To make sure your KeyLab Essential mk3 works properly, we advise you to plug your device directly on one of your computer's USB ports, and not through a USB hub.
There are 4 built-in MIDI ports in KeyLab Essential mk3.
1. KL Essential 49/61 mk3 MIDI: the standard MIDI port needed for all apps including DAWs and standalone software such as Analog Lab V. It enables MIDI communication via the USB-C port on KeyLab Essential mk3.
2. KL Essential 49/61 mk3 DINTHRU: Passes outgoing MIDI information from the host software through KeyLab Essential mk3’s 5-pin MIDI out connector. This can be useful when you want to sequence and control hardware synths with your DAW using KeyLab Essential mk3 as a MIDI interface.
3. KL Essential 49/61 mk3 MCU/HUI: Enables KeyLab Essential mk3 as a Mackie Control Universal surface via a dedicated port, to not interfere with other MIDI messages as notes or control changes. This port will only be needed in case you want to control a DAW that uses only MCU such as Cubase.
4. KL Essential 49/61 mk3 ALV: Transmits screen messages from Analog Lab V to KeyLab Essential mk3.
Note
On Windows make sure to install the MIDI Control Center's latest version for these ports to be displayed properly.
Note
Do not activate the MCU port if not necessary, since it will trigger notes when pressing the transport pads.
To activate the HUI/MCU protocol, you have to go in the Device Settings of the MIDI Control Center, and choose between Mackie, HUI, or 'Both'.
Warning
If you choose 'Both' when using Reaper, and that you set your DAW to listen to MCU only, you'll encounter some issues.
To solve this issue with Reaper, simply pick between Mackie and HUI, instead of choosing 'Both'.