I'm missing something here, hopefully someone can help. This just started. Here's the scenario: Kontakt 5 open with 2 instruments (drumkit to Ch 1, Bass to ch 2). 2 midi tracks in X1, one set for ch 1, the other for ch 2. Input is my M Audio Radium49 for both. Output, of course is Kontakt. I record a simple drum track on 1. Then go to record bass on 2, but I can hear the drums every time I hit a key. I have the bass track selected, but I can still hear both when I play. I just finished a symphony project, and the track I had selected on X1 was what Kontakt played. But now I'm hearing both and it's driving me crazy. Is there something obvious I'm missing? Thanks!

check input echo

Still doing it. It's as if they are both on the same midi channel - which they are not. The lower notes of the keys trigger the bass, and the high notes start triggering drums. This is whether I have track 1 (drums) selected or track 2 (bass) selected.

Ok - I inserted a new Kontakt instance, and added a bass instrument to it's ch 1 (so - now it's Kontakt 2, midi channel 1). I create a new midi track in X1, set it for Kontakt 2, channel 1, start playing and I can still hear the drums from Kontakt 1, ch 1. Now I'm lost, and I hope I have not lost you! Hopefully I've explained it well enough.

You need to be on separate MIDI channels as well as audio tracks

The default is OMNI which is listening on all MIDI channels.

I have input of each midi track set to my Radium (I have tried omni, 1 and 2) and my output is set to Kontakt and my channels are set to 1 and 2 respectively. And in Kontakt I have drums to Ch 1, and bass to Ch 2. I'm not sure what else I can change??? Help!!

Have you set the midi track inputs individually to channel 1 & 2?
Is the Radium only outputting on a single channel for each instrument?

Inside Kontakt where it says Midi Ch (A)1. Click the pulldown menu and set it to omni for all midi channel inputs or individually set where they will recieve midi from ch1 (host), ch2 (host). Now your seperate midi channels should be recieved as you are sending them Drums ch1. Bass Ch2.

I think I see the problem. The Kontakt drum kit I'm using on Ch 1 says "ch1 plus group". I have no idea what "plus group" means, but I can't seem to make that go away. No matter what channel I select, Kontakt adds the "plus group" to it. I'm not in front of my computer right now, but in a bit I'll simply try a different kit and see if the problem goes away. I do like this particular kit for this song, so can anyone tell me how to remove the "plus group" part?

In Preferences, I set Sonar to echo currently selected track, and then I turn echo off on MIDI tracks.  Otherwise, this will drive you nuts.