I think there is some latency between playing and sound, is this normal ?

The KPA has a latency of ~3.5ms, you shouldn't be able to detect that normally, it's the equivalent of sitting 4 ft from your amp, or adding 4ft between you and your speakers.

What is your signal chain into the KPA and to your speakers? Are you going through an audio interface first? Or are you directly plugged into the front of the KPA and the speakers plugged directly into the back of the unit?

You should be to update your KPA os to the latest version from the website.

Next would be to do a system restart (or even backup then reset to factory defaults, there are instructions somewhere on the forum for this). See if that helps.

Update the FW to the latest version.

Pleasure bro'

Quote from guitarnet70

Pleasure bro'

this is what it's all about, "men helping other men"

This is what fully grown male individuals do!

Quote from Jason_Gu

YEAH！ it works! after updating OS from 1.0.6 to 1.1.0 , it is OK now!
Thank you so much!

FYI: The latency has not changed since 1.06

Der war gemein....
Sorry, can't translate this...