This may be common knowledge, but I’ve noticed that if I don’t adjust global velocity to around 70 and utilize varying velocity levels- the mix of the 6 tracks has zero headroom and causes great ear fatigue, even with panning, like everything is compressed or limited to the max. It’s especially noticeable on synth parts, they sit much better in the mix with varying low velocity levels. Just thinking out loud in case somebody finds this informative…
