In plain language
High frequencies fade faster than low ones over a copper run, so a crisp square edge arrives rounded. Equalisation boosts the frequencies that suffered most, restoring something the receiver can read cleanly.
It is not amplification. Amplifying a smeared signal gives you a louder smear; equalising reshapes it.
Why it matters in your setup
This is what allows a device in the middle of a chain to genuinely improve reliability rather than just passing the problem on. Equalise on the way in, re-transmit cleanly on the way out, and each half of the run is easier than the whole.
It has limits. If too much has been lost, there is nothing left to reconstruct.
What the DR HDMI 8K does with it
The DR HDMI 8K applies what the manual calls HDMI Equalevel: precise signal equalisation on both the input and the output. Combined with its repeater function that is why placing it mid-run helps, and why it can often replace a separate inline amplifier.
Need the hardware?
Open the DR HDMI 8K product page on HDfury.uk.