Quiet confidence usually comes from prep nobody saw. Loud confidence sometimes comes from hoping nobody checks.

The two look similar from outside and are built from opposite materials. One is the residue of work, where you already know what you can do, so there is nothing to announce. The other is a performance aimed at preventing inspection, and the volume is doing the job the preparation was supposed to do.

Watch which kind you are running on before your next tryout or presentation. If you are talking yourself up more than usual, that is often a sign you know you are short. Spend the energy on the preparation instead and let the quiet version take care of itself.