[Solved] Win 7 crackle sound, but same guest no crackle

[kesepian]

Version 6.0.8 r130520 (Qt5.9.5)
Host: Linux Mint 19.1 x64 Cinnamon
Guest (1): Windows 7 x64 (installed during Virtualbox 6)
Guest (2): Windows 7 x64 (installed during Virtualbox 5xxxx)

Yesterday was the first time I could hear crackle in Guest 1... It never happened before. I did nothing to the Guest, I did not install anything new, so it is somehow inexplicable for me.

The strange thing is that Guest 2 does not have crackle at all.
When both of my guests' sound was perfect, both had:
Host Audio Driver: Pulse Audio
Audio Controller: Intel HD Audio

Before I posted this I have searched the forum and the Internet and set my troubled guest (1, the one with crackle) to ALSA AUDIO DRIVER in the Host Audio Driver field instead of the Pulse Audio, but there is no difference.
I have attached both of the log file.

EDIT: I included BOTH logs in a ZIP archive.

[socratis]

I think an admin should modify the maximum file size since Vbox exports that kind of size file.

On the other hand, I think that a user/reported could ZIP their text files. It helps you, it helps us, it helps the server, it helps save a (virtual) tree or two...

Please do the same for the already attached log and replace the plain text one if you can...

[kesepian]

Thank you, it didn't cross my mind. Gosh, I am really ashamed.
I updated my original post and included a zip archive containing both log file. Thank you!

[mpack]

00:00:01.170602 NumCPUs <integer> = 0x0000000000000004 (4)
...
00:00:01.387386 CPUM: Physical host cores: 4

Let's try it on a VM that doesn't leave the VirtualBox host process and host OS with 0 cores. A max of 2 cores only for any VM on this host.

Yes, I'm aware that both VMs make the same blunder. Not likely to work well != guaranteed to fail.

Also make sure that neither guest is configured for 5.1 sound. Stereo should be enough, and has much lower I/O requirements.

[kesepian]

Thank you for your reply:
- I understand is not OK to use maximum cores and I now changed to 2 instead of 4.
- in my guest os (win 7) I went in Sounds - Configure - and saw Stereo already checked.

I have to admit I did not pay attention to setting a max of 2 cores and I put 3 but the crackles were present but so often as before. Then I read again your message and I see you wrote „max of 2 cores” and I set that to 2 and it seems everything is going swell!!! Thank you!
I have to mention that I have a soundcard with 4.0/ 5.1 / 7.1 capabillities cause I am seeing that in Sound Settings under Linux but I set up to 4.0.

I will let this topic unmarked as solved another 24 hours so I test it right before marking it as solved.
THANK YOU, mpack!

[socratis]

I have to mention that I have a soundcard with 4.0/ 5.1 / 7.1 capabilities cause I am seeing that in Sound Settings under Linux but I set up to 4.0.

Your physical sound card has nothing to do with the virtual sound card present in your guest OS. All the hardware in a VM is virtual, except your CPU.

[kesepian]

Thank you both for your help!
You were right! Having only 1 core instead of maximum solved my problem and everything works fine.
Subject closed.