- From the Be a Treble Maker Studio - This bright motivational printable 18x24 TREBLE MAKER poster is a whole vibe. A purple cartoon skull with soft eighth-note accent feels edgy enough for high school and higher ed classrooms or studios.Teachers encourage vocal students to sing with confidence, and to make mistakes loudly, during rehearsals. Otherwise, how would they be heard, to then be corrected? "BE A TREBLE MAKER" reminds students to enjoy the process, and to sing loud, and proud!