Ive noticed that when the audio doesnt play, the refresh rate change happens a few seconds after the video starts. It should do this right at the beginning. Not sure if this gives any clues.
This could indicate a bottle neck in data transmission. A slow cable is often the issue. So check the HDMI standard of your cable. It should be conform to HDMI 2.0 or 2.1 to handle video AND high speed audio.
The smallest increments of adjustment is 10, it doesn't go any lower than that. I have it set to 10 but it is still too much.
You'll set the sum of volume steps, so increase that value.
You can try, but I don't think so. Better check whether reboot is running.
In your first post you mentioned an x86 installation of LE, and a non-working sound card. Is this the setup we talk about?
1. I don't know any EQ / DSP software for LE. DSP action is usually done by external hardware (AVR or dedicated DSP processor).
2. Frequency splitting is usually done by the subwoofer (serial connection), or by the AVR (parallel connection). Not by LE.
Forget about software DSP. Use a HiFiBerry DAC with DSP processor. Something like this.
Next little challenge is getting passthrough to work, but this would only be kind of nice to have.
Many audio cards are supported, but maybe not yours. I think we have to see a log...
running LibreELEC 9.2.1
Please install the latest LE from scratch (currently 10.0.2, don't try to update from 9.2.x). We don't support outdated versions.
that is, there are no differences in hardware?
Please google that. 
Thread moved to Allwinner sub-forum.
Can the rpi do full HBR pass thru to act receiver.
HBR ...
Please clarify the question. What do you want to do?
I also have an RPi 3B+ and did a fresh installation of v10.0.2. However, this latest version can not play x265 videos and even some x264 files. Later I gave up and downgrade to v9.2.8. I guess RPi 3B+'s hardware is just not powerful enough for v10.0.2. There are some other threads discussing about this already.
https://wiki.libreelec.tv/hardware/raspberry-pi#hevc-on-libreelec-9.x-10.x-11.x
JSON-RPC or kodi-send. Click!
I use several script calls in the Power Menu, and they often include kodi-send command, and everything works exactly as expected. There is no reason why something in the Power Menu should work differently than in other menus. The Power Menu is just like any other menu, the only thing that makes it "Power" is that it uses Kodi commands to control the status of Kodi and power status of the system.
Thanks for this! In that case it would help to see a log.
That's already part of my theory. I believe that all entries inside power menu will stop the kodi process.
Use other commands, like shutdown, poweroff or reboot.
PS: If you wish to interrupt the shutdown procedure, because a download is still active, you have to restart the kodi process.
Probably the kodi process gets terminated before your script content is called. So avoid kodi-send on this stage of shutdown.
You can try to copy & paste wget / busybox from Raspberry Pi OS (64 bit) to LE. There is some compatibility.
What are the odds of hdr being included for x86 by default in le11?
It's on the list, but the right guys currently have no time.
