Why doe smy Mono channel has increased level?

I have a mono audio track that contains an audio event with a sine test tone (1000 khz, -10dBFS peak; pink channel). This track is routed to a Stereo Out (red) and Mono Out (grey). The Stereo Out shows also -10dBFS as expected. However, the Mono channel shows -7 dBFS. I don’t understand why this is happening. The pan law is set to 0dB thus that doesn’t cause this.

Using Cubase 13 Pro on Windows.

Search the forum for “Stereo Pan Law” which is the Preference causing this. You’ll find a full discussion of the topic that gets into the nuances.

Pan law should be the problem here. As I indicated in my post, I have set it to 0 dB (thus, no correction on the signal) and there is no summing on the mono bus . If there would be summing the I should have seen a 6dB increase. Moreover, I route a mono signal/track to a mono output track, thus I would expect to see no difference (since there is no panning going on)

The first output path in your Direct Routing is stereo and the next one is mono, so the signal is first “upmixed” into that stereo path (panning your mono track into the stereo out) and is then “downmixed” to mono… or so it seems…

You can test this by swapping the order of the direct outs. you should then see a difference in levels at the outputs.

You can also create a stereo track with the test generator and send that out to a stereo and mono output and play with the order to see the outcome.

What behavior do you want to experience when you mix?

Just tested. Indeed the order in the Direct Out seems to matter. If I remove stereo out then the mono track has a level equal to the mono out. If I first have the Mono and then the stereo, then the stereo is -3dB compared to the mono. Not the behaviour I would expect. Thought, the direct outs would be implemented in parallel instead of serie.

What behavior did you want in the end?

For me Equal Power seems to work the best. I feel like the panning always behaves predictably in terms of how I experience it in the room.