I've just put together a new system with a Ryzen 2600, Gigabyte B450M DS3H motherboard, 2x4GB Ripjaws 4 memory, Samsung 970 Evo, and running Ubuntu 18.04.1
I connected the motherboard buzzer and as well as doing the normal high pitched single beep at boot, it does a second lower pitched and slightly longer beep - seems to be about when the kernel boots. It doesn't do this beep when I boot memtestx86+ off a USB stick so I think it's from Linux rather than the UEFI.
Any ideas on what is going on? And how do I stop it - apart from unplugging the buzzer
The case has a laser bright blue power LED on top that I've unplugged so having the single beep on power on is nice, but the 2nd beep sounds like some alarm noise and is a little disconcerting.