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Static / buzzing from speakers at low volumes

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The111
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Default Static / buzzing from speakers at low volumes

I just started playing a few games on this Nexus 7, and I turned the volume down to the lowest setting because it is late at night and other people in my house are sleeping. I immediately noticed a soft but very audible static buzz coming from the speakers... about the same volume as the audio itself. I held my ear up to the hardware and confirmed it is both top and bottom speakers.

Anybody else experience this?
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smurfqq
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I didn't notice at first. Noticed this morning with audio low as well.

I'd like to know if anyone else has this too. Kinda wanna know if its hardware since I purchased at best buy and only have 2 weeks to return.
 
Artood2s
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Yup, I was going to report this too, but since it only occurs at minimal volume I didn't bother. I lost my good headphones so I can test the audio jack. Does it happen to you with them on too?

Btw- if this the trade off with the fantastic (for tablet speakers) surround sound I'll take it. Watch the test video on the Play Videos app.

Sent from my Nexus 7
 
tweaked
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I don't hear it. on mine. But My hearing is horked.
*Phone: Nexus 4 16g.
*Recovery: Koush touch 6.0.X
*Rom: ParanoidAndroid 4.3
*Kernel: Franco Kernel

*Tablet Nexus 7 Flo 16g
*Recovery: TWRP 2.6
*Rom: Paranoid Android
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***Flo - http://goo.im/devs/paranoidandroid/roms/flo
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siraltus
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It's because the Nexus 7 uses a crappy digital volume control that simply reduces the volume of the digital waveform before it hits the DAC, instead of having a real analog volume control -an op-amp that adjusts the volume of the signal before it hits the headphone/speaker amplifier.

What you're hearing is quantization noise as at the lowest volume the audio uses only 2-4 bits of dynamic range instead of the full 16 (or 24, dunno what DAC is in this thing). It's the same as the bit-crushing effect you hear in some dubstep and other electronic music that degrades the audio into a robotic crunchy mess, only here it's not on purpose, it's just cheap design.

There is nothing you can do about it.
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mrmartin86
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I've also noticed this (at first I was like, WTF? Is it raining in my game?). If what was said above is true, that makes me sad that nothing can be done about it.
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smurfqq
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Quote:
Originally Posted by siraltus View Post
It's because the Nexus 7 uses a crappy digital volume control that simply reduces the volume of the digital waveform before it hits the DAC, instead of having a real analog volume control -an op-amp that adjusts the volume of the signal before it hits the headphone/speaker amplifier.

What you're hearing is quantization noise as at the lowest volume the audio uses only 2-4 bits of dynamic range instead of the full 16 (or 24, dunno what DAC is in this thing). It's the same as the bit-crushing effect you hear in some dubstep and other electronic music that degrades the audio into a robotic crunchy mess, only here it's not on purpose, it's just cheap design.

There is nothing you can do about it.
I'm not sure how you know that but if you're right I guess that means it would happen on all of them... which.. sucks.. Is there anyone that doesn't have this issue to disprove this?
 
siraltus
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Originally Posted by smurfqq View Post
I'm not sure how you know that but if you're right I guess that means it would happen on all of them... which.. sucks.. Is there anyone that doesn't have this issue to disprove this?
I'm a professional audio engineer, I know exactly how these things work. Most cheap devices do volume controls that way, because adding a dedicated op-amp for analog volume control increases costs of the device, and the Nexus 7 is a budget device.

It does happen on mine, too, in every app that plays sound.
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jayochs
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I love when pros come in here and give the technical explanation haha hats off to you, sir!

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The111
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Quote:
Originally Posted by siraltus View Post
It's because the Nexus 7 uses a crappy digital volume control that simply reduces the volume of the digital waveform before it hits the DAC, instead of having a real analog volume control -an op-amp that adjusts the volume of the signal before it hits the headphone/speaker amplifier.
As the others have said, thanks for the explanation. Nice to hear from somebody who understands it, and if the problem is present in all units that actually makes me feel better since I don't have to worry about returning my otherwise perfect unit.

Question though, how come I don't hear the static when using headphones, even on the lowest volume settings where I hear the static from the built-in speakers? That makes me think it's related to the speakers and not the audio hardware... but you obviously know more than me on this.

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