Manual AEB-O page 6, channel routing. And what does 'I have to choose channel 9+10 to get Sound' mean exactly? Choose where? What is 9+10?

Good morning,
thank you very much for your answers.

As far as I got:

HSPE 9652
ADAT1 = Stereo Channels 1-8 (ADAT 1 to 8)
ADAT2 = Stereo Channels 9-16 (ADAT 9 to 16)
ADAT3 = Stereo Channels 17-24 (ADAT 17 to 24)

Connections on card (upper left, if you look to the front, the bracket on the left)
ADAT1 out
ADAT2 out

What I did:
wire-connection from electric ADAT1 OUT to AEB4-0

AEB4-O jumpered to use outputs 1-4, Output 1+2 connected to the speakers

In windows I see the WDM Devices as Stereo pairs (ADAT n+m).

Now, to get sound the system (youtube or anything else) I have to choose the WDM Device with stereo pair ADAT 9+10
This is strange, as I would expect to send the Application output to Stereo pair ADAT 1+2 (related to ADAT1 OUT) that is connected to the AEB4-O). ADAT 9+10 should go to ADAT2 Out, but that is not connected to AEB4-O....
No, there is no other connection to the speakers where the signal could go through somewhat "hidden" :-)

No other ADAT stereo pair brings anything to the speakers.

Does this make sense ?

-------
Was ich nicht verstehe ist, wieso am elektrischen ADAT1 output der 9652, der mit der AEB4-O Karte verbunden ist, die Adat-Kanäle 9-16 anliegen..... der Total Mix bekam einen Totalreset und zeigt auch immer schön ein Signal dort an (Playback & Output) was ich in den Windows Devices als Standard out wähle. Aber - ausgegeben an die AEB-Karte werden via elektrisch ADAT1 die Kanäle 9-10 (Wenn ich die Lautsprecher an Ausgang 3+4 hänge, ist es das ADAT Stereo paar 11+12.

There might have been early cards or firmwares where the ADAT 1/2 jumpers or the printing were swapped. Just use ADAT 2 out then...