New to Pioneer controllers & rekordbox.

Before diving into anything else, I'll give you the heads-up that other users have posted about issues when combining rekordbox with a Focusrite in the same system. This is purely anecdotal from their comments and experiences, and you may not have the same issues... but if you're trying to output the audio from rekordbox via the Scarlett, I can't provide any support for those problems.

One thing you didn't mention is what the actual levels are at. Have you adjusted the TRIM knob on each channel to a position that, when the channel fader is all the way up and the master knob is around 2 o'clock, the meters are showing peaks around the first orange LED?

I had to crank all levels, trim, headphone (which sounded out of sync when cued on the playing track), master in the software and master on the controller and the sound was still very low but the controller was peaking like that, scarlett was pretty high volume as well....usually when i interact with audio cards i have to set up some sort of external audio routing through inputs but when i have done that in the past i tend to lose cue channels unless i can output each channel into it's own mixer channel externally then i can use the mixers cues, in the case of having a controller i want to avoid all this audio frankensteining.

That's a shame about the focusrite issues, are there plans to make it more compatible? I like pioneer gear, your guys CDJ game is crazy good. This issue topic didn't come up at point of sale. i returned a Traktor Kontrol S2 MK3 for this cause i felt it would be less disappointing....as long as i can control software and get loud audio i'll be happy as it's not a pro level controller. i can live not using the focusrite inside the software but it is the primary card with my yamahas...if i HAVE to plug directly into the speakers i can do RCA>TRS cause the card is hooked up to XLR>TRS and has 2 ports which would avoid me switching cords anytime i wanna play.

I was trying to go around the focusrite withy my Numark X6 but it's master plugs into the focusrite, so i don't need it to drive the software but the all volumes maxed plugging into the numarks LINE maybe reached some yellow, thing is with the numark at 0 volume & fader down still bypassed it and sound came out(i feel like maybe it was going through USB). I just need it to work plugged into LINE and the headphone cues to work cause i can't use numarks mixer cue if there's only 1 LINE plugged in. Can the controllers headphone cues work in external mode?  is this enough information?

If I understand correctly, you're wanting/trying to get the master audio to go from the Focusrite, but you want the headphone cueing through the DDJ-400?

Have you considered selecting the DDJ-400 as the main audio device in rekordbox, then using the PC Master Output? That would send the normal signal to the DDJ and a copy of the master audio output to the default audio device for the OS. If you have that selected as the Focusrite, it may just work to send the signal there as well. If the levels are still an issue, you may be able to adjust them (depending on your OS and the configuration of the devices).