Loud knocking noise from the engine?

Hello,

Does the noise change its frequency with engine speed?
The best way to diagnose noise is to be able to hear it. If you can upload a video with the noise it can surely help.

https://www.2carpros.com/articles/engine-noises

First thing you want to do is check the engine oil. A low oil level can make the engine create knocking or tapping noise. It can also be due to worn out valves.
If you are severely low on oil, the engine can seize.

You could also get knocking noise if the ignition timing is off and the sound you hear is the combustion of unburnt fuel.

Please let me know of any questions.
Thank you.