Master EQ in rekordbox on Mac (windows soon) without losing headphone cue

 I ran into this exact problem and ended up building the workaround, so I'll share what I learned in case it helps.

The usual advice is Audio Hijack or a manual aggregate device. Both work for the master, but they break headphone cue on a DDJ, once rekordbox is pointed at the aggregate, you lose the cue path on the controller. That was a dealbreaker for me.

 What actually works: build an aggregate that contains BlackHole first and the controller second. rekordbox then sends Master to BlackHole (channels 1/2) and Headphones to the controller's PHONES pair. A separate app reads BlackHole, applies the EQ, and writes back to the controller's MASTER pair. The cue path never goes through the correction, so it stays dry and adds zero latency.

 I built a small Mac app that sets all of this up automatically because doing it by hand every time was painful. Not selling anything, I'm just trying to find out whether other people actually want this or whether I solved a problem only I have.

Two questions if anyone's played on less-than-great speakers:
 What speaker do you usually play on, and is it bad enough that you'd bother correcting it?