1. How to use X1 MK3 and Apollo sound card to monitor?
Thanks! !
2. Some buttons on X1 MK3 will malfunction.
so I also need a headphone amplifier to link to the mastering monitor of my sound card?
Internal is correct.
But unless you got more then just the two options it looks like your interface only has 2 channel. Which I asked you right from the beginning.
Best is a single interface with 4 channels (two stereo outs)
On mac you can combine multiple interfaces into one. In that case you could use the 3.5mm out on your laptop + the apollo. But I don't know how well that works.
If you are fine with mono you can use the DJ cable https://www.native-instruments.com/en/products/traktor/traktor-for-ios/traktor-dj-cable/
