[Samsung Galaxy S8 & S8+ Cross Device Development] ace2nutzer:
@madhatter57

Did you reduce the little CPU Freq from stock value ? - Try to keep at 1690 MHz. Also check your little CPU suspend max_freq, try to keep 1690 MHz as well. And on Audio PM-QOS put 1690 MHz as well.

up_threshold value and boost on/off doesn't matter since we can set PM-QOS.

I use the original "Samsung Music" app and even if I enable all the sound improvements it still works fine with just 832 MHz. (tested with headphones, screen on/off)

Maybe you go over 0dB = distortion. Or little CPU is over 100% load.

Best way to check this is by using ADB while music is running over screen off with headphones.

e.g.

adb shell
su
top

PID USER PR NI VIRT RES SHR S[%CPU] %MEM TIME+ ARGS
3739 audioserver 20 0 102M 8.9M 4.3M S 73.3 0.2 35:36.56 audioserver
3853 mediacodec 20 0 53M 3.6M 2.5M S 8.0 0.0 34:47.50 media.codec hw/android.hardware.media.omx@1.0-service
3831 media 20 0 112M 4.7M 3.7M S 7.3 0.1 0:06.96 mediaserver
3709 audioserver 20 0 37M 3.5M 2.1M S 6.3 0.0 4:10.75 android.hardware.audio@2.0-service
23259 root 20 0 12M 4.0M 3.4M R 4.6 0.1 0:04.08 top
4014 system 18 -2 5.3G 288M 201M S 1.6 7.7 24:32.48 system_server
...

audioserver 73% with "UHQ Upscaler" + "Dolby Atmos"

PM-QOS 832 MHz = no scratching at all.

If I set 1690 MHz for PM-QOS i get only 46% load on audioserver:

PID USER PR NI VIRT RES SHR S[%CPU] %MEM TIME+ ARGS
3739 audioserver 20 0 102M 5.8M 4.1M S 46.6 0.1 44:16.54 audioserver
3853 mediacodec 20 0 53M 3.5M 2.2M S 5.0 0.0 35:47.16 media.codec hw/android.hardware.media.omx@1.0-service
3831 media 20 0 113M 4.4M 3.3M S 4.6 0.1 0:59.05 mediaserver
3709 audioserver 20 0 38M 2.9M 1.9M S 4.3 0.0 4:54.78 android.hardware.audio@2.0-service

Note if even @ 1690 MHz you get over 80% load on audioserver it's an issue with too high CPU load and therefore the only way to fix would be to use other codecs that are more efficient or to move audio stuff to the big CPU. That would work but it'll drain a lot of battery for just playing music lol.

Personally I play music with only "Tube Amp-Pro" and there is almost no load at all and works just fine without to force any higher CPU Freq for the little core. In fact it works fine with 455 MHz:

PID USER PR NI VIRT RES SHR S[%CPU] %MEM TIME+ ARGS
23452 u0_a196 20 0 6.0G 287M 221M S 13.6 7.7 0:36.88 com.sec.android.app.music
25990 root 20 0 12M 4.5M 3.6M R 6.0 0.1 0:00.43 top
23753 u0_a88 20 0 4.6G 151M 133M S 3.0 4.0 0:12.42 com.sec.android.app.soundalive
25927 system 20 0 3.7G 96M 90M S 2.0 2.5 0:00.14 com.samsung.android.lool
1512 root 0 -20 0 0 0 D 1.3 0.0 4:05.04 [cpu_dvfsd]
1118 root 0 -20 0 0 0 D 1.3 0.0 3:42.08 [gpu_dvfsd]
24000 u0_a8 20 0 4.2G 102M 98M S 1.0 2.7 0:00.32 com.samsung.android.app.aodservice:provider
2011 u0_a225 20 0 4.2G 150M 126M S 1.0 4.0 0:17.89 com.ace2nutzer.settings.g95x
4014 system 18 -2 5.3G 292M 199M S 1.0 7.8 25:31.59 system_server
22819 u0_a195 20 0 4.2G 138M 124M S 0.6 3.7 1:08.14 com.futuremark.dmandroid.application
5423 system 20 0 3.8G 112M 102M S 0.6 3.0 1:48.84 com.sec.android.sdhms
3831 media 20 0 108M 5.3M 3.2M S 0.6 0.1 1:13.57 mediaserver
3739 audioserver 20 0 105M 6.4M 4.0M S 0.6 0.1 46:18.90 audioserver

Didn't implement it so far, since it doesn't seem to be really needed.

Yes I know, you'd posted on Note8 forum, we are here on S8 forum.