Author Topic: Wired headphones. Faint buzzing/scratching noises  (Read 2721 times)

Lyall Pearce

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Wired headphones. Faint buzzing/scratching noises
« on: March 23, 2018, 08:23:16 pm »
Has anyone tried the ancient and venerable technology of wired earphones?

Do you hear faint intermittent 'buzzing' and 'scratching', apparently when cpu is being used, because it becomes more pronounced when scrolling, particularly using the touch screen.

Another way of describing the sound is like dust on a vinyl record during a silent part.

Using keys to scroll still makes the sound but after the key 'bip' sound.

Using bluetooth headsets don't make this soft sound.

I tried turning off both WiFi and Bluetooth to see if that made a difference, none.

When actually playing something, in my case Audible audiobooks, you can't hear the sounds then, stopping playback then I hear faint noises. As you know, Audiobooks are simply spoken so there is lots of silent parts in which the sounds are not audible.

Whilst on the faint sound, has anyone noticed that pressing a key causes the key sound to be played, sometimes, multiple times, terminating the previously started sound, as though the internal debounce mechanism is firing off the sound for each bounce? So, instead of a 'bip', it's sort of like 'b b bip'.

This is under stock android, in case anyone is asking.

Edit: it appears the 'crackling' lessens once the display turns off. Tap the on key so the display lights up, the crackling resumes, once the display goes black again, the crackling becomes very faint, pulsing every second. And no, it's not my heartbeat
« Last Edit: March 23, 2018, 09:12:03 pm by Lyall Pearce »
...Lyall

hiltonzola

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Wired headphones. Faint buzzing/scratching noises
« Reply #1 on: March 27, 2018, 04:56:42 am »
Based on an identical fault with my Dell XPS13 9350 my money would be on a power saving feature turning off some noise suppression circuitry in the sound device.

I posted about this previously (but not very helpfully) but this time I'll add a useful link:

https://wiki.archlinux.org/index.php/Dell_X...sing_headphones

Which may be helpful for linux users but turning off that power saving may reduce battery life.

Don't have my Gemini yet so can't confirm but I'll want to get this sorted as soon as I do.

HZ

geomannie

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Wired headphones. Faint buzzing/scratching noises
« Reply #2 on: April 01, 2018, 02:10:02 pm »
Yup, same "feature" on my Gemini. I have not tried to track it down and its not too worrying. As you say, you don't seem to hear it when playing audio.

Cheers


Quote from: Lyall Pearce
Has anyone tried the ancient and venerable technology of wired earphones?

Do you hear faint intermittent 'buzzing' and 'scratching', apparently when cpu is being used, because it becomes more pronounced when scrolling, particularly using the touch screen.

Another way of describing the sound is like dust on a vinyl record during a silent part.

Using keys to scroll still makes the sound but after the key 'bip' sound.

Using bluetooth headsets don't make this soft sound.

I tried turning off both WiFi and Bluetooth to see if that made a difference, none.

When actually playing something, in my case Audible audiobooks, you can't hear the sounds then, stopping playback then I hear faint noises. As you know, Audiobooks are simply spoken so there is lots of silent parts in which the sounds are not audible.

Whilst on the faint sound, has anyone noticed that pressing a key causes the key sound to be played, sometimes, multiple times, terminating the previously started sound, as though the internal debounce mechanism is firing off the sound for each bounce? So, instead of a 'bip', it's sort of like 'b b bip'.

This is under stock android, in case anyone is asking.

Edit: it appears the 'crackling' lessens once the display turns off. Tap the on key so the display lights up, the crackling resumes, once the display goes black again, the crackling becomes very faint, pulsing every second. And no, it's not my heartbeat

vader

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Wired headphones. Faint buzzing/scratching noises
« Reply #3 on: April 01, 2018, 08:14:07 pm »
Appologies in advance for the technobabble.......

The noise you are hearing (include me in this) is what is called crosstalk. The audio out consists of two stages - the d/a and the amp. The mixer is before the d/a so we can ignore this. The d/a (digital to analogue) converts the values of a waveform into a form we can hear. From there it is amplified so that it can be used by headphones to create sound. The output from a d/a is normall low power to preserve quality which is why it needs to be amplified. The d/a output can be turned off by tri stating it (imagine just disconnecting it from the amplifier). If the amplifier is still on, and there is no signal coming in, it will amplify what is has. The input to the amplifier now acts as an antenna, picking up electrical signals from the board it is on. The cracks and whistles you hear are the electrical signals generated by the device. The screen uses a lot of power and hence produces the largest signals. The normal solution is to turn power off to the amplifier as well, so no crackling is heard. This can have other consequences though, as the amplifier may take a finite time to turn on meaning a short sound can be lost.

It is a fine line between losing a sound and hearing crackling when not playing anything. We had the same problem in a board we were designing. We chose the same solution, crackling over loss of sound.

Hope this helps, and sorry for all the tech stuff.

PS. The reason you dont hear noise when playing sounds is that the d/a is a much stronger signal than the noise, and the reason to tristate the d/a is to minimise power use.
« Last Edit: April 01, 2018, 08:23:42 pm by vader »

Rahab D

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Wired headphones. Faint buzzing/scratching noises
« Reply #4 on: April 02, 2018, 04:47:00 am »
Interesting, Vader!
Sorry ... from the height of my ignorance, I try to understand ...
So it's like saying that the crackling having a contiguous screen is a guarantee of good sound?
What is the other choice: to sacrifice the sound quality to cancel the crackling or ... redesign the device?
Why does it not happen in other devices? Do they have less power?

vader

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Wired headphones. Faint buzzing/scratching noises
« Reply #5 on: April 02, 2018, 05:53:22 am »
Quote from: Rahab D
Interesting, Vader!
Sorry ... from the height of my ignorance, I try to understand ...
So it's like saying that the crackling having a contiguous screen is a guarantee of good sound?
What is the other choice: to sacrifice the sound quality to cancel the crackling or ... redesign the device?
Why does it not happen in other devices? Do they have less power?

It is like plugging an electric guitar in. When it is plugged in and working you dont hear buzzing, but if you take the cord out and touch one contact you get a loud buzz. That it you acting like an antenna and picking up the 50Hz from power lines. The same thing happens when the d/a turns off. I dont know if the gemini has the hardware control to turn off the amp. The speakers power down, so maybe the headphones can too. The problem is short sounds can be lost if the amp takes to long to power up. If you have headphones in, you are normally listening to music etc. There wont be any noise then - only when the music stops.

mitsugucci

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Wired headphones. Faint buzzing/scratching noises
« Reply #6 on: May 10, 2018, 03:24:20 am »
Hi!

I’ve received my Gemini yesterday and I found the same issue.
However I found the provisional solution about it.

I installed noise generator app from Play Store.
(for example, White Noise Plus)

1) Open the app and play white noise with “zero” volume.

2) Select “Play Over Other Sound” in App Settings.

3) Kill all notification of this app.


It’s so comfortable for me!
Of course you will!


Thank you for reading.
From Japan with love
« Last Edit: May 10, 2018, 03:41:01 am by mitsugucci »

Varti

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Wired headphones. Faint buzzing/scratching noises
« Reply #7 on: May 10, 2018, 04:19:08 am »
Quote from: mitsugucci
I’ve received my Gemini yesterday and I found the same issue.
However I found the provisional solution about it.
Hi and welcome!

You have found an interesting solution. If I understood well, you let it play the random noise all the time with volume set to zero? If so, is it possible to automatically run this app with the same settings every time you boot Android?

Varti
Planet Gemini PDA WiFi/LTE with Mediatek x27
SL-C1000 running Arch Linux ARM May2017, K30225 Wi-Fi CF Card, 64GB SDXC card
and many other Zauruses!

zevv

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Wired headphones. Faint buzzing/scratching noises
« Reply #8 on: May 10, 2018, 06:57:47 am »
Quote from: mitsugucci
It’s so comfortable for me!

Beware this might have implications for battery use: the noise generator is continuously generating silence to keep the audio circuitry alive, but will also prevent the CPU to enter low power state for longer time.

mitsugucci

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Wired headphones. Faint buzzing/scratching noises
« Reply #9 on: May 11, 2018, 12:00:38 am »
Quote from: Varti
Quote from: mitsugucci
I’ve received my Gemini yesterday and I found the same issue.
However I found the provisional solution about it.
Hi and welcome!

You have found an interesting solution. If I understood well, you let it play the random noise all the time with volume set to zero? If so, is it possible to automatically run this app with the same settings every time you boot Android?

Varti


Hi,

Unfortunately, it's not possible to run automatically when reboot.
But it keeps the same setting.
You should press "play" button manually.

mitsugucci

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Wired headphones. Faint buzzing/scratching noises
« Reply #10 on: May 11, 2018, 12:11:20 am »
Quote from: zevv
Quote from: mitsugucci
It’s so comfortable for me!

Beware this might have implications for battery use: the noise generator is continuously generating silence to keep the audio circuitry alive, but will also prevent the CPU to enter low power state for longer time.


Yes. You're right.
This is just a temporary solution until the manufacturer fixes this issue.

If this noise generator only works when wired headphone plugs in, it will better than now for battery life.
Of course this is not a complete solution yet.

I wish the Planet computer fixes this specific issue perfectly.