When you create a “Stereo with Bass Management” layout, you must add the monitors detected on the network below the subwoofer to which they are physically connected.
MA 1 performs various logic checks at this point, and only when all settings are correct can you press the Continue button to proceed to the next step. If something is incorrect, it will be displayed along with a red exclamation point at the bottom of the screen.
A common error message is “! Internal bass management requires all speakers to be connected to a subwoofer or to be in digital input mode.”
That happens because all the monitors and subwoofers at the top level of the monitors found on the network have been selected.
However, during configuration of the layout, the software expects that monitors physically connected to the subwoofer will also be added in MA 1 below the subwoofer.
Please uncheck both connected Monitors first on the Layout Page.
Click [+] below the subwoofer and choose "Network-enabled loudspeaker connections".
Then ADD the Monitors from the list so they are connected to the subwoofer.
Once the interface and connection types have been set correctly and all settings are as required, the warning messages at the bottom disappear and the “Continue” button is no longer grayed out. You can now proceed to the next step.
You might be wondering why you can also select the monitors at the top level—and why that could lead to an error. The reason is that multichannel layouts have different levels, and in this case, the monitors must be selected at the top level if they are connected directly to the audio interface rather than to the subwoofer.