Acoustic drums must be mic'd. You cannot play the jammr session on an amp in the room - it will be picked up by the mic, causing a loop, which will sound like a very long delay.
So drummers *must* use headphones to listen to the jam.
What the drummers need, then, is the capability to do two mixes:
- One that includes the drums, other players & the metronome, for their headphones
- One mix of drums-only, to send to Jammr so others can hear the drums
How best to do this depends on your audio card/mixer configuration.
- If your audio device has a direct monitoring feature, you can use that to hear yourself, and disable “Play back my audio” in jammr. You don't need to “play back my audio”, because you can hear yourself thru the monitoring feature.
- If your audio device does NOT have a direct monitoring feature, you should enable “Play back my audio” and send the jammr signal (which now includes you, the others, and the metronome) to the headphones.
The original post by stefenha here includes all of these points:https://forum.jammr.net/topic/1987/
This all assumes a basic config issue - I think such issues usually are. If you really are experiencing true audio latency of a few ms more than you find acceptable, you need to find a way to tune your audio device & system. Lots of sources on the web to help you do that.
Hope this helps…