came out and I also watched it today in preparation to clean my headphones because yesterday the ANC started acting up (no screeching noise, but the sound in the left cup was different and it sounded exactly like the noise it makes before it starts screeching) and I opened them up and cleaned them, using your video as a guide! The headphones definitely needed a clean and now they work as new! Thank you so much once more for the great video!!!

The problem seems to be a feedback loop. Anyone who is into playing music will know that the difference between feedback and no feedback can be very small (Jimmy Hendrix) depending on the acoustic chamber or the distance between the instrument and the amplifier. It might be that the area where the microphone sits is set to a very tight tolerance, on the edge of feed back making them very sensitive and accurate but the slightest defect and change in that area tips it over the top. In other words a design flaw. Love the channel Vince. Thank you!

Had a very similar issue with my Sony WF-1000XM3 earbuds. It was only in the right bud and only happened if I would lay on that side or pushed in on the ear tip. Two minutes into the video I took off the ear tip, pulled out a couple dog hairs that managed their way in the hole and the noise issue was fixed. Who would have thought? You gave me enough motivation to give it a look.

Cool video. Love the red mat. You reminded me that I have a set of headphones I have been meaning to fix. Typical though life gets in the way and things get forgotten. Left driver is completely dead.

Sounded like the Soup Dragon. After seeing a few reviews of the XM4's, I stuck with my XM3's, never had any issue with them, the ANC blocks the noise of airplane engines very well and anything quieter is straight up blocked. Very impressive.

The mics they used must definitely be part of the equation because the system as a whole is being calibrated with them. You could potentially recalibrate with other mics but for that you probably need some sort of development kit + expensive tools.

Interesting one vince, always amazed at the content you put out. you could of hooked up the original mic to a soundcard and then hooked up a bunch of different variations from RS Components to compare against the control mic until you ruled out the closest match to avoid potentially altering the acoustic characteristics of the original transducers.

Enjoying the red mat! Looks like a nice color.

Thanks a lot Vince!. Not only you helped me to avoid a new purchase, but also in reducing the amount of e-waste generated.

Will have to book mark this video somehow. A few years back my wife bought be a pair of these headphones for Christmas and I love them.

Awesome video, Vince! This stuff is always fascinating!

I have a pair of these headphones, Vince, and so far no screeching noise, but at least you have shown me how simple they are to pull apart. Also I have to say, seeing the guts of the machine, why are they so expensive they look exactly like any other cheap pair of headphones. I guess it's the Sony name. But I digress my grandson has a pair of cheap headphones which refuse to work so I am more confident I can pull those apart after watching your video. Also, I did not pay anywhere near 250 pounds for mine, which was just pure luck between me and the op shop. Love the video. It's always nice to watch your fix it videos. Vince, a sheer pleasure to watch. One last comment you'd think at 250 pounds plus you'd expect a pair of headphones that would last a very long time and not come with inbuilt faults.

OH MY GOSH!! Mines had the same issue but only on left side. Turns out the white microphone protector fell off, and that fixed it. I'm so freaking happy it was only that! I promise to protect it even more for now on.

Feeling kind of blue seeing your new mat, but will get used to it :) Great fix, even though I did not understand why you repaced the microphones when it seemed to be a dirt issue in the first place. Got the older model called Sony MDR-ZX750BN for many years, no issues of the same kind as the XM4 yet.

Wow great fix Vince you could of hit the nail on the head there hopefully they will stay that way 😊

I got me these headphones when I got my first "paycheck" from the company I wrote my bachelor's thesis at, to get me something nice. Never regretted it and it's just necessary now to have a relaxing train ride

Hi Vince, I actually have a set with a similar issue and I did clean them the same as you have, within a month one began to do it again, cleaned again and found the same stuff coming out. Long story short after 3 attempts a year has almost passed without an issue. I genuinely believe it’s a combination of “grease / oils from hair and also the factory flux used. A fair amount of head builds up within these and allows the leftover flux to seem to work it’s way to a corner. I’ve been told that recalibrating is required when at different altitudes as well as progressive wear from them but it’s still a shame considering the cost of them. As always, love the videos and the community we have here 👌

Typo in title. XM4, not WM4. EDIT: Now that I've actually watched the video, this actually helped me with an issue I was having with my older WH1000-XM3 headphones. I was hearing a hiss (not the screech you had, more like the static you used to get on untuned analogue tellies) on one side, turns out to have been hair between that same microphone and the speaker. Clear that out and good as new! Thanks Vince!

Very useful video I have had noise cancelling headphones that have done that in the past I thought I crushed the head phone cup as I sleep with mine on

The headphones are most likely tuned and calibrated for those particular microphones, since for the noise cancelling to be effective the signal used to generate the (reverse) noise cancelling sound must match the actual sound as closely as possible. So it was never going to be as simple as just swapping out the microphones, even if you found the exact same microphones they would not be 100% identical due to minor variances, you would still lose at least some of the noise cancelling effect.

You literary safe me $70 man) Thank you very much! I just took forceps and removed all the hair in the left ear, one of them even was on the microphone. Blew up a couple of times and cleaned up the hair and all is ok now. PS: In service center in Ukraine, change the pair of the microphones cost $70.

I'm around 500 consecutive days of use on my XM4'S and this has just started. Usually, it's when I have just set them down for a few seconds. It definitely draws the attention of my dog and cat.

Nice fix Vince!

Thanks so much. Mine started doing this about 10 days ago. Like your video, there seems to be a lot of vids regarding this problem (flaw) with these Sony's .

I'm loving the red mat vince it's calming for me for some reason 😂

I like the red mat Vince, it gives really good contrast to help see things. If you are adding the red as an affiliate link, I’ll buy one.

Thanks Vince, I’ve had this issue with my xm4s for ages now and my normal routine is to immediately open the app and turn off the noise cancelling, but I’ll definitely give them a good clean!

I have lost so many of these headphones over the years to this problem. The previous model also suffered from similar problems. There's also sometimes some bad white noise audible on one or both sides.

Great video, Vince. Thumbs up for the red mat. I thinkt that it will be a lasting fix. Someone probably used them to go running or at the gym, hence all the disgusting sweat build up.

Love the red mat!! I do miss the blue but this makes a nice change. Thanks for the great videos and cheers from the US Pacific Northwest🙂

Sony most likely do make their own microphones. these little microphone inserts are definitely polarised, as they contant a little electronic circuit inside them, usually a small transistor type device, and often capacitors with them. Using a less sensitive microphone will affect hte sound quality, but could eliminate the feedback loop being created in the noise cancelling circuit. Overall it looks like a design flaw that is causing the original fault.

@Mymatevince: Unfortunately, even in the official (but marked confidential) service manual for WH-1000XM4, the microphones are not specified beyond electret cap microphones. There are 2 on each side, 1 named FBMIC (the two you replaced) and 1 FFMIC (located inside the cover where the FBMIC is clipped to). As @gendragongfly explained very well, it's a feedback loop that is very common in these sensitive circuits. There are a bunch more components inside alongside the FFMIC, but none are stated with values or anything. There is fex a resistor marked DO NOT TOUCH resistor, can damage or render noise cancelling useless; but zero actual information... Easiest way to check if a microphone has polarity (all electret do), multimeter in continuity mode, touch one lead to the metal housing, and test both solder pads. The pad with continuity to housing, is GND 😉

Thanks for the full tutorial. I gave the right-side microphone of my XM4 a semi bath (because I only have 80% IPA for now) and the screeching noise somehow subsides. I plan to do a full bath as soon as I get 99% IPA. The back side of the microphone has turned green and icky and the microphone cover looks wet and sticky.

Having the correct component AND the polarity are both very important. Remember, noise cancelling is inverting the phase of the audio, so if you've already inverted it, there's a good chance it's not going to work.

Great fix! Thank you for helpful information!

Such microphones (Electret) come in three varieties; Omni directional, Uni directional and Noise cancelling. I suspect that you would need the Noise cancelling variety? That said, though most cover the most important audio range (50Hz-16KHz), I would think Sony have specified particular frequency ranges, dB and voltage range so it is probably difficult, if not impossible, to select an 'off-the-shelf ' compatible Vince . Electret microphones are polarity sensitive. The negative terminal is common to the outer case so it can easily be identified with your multimeter.

Interesting I had a similar issue with my galaxy bud pros didn't know what the issue was recently got a pair of soundcore Q30s by anker Interesting how a mic can affect the noise cancelling Glad you used the red mat I knew you would

Keep the red mat, ditch the yellow. Everybody has the blue, including me. Excellent video as always. TY

I have the exact same issue, thanks for the video. I really love my xm4s. Gonna give them a good bath and fingers crossed 🤞🤞🤞

Thanks so much for this video and showing the covers on the microphones itself - I thought it was a very fragile part so I did not take it apart. I'm going to try this cleaning on my pair of 1000XM4's that have developed exactly the same issue after 3,5+ years of usage. Will report back here to see if it worked.

Love the new red mat! I'll have to be sure to comment on these to get them more engagement than the yellow mat threads :D Oh, also a really interesting fix. I own a pair of these and haven't had this issue yet, so now I have something to look for.

I had a similar problem with my Sennheiser Momentum 3's (tws not over ear headphones). I found the mesh covering driver ports (the same mesh as on your microphones) had a build up of ear wax which effectively blocked the ports / microphones. Cleaning the mesh stopped the feed back/ screech which has not come back.

Considering the way active noise cancellation works; the audio between two microphones, one internal, and another external, are compared, in order to distinguish between the audio being played and ambient noise, and then the ambient noise is then inverted in phase and mixed into the audio being played, thus cancelling any ambient noise that makes it into your ears. It would make sense the system would be calibrated for a specific microphone with specific characteristics. Thus replacing the microphone would require recalibration, would most likely would require engineering equipment to do. I would guess the feedback loop is caused by the internal microphone not working correctly, thus the headphones are not properly separating ambient noise and noise being bled from whatever audio is being played back; which would be exacerbated when no audio is being played, as the only audio coming from the headphones would be the inverted audio from the internal microphone; thus, feedback loop.

Maybe try covering the solder connections with solder mask, as a build-up of moisture and dust might be conductive giving a signal feedback somehow.

It could be a pressure problem. I bought a set of after market hear pads for my Bose QC25 and it was making always this noise. Then I have changed for some will the foam visible by small holes as it works. The stock pad have holes. For the Bose, the pressure was important.

Great video vince!!

Nice fix Vince, this time you got a great victory! And when it comes to the mats, just use the yellow and red one! The blue is so boring to watch now after one has seen the other colors, hehe /L

It makes sense that sweat and dirt affects them, if you think about it, a lot of people use these at gyms, to jog/run, or even keep them for hours on end. I don't think the screeching noise will come back that soon if used normally.

This new green mat is great!

I have been waiting for a new video

I know this has nothing to do with the fix but nice fade on the hair Vince. Looks good.

I dig the new mat.

Imagine listening to sleep music like rain outside and it starts screaming in your ear lol!

I think now that you saw it was probably related to hair and dirt, you should pin a comment stating that it can be fixed temporarily by doing an isopropyl alcohol bath and cleanup; I'm assuming that it will still work until more hair, dust and dirt builds back up again, and also I'm assuming the screeching was because the build-up may have done some grounding to the microphone and so it creates a feedback loop causing it to screech that loudly.

These headphones are excellent. I've heard of the feedback issue but fortunately I haven't experienced it yet. Really good headphones for music festivals if you need to sleep. Edit: I think cleaning was the solution. I don't use my headphones during the day when it's hot out. Also, not much hair.

The yellow mat is still my favourite! To my mind Omni equates to any and uni is one. The penultimate point, you made about keeping these items out of landfill, by sharing the knowledge to service or fix them. I really hope someone will share, for everyone's sake!

My kids had a pair of XM3's each and they used them for hours every day for about 2 years. They were in a disgusting state at the end (stained foams from what looked like earwax (however it got there I dont know - the foams are a good 2 inches away from the inner ear)) and cracked / bent sliders etc but they worked perfectly for all that time. They now have XM$s each and I have XM5s and worked flawlessly all that time. Do you think the older XM3s might be worth anything for spares / repairs? Battery and all internals still faultless...

me salvaste la vida, amo estos audifonos

Worked for me.. thanks for the help..

I only purchased these because my neighbors loud music etc had been driving me crazy for months. So far I haven't had any issues with these headphones. They are fantastic if you are dealing with the same issues.

Of course it's polarity conscious. If you get it wrong, it will be completely the wrong way round. With the noise cancelling it picks up the external sound and then applies a frequency to cancel it out. If it is the wrong way round then it will do the opposite. 180 degrees out of phase. You'd need to ensure you have the correct impedance as well.

Would putting a thin plastic sheet between the outer cover and the foam inserts prevent this or affect the sound quality

If you own echo buds you'll definitely have had this screeching issue. Cleaning wax out of them usually fixes it but switching off the noise cancellation is another way. Not seen the problem with on ears before but I guess if blocked up its a bit like blocking up your ears, the pressure is messed up.

The button mics mounted on the driver cone can get wet/sweat/carhair/gross goo in/on them. My I replaced one on my 1000XM3's a year ago. Still flawless after daily use.

Vince is there 4 microphones in each pair of headphones two inside and two on the outside otherwise how do the headphones know what sounds to cancel out is the outside microphone as well as the inside ones playing up. 👍👍👍👍👍

Those electret microphones have polarity because they have one transistor inside, the case is the ground and when you look at the back side you will see that one of the pins is connected to the case. The mic in the HP should be replaced with Unidirectional one. Yup dust can mess up the noise canceling systems. To cancel the noise you have to put in the drivers the same sound but with phase turned at 180 deg acording to source, and magically they cancel each other. Too many things to say, too many words to type ... ask for aditional info 😉

I have its predecessor, and although it has decent noise cancelling and luckily isn't screeching, the head strap did break. For the price you pay, I expected a bit more robustness/longevity. And if I look at the XM4, it seems to have the exact same thin plastic head strap pieces 😬 Hopefully they fix that and the screeching in XM5?

They are HiLetgo Electret condenser microphone 52dB 6×2.2mm

uni directional = one direction of sound signal path or Mono bi directional = two directions of sound signal Path or Stereo omli direcrional = all directions !!! so i have found over the years poling on speekers is important. IE Red to Red Black To Black at both connections Speaker and amp .if you get it wrong the speeker will drive backwards And Fart.. because the suspension on a speeker cone pushes forward on a kick sound and if this reversed weird stuff happens . this was a intresting repair and just maybe. the poling is wrong on the mics you installed .its worth trying to swap the solder joints around and see what happens believe it or not on a pioneer mixer if you have forgotten a mic for a gig you can plug headphones in the mic socket wack the mic gain up and it works Cheers

Interesting fault and fix. Talking about Sony headphones and ipa, I have button type headphones, Sony MDR-EX15LP, and as they tend to get dirty from ear wax, and go silent, cleaned them with ipa and q-tips. It's just that there was some kind of "film" behind the rubber part and in front of the short "pipe", which came off and got damaged. Maybe I used too much force as I didn't know the structure, or maybe ipa softened it, I don't know. At least they work even without that film, but maybe the sound quality is not as good as originally though.

Ive got the xm4 headphones and i noticed sweat marks appearing on the fabric of mine too (mine r the grey/beige ones) so i put extra oval foam inserts in n tucked them under the leather padding, it covered the window in the left headphone but that only sees light when u remove headphones and pauses the music/youtube so im not bothered about that feature. Mine r over a year old n ive never had a problem.

Thumbs up for the Red mat 👍🏻😊

I have these headphones when mine squelch I clean the cloth cup my hand and kind of pump like creating pressure fir a few seconds and so far thus has always worked for me

A good way to clean is using an ultrasonic cleaner. To not use to much isopropyl, you could put the mics in the cap with iso and place that in an ultrasonic cleaner with water. Just enough to allow the vibrations to pass through to the mics in the bottle cap.

By far one of the best instructional videos, you guys should do a bunch more videos on other things because you absolutely get it not a lot of it yeah just straight directions and here’s how we did it perfect fix it

We have the same blue mat now!!!! :D best day ever! Theres a ghost in ur headphones mate!

I bought a Morphy Richards "return" breadmaker as my poor old Amazon one is getting a bit worn out, arrived today in good order, set it up for a new bake and started off lovely then crack, belt snapped and boy what a journey that was until I found on a video comment about why mess about dismantling this very difficult machine to dismantle, just dremel off the belt guard on the underside plastic then belt changed, just zip tie or screw or hot glue it back in place... so its done all ready for a new belt, have greased up the very dry bearings on the knead axle and hopefully a fix. Also fixed my 1930's Portass lathe, all up and running just waiting on some accessories and now have in my kitchen my soon to be fixed Startt 3d printer.

Do you usually not link the parts you sourced? I'm doing this repair for a loved one and would appreciate it.

It's gotta be happening to people with long hair who use them a lot. I'm sure if you use them a "normal" amount of time, they will work fine. If you've got long hair and use them constantly (i.e. college students in a dorm, traveling for a living, etc) and are exposing them to long hair, sweat, and dirt, you will probably run into problems.

You used noise cancelling mic inserts which are designed to only pick up sound in the immediate vicinity of the capsule (e.g. as in a close mouth mic on a headset) For the headphone (external) noise cancelling to work the mics have to pick up the ambient sounds around you, that are leaking into the earcup. The capsules you used probably picked up zero from outside of the ear cup because of their noise cancelling nature. Hence the less than stellar performance. Looking at the capsule orientation I suspect you should have used used unidirectional mics so that they picked up more from the downside of the headphone, where external sound will leak in, and less from the loudspeakers (which are at 90 degrees to the mic so off axis and attenuated) Omni capsules would pick up sound all around the capsule and outside so would not discriminate between sound leaking in and that from the local loudspeakers. All the above said these capsules are pretty robust and I strongly suspect that the real problem is cleaning and dirt/hair. All the dirt and hair, especially around the capsule, will change the mic pick up charastics. The screech is local feedback, and that is probably because the detritus in the eachphone is changing it's overall acoustic performance along with the dirt on the capsule cover and any that has got into the capsule. The small black cover itself is probably an important part of the capsule design. Dirt blocking small holes, and hair, will compromises the unidirectional performance of the capsule. This leads to local signals entering the noise cancelling circuitry (DSP) and creating the classic howl round noise. You could get some uni direction capsules and try again but I suspect that as you have removed all the detritus and cleaned everything back there will be no problems in the future. BTW these capsules are electret units and need the correct polarising polarity. The screen wire should be connected to the main body (as you did the first time) and the hot wire to the connection pad that appears to stand alone.

I'd love to have this headphones

I have some of these. The wind noise drives me mad and you have to faff with the app to enable reduction mode. I'm guessing a feedback fault by the description.

I like the Weller mat

You need to factory reset them and run calibration after a mic change. Both mics must be matched I.e. a pair from one package. Polarity is very important.

I've got a set, probably had them about a year and a half, I wear them at work in a noisy factory for 12 hours at a time 4 days a week. I've had no problems, still working fine, as other have said maybe something to do with hair, I'm completely bold, perhaps that why mine are still working fine. 😂

Hi Vince. At 5:23 video time stamp. Your data sheet tells you what polarity the speaker is wired

On the subject of noise cancelling, I watch your video's with headphones on and there is often sound from what I guess is your kitchen. it sounds like someone washing up, preparing food and people chatting. Funny really.

Hearing you say that it was triggered upon putting the cans on, I thought, "It's gotta be feedback, the cans are detecting when they're on someone's ears, then it activates the noise cancellation." Having experienced it on stages and sound systems, that definitely sounds like feedback, it has a distinctive sound similar to a sine wave from a signal generator. That's unfortunate, I'm sure Sony's engineers accounted for it (if they hadn't, that's worrying), but there must have been some edge cases where the mics/amps/speakers overcome whatever they did to counteract it.

hi vince how do i send you a link i have found the oem microphone for your headphones

Red mat for the win!

Omni = 360 Uni = approx 180 fwd facing on lateral plane, looking at how they are mounted they could be uni, but you need to know which way is fwd etc!

I had that squeal happen to mine and luckily it was still under warranty so they sent me a new one. Wouldn't it be something if that black stuff that came out was needed for the microphone working right, and by using the puddy was a bad idea.