Loud digital noise suddenly started (internal speakers and external)

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stripwax
Posts: 2
Joined: Sun Dec 29, 2019 12:51 pm

Loud digital noise suddenly started (internal speakers and external)

Post by stripwax »

Hi!
I got a second-hand joggler about 18 months ago, installed sqpos v3.03 straight away, and had mostly no problems. It was a bit unreliable (sometimes failing to boot, sometimes coming up with corrupted partition, sometimes boot but no audio or no screen or no touchscreen etx) but it seems related to PSU as it came with a non-original PSU rated for only 1.5A . I swapped for a 5v 4A PSU and been solid as a rock since.
Until yesterday...

I have pretty much had it on 24x7 for about a year, but had it switched off for a couple days. After switching back on I have the following problems.

1. On start-up, SOMETIMES, the OpenPeak boot screen is covered in grey horizontal lines, looks ghostly, partially visible or truncated. The Squeezeplay logo also similar covered in lines, but then a moment later the screen seems to reset, and then everything is ok. I can probably ignore this, but is it a sign of other problems? whereas SOMETIMES this problem does not occur at all.

2. Really really rreally loud digital noise on both internal and extearnal speaker, where the audio is being sent. In other words, if audio is being sent to external headphone socket (and internal speakers are bypassed) then there is no noise on internal speakers. Only headphones. If I unplug headphones, the music comes out of the internal speakers and so does the noise. It's not a subtle noise, it's as loud as or louder than the music. If the music is muted, the noise is still present, it's very very obvious and noticeable. It sounds like an extreme version of what you hear when an old Nokia cellphone is lying on an audio cable, but continuous, and loud. Very very much like a Geiger counter....

It also seems correlated with what's happening on the screen, to some extent. When audio is idle, I hear a burst of digital static every second in sync with the on-screen clock ticking, but if the Now Playing Screen has any scrolling text, the digital static noise seems to be in sync with the scrolling.

Is it an audio driver problem, a software problem, a hardware problem (with video? With cpu ? With audio? With power)

I've looked and searched for some answers. It seems odd that it would suddenly start happening. Setting max_cstate=2 doesn't seem to help (I haven't tried idle=poll but maybe I will?). I also found a recent thread (ubuntu disco) that suggested noise in 3.16 is not related to cstates and can be worked around somehow? (How?) And another thread that suggested that bad RF noise can be solved with a replacement PSU.

Before I do any of those things, can I sense check my observations? Is the noise I'm hearing the same kind of 'crackle' that is supposed to be resolved by the above? Is it RF? Is my DC socket on joggler loose and not connecting ground properly? (Just an idea, because if I wiggle it I can hear a soft scuffling noise, but it doesn't seem to materially affect the digital glitch noises).
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hawsey
Posts: 1995
Joined: Sun May 22, 2011 11:23 pm
Location: Northumberland

Re: Loud digital noise suddenly started (internal speakers and external)

Post by hawsey »

stripwax wrote:Hi!
I got a second-hand joggler about 18 months ago, installed sqpos v3.03 straight away, and had mostly no problems. It was a bit unreliable (sometimes failing to boot, sometimes coming up with corrupted partition, sometimes boot but no audio or no screen or no touchscreen etx) but it seems related to PSU as it came with a non-original PSU rated for only 1.5A . I swapped for a 5v 4A PSU and been solid as a rock since.
Until yesterday...

I have pretty much had it on 24x7 for about a year, but had it switched off for a couple days. After switching back on I have the following problems.

1. On start-up, SOMETIMES, the OpenPeak boot screen is covered in grey horizontal lines, looks ghostly, partially visible or truncated. The Squeezeplay logo also similar covered in lines, but then a moment later the screen seems to reset, and then everything is ok. I can probably ignore this, but is it a sign of other problems? whereas SOMETIMES this problem does not occur at all.

2. Really really rreally loud digital noise on both internal and extearnal speaker, where the audio is being sent. In other words, if audio is being sent to external headphone socket (and internal speakers are bypassed) then there is no noise on internal speakers. Only headphones. If I unplug headphones, the music comes out of the internal speakers and so does the noise. It's not a subtle noise, it's as loud as or louder than the music. If the music is muted, the noise is still present, it's very very obvious and noticeable. It sounds like an extreme version of what you hear when an old Nokia cellphone is lying on an audio cable, but continuous, and loud. Very very much like a Geiger counter....

It also seems correlated with what's happening on the screen, to some extent. When audio is idle, I hear a burst of digital static every second in sync with the on-screen clock ticking, but if the Now Playing Screen has any scrolling text, the digital static noise seems to be in sync with the scrolling.

Is it an audio driver problem, a software problem, a hardware problem (with video? With cpu ? With audio? With power)

I've looked and searched for some answers. It seems odd that it would suddenly start happening. Setting max_cstate=2 doesn't seem to help (I haven't tried idle=poll but maybe I will?). I also found a recent thread (ubuntu disco) that suggested noise in 3.16 is not related to cstates and can be worked around somehow? (How?) And another thread that suggested that bad RF noise can be solved with a replacement PSU.

Before I do any of those things, can I sense check my observations? Is the noise I'm hearing the same kind of 'crackle' that is supposed to be resolved by the above? Is it RF? Is my DC socket on joggler loose and not connecting ground properly? (Just an idea, because if I wiggle it I can hear a soft scuffling noise, but it doesn't seem to materially affect the digital glitch noises).
Hi Stripwax , welcome to the group/forum Image.
For the ghosting issue , that is normal for Jogglers don't worry about that , it usually goes after boot .
This digital noise issue has been documented but I'm unsure why for you it has just started happening , I think it was sorted early on in the builds on the Joggler .
I would first try to re install Sqp os then check .
Also you could put it on a USB memory stick and boot from that to see what difference if any you have .

Sent from my Moto G (4) using Tapatalk

Happy Joggling
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pete
Posts: 2852
Joined: Mon Aug 01, 2011 6:33 am
Location: Time Traveler

Re: Loud digital noise suddenly started (internal speakers and external)

Post by pete »

You can also utilize a USB to Sound device to bypass the audio portion of the Joggler. I have had similar issues here over the years.
- Pete

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stripwax
Posts: 2
Joined: Sun Dec 29, 2019 12:51 pm

Re: Loud digital noise suddenly started (internal speakers and external)

Post by stripwax »

Interesting indeed! Thanks for the suggestion to reflash - I did that and the problem went away.
Now, there's a couple of possible explanations (some kind of corruption of the flash memory, or some kind of bad ALSA state being saved and restored each time). Second feels more likely, but I tried lots of different kinds of ways to reset the ALSA state, with no success. So, it's actually super interesting problem. But a trivial fix, thanks for that - should have tried that first. (Of course, if it happens again, I might spend more time investigating)
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