Well now you have gone full circle. What's the point of having a Kemper if you are going to mic it again?
The Kemper as is provides a Mic'd sound which you can send directly to the PA. That seems to be what y'all are after. Then just use a FRFR and you don't have a problem. You get the same sound through your FRFR solution as through the PA (no you won't but good enough).
The next thing that happened was that people felt they missed the amp-in-the-room feeling. The Kabinet/Kone solves this. It is pointless to mic this when you can just send the fully treated, with cab and everything, signal to the PA. The Kone/Kabinet isn't for that. It is to create an enjoyable, amp-in-the-room experience.
Also note that it was never possible to mic an amp the old school way and get what you are asking. It simply cannot be done. If you had your Marshall with you and used it as monitor, with a mic picking up sound for the PA, you would have two vastly different sounds standing in front of your cab and coming from the PA.
If you want the same sound from your monitor as to the audience, there are a few ways forward:
- Have the guitar sound to the audience come from Cabinets, possibly with Kone's. Probably not optimal unless you play at very small venues or you want to build a wall of cabinets, á la Angus Young.
- Just use FRFR for your monitor as well.