Arrangement Support That Stays Supporting
The final constraint is about where the vocal sits in the mix, but not in the technical sense. Make one decision: this is either a vocal-forward arrangement or a production-forward arrangement. Pick one and commit.
If the vocal is the focus, every other element in the arrangement has to clear out when the voice enters. That means the guitar part drops the busy riff and plays fewer notes. The synth pad narrows its frequency range. The drums pull back on the overheads. You're not mixing around the vocal. You're building the arrangement in service of it.
If the production is the focus, the vocal becomes another instrument. It doesn't have to cut through every moment. It can duck behind a synth line for a bar, then re-emerge. It can stay low in the mix for an entire verse, creating tension that releases when the vocal finally comes forward in the chorus.
Both approaches work. What doesn't work is the middle ground, where the arrangement fights the vocal for space and nobody wins. The constraint of choosing eliminates that fight entirely.
When you're done tracking and editing under these constraints, listen back to the final vocal. It won't sound like it was limited. It will sound like every decision was the right one, because you forced yourself to make real decisions instead of deferring them. That's the entire point. Constraints don't reduce creativity. They reveal it.