Another cracking post

[gwurb]

Hi all,

I recently changed from a HAT DAC to a USB DAC. I am now hearing crackling and at times drop outs in the audio.

Here is what happens:
Play a track -> now and then hear a crack/pop & also now and then a drop out as if the raspberry pi is not keeping up

The system setup:
Raspberry Pi 3B
Transcend High Endurance 16GB microSD
Official raspberry pi PSU
Official raspberry pi 7" touch screen
USB connected SSD
USB Bluetooth dongle
Onboard WiFi OFF
Onboard Bluetooth OFF
MPD Device type USB with volume control disabled - USB DAC (Topping D10)
Bluetooth renderer on
Airplay renderer on


So far I checked the following:

Checked cpu utilisation - idle > 49%, mostly >80%
Checked Topping D10 with a Win 10 laptop, using the FLAC files stored on the raspberry pi connected SSD - works fine, no issues
Tried SoX resampling on and off, different rates and multithreading - does not appear to make a difference
USB (UAC2) fix on and off - no difference
Polarity inversion on and off - no difference
Volume normalization on and off - no difference
Buffer size tried smallest, largest, and another - no difference
Different microSD cards - no difference


The cracking happens when playing from SSD, Bluetooth and via Airplay.

It may be the power supply, or too many things plugged in to the USB ports (SSD, Bluetooth dongle, DAC). It could also be something else. What can I check before buying a new psu or only having the DAC as the only thing connected?

[Tim Curtis]

This doesn't seem normal "Checked cpu utilisation - idle > 49%, mostly >80%".

[the_bertrum]

I have found that with the volume control disabled, I need to reduce the "max ALSA volume" to ensure that I don't get any cracks and pops. I'm assuming that the cracks are in fact clipping of the audio and reducing the max ALSA volume gives the system a bit of headroom. Not sure if that's the reason, but it does work for me.

[gwurb]

This doesn't seem normal "Checked cpu utilisation - idle > 49%, mostly >80%".

Sitting there the idle is greater than 80%, up to 90% something. When I browse to something it drops. The lowest I've seen it drop was to having idle of 49% (51% utilisation).
I am using  sar -u 1 100

[gwurb]

I have found that with the volume control disabled, I need to reduce the "max ALSA volume" to ensure that I don't get any cracks and pops.  I'm assuming that the cracks are in fact clipping of the audio and reducing the max ALSA volume gives the system a bit of headroom.  Not sure if that's the reason, but it does work for me.

Thanks for that! I set it to 90 and it is a big difference; I think I may hear a crack but I am not really sure. I can play with the volume and see where the happy medium is.

My question about that:
If I am reducing ALSA volume then I am reducing bit depth, correct? Should I then be definitely upsampling? Will the upsampling occur prior to volume reducing the bit depth?

[TheOldPresbyope]

@gwurb

Putting your last post about ALSA aside for a minute, your CPU utilization seems way too high. I'm running a Khadas Tone Board, which appears to be similar to a Topping D-10, on an RPi4B+. 

top says my CPUs are 97 percent idle. Try using top or htop to find out what's eating up your CPU cycles.

Regards,
Kent

[gwurb]

@gwurb

Putting your last post about ALSA aside for a minute, your CPU utilization seems way too high. I'm running a Khadas Tone Board, which appears to be similar to a Topping D-10, on an RPi4B+. 

top says my CPUs are 97 percent idle. Try using top or htop to find out what's eating up your CPU cycles.

Regards,
Kent

It seems to be one of the renderers.

   
   

[Tim Curtis]

This doesn't seem normal "Checked cpu utilisation - idle > 49%, mostly >80%".

Sitting there the idle is greater than 80%, up to 90% something. When I browse to something it drops. The lowest I've seen it drop was to having idle of 49% (51% utilisation).
I am using  sar -u 1 100

Stats are below from quick test on a 3B with attached Pi 7" Touch and Local Display turned ON in System Config. The results suggest that there is something external to moOde causing the high CPU utilization on your system.

Code:

moOde release    = 6.5.0 2020-MM-DD
Raspbian OS    = 10.3
Linux kernel    = 4.19.102-v7+ #1295
Platform    = Pi-3B 1GB v1.2
Architecture    = armv7l (32-bit)
System uptime    = up 4 minutes
Timezone    = America/Detroit
Current time    = 2020-04-14 08:57:06

pi@rp2:~ $ moodeutl -m
CPU: 1.2 GHz | LOAD: 2% | TEMP: 45°C | RAM_USED: 31% | DISK_USED: 64% | DISK_FREE: 2.5G | FPM_POOL: 12 workers 

pi@rp2:~ $ sar -u 1 100
Linux 4.19.102-v7+ (rp2)        14/04/20        _armv7l_        (4 CPU)

08:55:06        CPU     %user     %nice   %system   %iowait    %steal     %idle
08:55:07        all      3.54      0.00      0.76     23.04      0.00     72.66
08:55:08        all      6.07      0.00      1.46     22.33      0.00     70.15
08:55:09        all      2.78      0.00      1.01     16.41      0.00     79.80
08:55:10        all      0.52      0.00      0.52      0.00      0.00     98.96
08:55:11        all      0.26      0.00      0.52      0.00      0.00     99.22
08:55:12        all      2.06      0.00      3.34      0.00      0.00     94.60
08:55:13        all      0.79      0.00      0.00      0.00      0.00     99.21
08:55:14        all      0.52      0.00      0.00      0.00      0.00     99.48
08:55:15        all      0.52      0.00      0.52      0.00      0.00     98.96
08:55:16        all      4.00      0.00      0.75     13.25      0.00     82.00
08:55:17        all      1.29      0.00      0.52      0.00      0.00     98.19
08:55:18        all      2.06      0.00      3.35      0.00      0.00     94.59
08:55:19        all      0.26      0.00      0.78      0.00      0.00     98.96
08:55:20        all      2.55      0.00      0.00      0.00      0.00     97.45
08:55:21        all      0.00      0.00      0.52      0.00      0.00     99.48
08:55:22        all      0.78      0.00      0.52      0.00      0.00     98.70
08:55:23        all      0.52      0.00      0.00      0.00      0.00     99.48
08:55:24        all      2.09      0.00      2.09      0.00      0.00     95.82
08:55:25        all      0.26      0.00      0.00      0.00      0.00     99.74
08:55:26        all      0.26      0.00      0.00      0.00      0.00     99.74
08:55:27        all      0.52      0.00      0.00      1.31      0.00     98.17
08:55:28        all      0.00      0.00      0.00      0.00      0.00    100.00
08:55:29        all      0.26      0.00      0.00      0.00      0.00     99.74
08:55:30        all      3.12      0.00      2.86      0.00      0.00     94.03
08:55:31        all      0.00      0.00      0.26      0.00      0.00     99.74
08:55:32        all      0.26      0.00      0.00      0.00      0.00     99.74
08:55:33        all      0.26      0.00      0.52      0.00      0.00     99.22
08:55:34        all      0.79      0.00      0.00      7.09      0.00     92.13
08:55:35        all      1.05      0.00      0.00      0.00      0.00     98.95
08:55:36        all      3.37      0.00      2.59      0.00      0.00     94.04
^C

[gwurb]

This doesn't seem normal "Checked cpu utilisation - idle > 49%, mostly >80%".

Sitting there the idle is greater than 80%, up to 90% something. When I browse to something it drops. The lowest I've seen it drop was to having idle of 49% (51% utilisation).
I am using  sar -u 1 100

Stats are below from quick test on a 3B with attached Pi 7" Touch and Local Display turned ON in System Config. The results suggest that there is something external to moOde causing the high CPU utilization on your system.

Code:

moOde release    = 6.5.0 2020-MM-DD
Raspbian OS    = 10.3
Linux kernel    = 4.19.102-v7+ #1295
Platform    = Pi-3B 1GB v1.2
Architecture    = armv7l (32-bit)
System uptime    = up 4 minutes
Timezone    = America/Detroit
Current time    = 2020-04-14 08:57:06

pi@rp2:~ $ moodeutl -m
CPU: 1.2 GHz | LOAD: 2% | TEMP: 45°C | RAM_USED: 31% | DISK_USED: 64% | DISK_FREE: 2.5G | FPM_POOL: 12 workers 

pi@rp2:~ $ sar -u 1 100
Linux 4.19.102-v7+ (rp2)        14/04/20        _armv7l_        (4 CPU)

08:55:06        CPU     %user     %nice   %system   %iowait    %steal     %idle
08:55:07        all      3.54      0.00      0.76     23.04      0.00     72.66
08:55:08        all      6.07      0.00      1.46     22.33      0.00     70.15
08:55:09        all      2.78      0.00      1.01     16.41      0.00     79.80
08:55:10        all      0.52      0.00      0.52      0.00      0.00     98.96
08:55:11        all      0.26      0.00      0.52      0.00      0.00     99.22
08:55:12        all      2.06      0.00      3.34      0.00      0.00     94.60
08:55:13        all      0.79      0.00      0.00      0.00      0.00     99.21
08:55:14        all      0.52      0.00      0.00      0.00      0.00     99.48
08:55:15        all      0.52      0.00      0.52      0.00      0.00     98.96
08:55:16        all      4.00      0.00      0.75     13.25      0.00     82.00
08:55:17        all      1.29      0.00      0.52      0.00      0.00     98.19
08:55:18        all      2.06      0.00      3.35      0.00      0.00     94.59
08:55:19        all      0.26      0.00      0.78      0.00      0.00     98.96
08:55:20        all      2.55      0.00      0.00      0.00      0.00     97.45
08:55:21        all      0.00      0.00      0.52      0.00      0.00     99.48
08:55:22        all      0.78      0.00      0.52      0.00      0.00     98.70
08:55:23        all      0.52      0.00      0.00      0.00      0.00     99.48
08:55:24        all      2.09      0.00      2.09      0.00      0.00     95.82
08:55:25        all      0.26      0.00      0.00      0.00      0.00     99.74
08:55:26        all      0.26      0.00      0.00      0.00      0.00     99.74
08:55:27        all      0.52      0.00      0.00      1.31      0.00     98.17
08:55:28        all      0.00      0.00      0.00      0.00      0.00    100.00
08:55:29        all      0.26      0.00      0.00      0.00      0.00     99.74
08:55:30        all      3.12      0.00      2.86      0.00      0.00     94.03
08:55:31        all      0.00      0.00      0.26      0.00      0.00     99.74
08:55:32        all      0.26      0.00      0.00      0.00      0.00     99.74
08:55:33        all      0.26      0.00      0.52      0.00      0.00     99.22
08:55:34        all      0.79      0.00      0.00      7.09      0.00     92.13
08:55:35        all      1.05      0.00      0.00      0.00      0.00     98.95
08:55:36        all      3.37      0.00      2.59      0.00      0.00     94.04
^C

Because it was showing chromium renderer I thought I should look at my Appearance settings. I had Backdrop style Animated. I changed it to Theme and now... 

23:15:51        CPU     %user     %nice   %system   %iowait    %steal     %idle
23:15:52        all      4.44      0.00      6.27      0.00      0.00     89.30
23:15:53        all      0.00      0.00      0.53      0.00      0.00     99.47
23:15:54        all      0.00      0.00      0.00      0.00      0.00    100.00
23:15:55        all      3.47      0.00      5.07      0.00      0.00     91.47
23:15:56        all      0.52      0.00      0.00      0.00      0.00     99.48
23:15:57        all      0.00      0.00      0.27      0.00      0.00     99.73
23:15:58        all      2.92      0.00      2.92      0.27      0.00     93.90
23:15:59        all      3.72      0.00      1.86      0.00      0.00     94.41
23:16:00        all      0.00      0.00      0.79      0.00      0.00     99.21
23:16:01        all      0.00      0.00      0.53      0.00      0.00     99.47
Average:        all      3.81      0.00      2.34      0.06      0.00     93.79

Edit: Maybe its not the appearance. Maybe its the touch screen? Usage seems to go up when I do something on the touchscreen? Not sure, everything I have plugged in is listed above.