Hi @donmoyer, thanks for reaching out.

Lots of my favorite producers leave that window open for vocals. There's one mastering engineering that told me once the same thing (he didn't use the term "tessitura", though). He was giving advice to producers and he commented on how important it is not to have frequencies "competing" with each other. I totally agree with that.

Mixing and production is a huge topic, and this article was rather oriented around sound exploration and creative uses of the transposition algorithm.

Thanks for your insight.

Take care,

Miguel