True. But, if saying it this specific way does not help, It is time to do some NEGATIVE TESTING, with someone NEW doing the testing.
Have someone else verify the Kemper output is set at -20db, for the Output with the connected cables.
And, have them test the Kemper with these two mixing boards, OR with another mixing board.
Paul, it was not for you 
And I agree with your last post.
If the Mackie can take +21 dBu it's surely not the Kempers output that is too hot. -5 dB would be totally safe, and -20 dB would be bad gain staging.
I've set the KPA to -21dB and during the auto trim process into the line6 stagescape, the mixer set the internal trim to +5dB. If i set the output of the KPA to -10dB the stagescape said the signal is way to hot. But i'm not really sure the mixer has realized the signal is line level, because of the XLR connection. The stagescape has an auto detection for all inputs normally depends on the jacks you use. I've configurated the inputs manually, but maybe there's something wrong. 
My spdif out is at -6dB and it's all fine with the audio interface. Maybe i could try to connect the KPA to the stagescape with spdif too, and check if there is any difference.
I've set the KPA to -21dB and during the auto trim process into the line6 stagescape, the mixer set the internal trim to +5dB. If i set the output of the KPA to -10dB the stagescape said the signal is way to hot. But i'm not really sure the mixer has realized the signal is line level, because of the XLR connection. The stagescape has an auto detection for all inputs normally depends on the jacks you use. I've configurated the inputs manually, but maybe there's something wrong.
My spdif out is at -6dB and it's all fine with the audio interface. Maybe i could try to connect the KPA to the stagescape with spdif too, and check if there is any difference.
That leaves the question if the gain staging in the stagescape is truly accurate.
I have my doubts about those automatic procedures.
My spdif out is at -6dB and it's all fine with the audio interface. Maybe i could try to connect the KPA to the stagescape with spdif too, and check if there is any difference.
There's no need to attenuate s/pdif.
I've set the KPA to -21dB and during the auto trim process into the line6 stagescape, the mixer set the internal trim to +5dB. If i set the output of the KPA to -10dB the stagescape said the signal is way to hot. But i'm not really sure the mixer has realized the signal is line level, because of the XLR connection. The stagescape has an auto detection for all inputs normally depends on the jacks you use. I've configurated the inputs manually, but maybe there's something wrong.
My spdif out is at -6dB and it's all fine with the audio interface. Maybe i could try to connect the KPA to the stagescape with spdif too, and check if there is any difference.
-21 plus 5 = -16
If you set the Kemper to -10db, that may be 6db too hot?
If you think it is because of the type of cable, use an XLR to 1/4" cable into the mixer,
-21 plus 5 = -16
If you set the Kemper to -10db, that may be 6db too hot?
If you think it is because of the type of cable, use an XLR to 1/4" cable into the mixer,
Yep, normally i would use 1/4" for all line ins and XLR for mics but the mixer is assembled together with XLR splitters into a 19" rack and all cable connections are fixed by another company. I've made a plan before for them which cables they should use but they have taken XLR to XLR for the complete rack. That's the reason why i've made the configuration manually. At the moment it's all fine. The sound is fantastic and i think there is no disadvantage to set the main out to -21dB.
might be a dumb post, but -21 set on my kemper main output was clipping the recording on my daw (sonar 7 with edirol/roland FA101).
suggest to turn everything down to infinite and raising gradually. you cannot miss it.......
Michael
p.s.: that's the beauty of having a potentiometer link so that one can set it on the fly
If you think it is because of the type of cable, use an XLR to 1/4" cable into the mixer,
... Or a simple unbalanced cable: easier, and same sound.
