Oh there it wraps me up Ohm cannot be allowed, ohm is the unit of resistance experienced by a current flow in a conductor.

Impedance (given in ohms for headphones) is the AC (internal) resistance of the headphones. The higher the resistance, the higher the signal voltage must be to maintain a specific current flow through the headphones.

The volume that results from this current flow depends on the efficiency of the headphones. It’s called SPL, the Beyer has, as far as I can remember, around ~90dB SPL. This is comparatively poor, so the Beyer needs some power and for this the integrated sound has to generate a certain output voltage and has to have as low impedance as possible. Yes, even amplifier circuits have an internal resistance. Often there is a problem with embedded solutions and you won’t find any data about it anywhere unless someone has measured your motherboard exactly.
Simply going through the installed sound chip is not effective, it is only part of the chain and not necessarily the decisive one.

So it only helps to test yourself. If the KH sounds too low or flat in the onboard sound, the onboard solution is not enough, then it needs to be upgraded externally or internally.