Static / buzzing from speakers at low volumes

The111 · Jul 29, 2013

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?

smurfqq · Jul 29, 2013

copyists sorpeno

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 · Jul 29, 2013

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 · Jul 29, 2013

I don't hear it. on mine. But My hearing is horked.

siraltus · Jul 29, 2013

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.

ShimaMiku · Jul 29, 2013

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.

smurfqq · Jul 29, 2013

siraltus said:
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 · Jul 29, 2013

smurfqq said:
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.

jayochs · Jul 29, 2013

I love when pros come in here and give the technical explanation haha hats off to you, sir!

Sent from my Samsung Galaxy S4 using Tapatalk 4 Beta

The111 · Jul 29, 2013

siraltus said:
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.

The111 · Jul 29, 2013

mrmartin86 said:
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.

Yeah, funny thing is the first game I played was Bad Piggies on some levels with an ocean tide moving back and forth at the bottom of the screen. I thought the static was the tide sounds... until I heard it in another game too.

The111 · Jul 29, 2013

tweaked said:
I don't hear it. on mine. But My hearing is horked.

It only happens at the absolute lowest volume setting... i.e. one notch up from muted. It sort of happens at the next notch up too, but is most noticeable at the quietest setting, and you need to be in a quiet room. I only noticed because I was using the device in a small echoey mostly tile room (you can probably guess where) and because of the room having such acoustics I put the device on the lowest setting just above mute.

TheCIScommander · Jul 29, 2013

Had something like this on my original nexus 7

Except it happened regardless of the volume setting. Wasn't that audible- had to put my ear against the speaker to really hear it, but it did interfere with other devices, such as my radio, or keyboard with a head phone jack. It would make a sound like a quick DUH-DUH-DUH-DUH-DUH-DUH...DUH-DUH-DUH-DUH-DUH-DUH. My nexus 4 can sometimes cause static interference with other devices, too. Haven't gotten the new nexus 7 so I cannot say whether or not my new one has this issue

smurfqq · Jul 30, 2013

Well.. mine's not only happening at the lowest volume notch. If I put it to my ear (never actually going to do this for normal use) it's there at every volume level, just hard to hear once whatever I'm playing gets loud enough. The display unit at a local best buy does the same. I can hear it in a quiet room at the first couple notches (normal use), which is annoying. Also, since someone asked - No it doesn't happen through headphones.

siraltus · Jul 30, 2013

The111 said:
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.

My pleasure! There's tons of FUD on XDA about many things, so I try to contribute on stuff I know well to reduce that.

Without looking at the schematics of the thing I can only guess:

The speaker amplifier is probably just a simple design that outputs 100% power all the time, so you have to control the volume of the signal that enters it, whereas the headphone amp probably has an integrated analog volume control.

A volume control is much easier (read: cheaper) to do in an integrated chip with low power signals (headphone out) than higher power (speaker out), and again, cheaper was the way to go with the Nexus 7.

Hence, there are two separate outputs from the audio chip - one that feeds the speaker amplifier and uses the bit-crushing digital volume control, the other outputs full-scale audio to the headphone amplifier which controls the volume in analog.

The111 · Jul 30, 2013

siraltus said:
My pleasure! There's tons of FUD on XDA about many things, so I try to contribute on stuff I know well to reduce that.

Without looking at the schematics of the thing I can only guess:

The speaker amplifier is probably just a simple design that outputs 100% power all the time, so you have to control the volume of the signal that enters it, whereas the headphone amp probably has an integrated analog volume control.

A volume control is much easier (read: cheaper) to do in an integrated chip with low power signals (headphone out) than higher power (speaker out), and again, cheaper was the way to go with the Nexus 7.

Hence, there are two separate outputs from the audio chip - one that feeds the speaker amplifier and uses the bit-crushing digital volume control, the other outputs full-scale audio to the headphone amplifier which controls the volume in analog.

Makes sense. Thanks again.

paxunix · Jul 30, 2013

siraltus said:
My pleasure! There's tons of FUD on XDA about many things, so I try to contribute on stuff I know well to reduce that.

Without looking at the schematics of the thing I can only guess:

The speaker amplifier is probably just a simple design that outputs 100% power all the time, so you have to control the volume of the signal that enters it, whereas the headphone amp probably has an integrated analog volume control.

A volume control is much easier (read: cheaper) to do in an integrated chip with low power signals (headphone out) than higher power (speaker out), and again, cheaper was the way to go with the Nexus 7.

Hence, there are two separate outputs from the audio chip - one that feeds the speaker amplifier and uses the bit-crushing digital volume control, the other outputs full-scale audio to the headphone amplifier which controls the volume in analog.

Is this something they can fix (or at least mitigate) in a software update?

siraltus · Jul 30, 2013

paxunix said:
Is this something they can fix (or at least mitigate) in a software update?

No, this is how the hardware is designed.

Lawlbringer · Jul 30, 2013

Noticed this too from the speakers regardless of volume, and regardless of what is playing audio. It's a high pitched squeal to my ears which I can't stand. I've thrown out computer power supplies and video cards that have made similar(obviously, louder) noises.

Was hoping it could be something improved in software, but I guess not. Time to sell this.

Lawlbringer · Jul 31, 2013

http://youtu.be/c9aQnuOrTY8

Recorded what it sounds like at lower volumes with a small condenser mic next to it. Let me know if that's similar to what you guys are hearing too.

Static / buzzing from speakers at low volumes

Senior Member

Member

Senior Member

Senior Member

Senior Member

Senior Member

Member

Senior Member

Senior Member

Senior Member

Senior Member

Senior Member

Member

Member

Senior Member

Senior Member

New member

Senior Member

Member

Member

Similar threads

Top Liked Posts