Aside, it would be interesting to know what kind of audio monitoring ATK uses in editing. The quality is solid, though the overall level is often on the weak side. But there's a low-end rumble that I can't believe is getting missed during recording or the mix. At first I thought it was ground hum, but it undulates, so maybe it's HVAC bleed? It's subliminally off-putting, whatever it is. I hope it can be tracked down!