Superconducting transition-edge sensors (TESs) are the state-of-the art technology for microcalorimeter and bolometer applications across the electromagnetic spectrum. We propose to design, fabricate, and test what we call a magnetically-tuned TES (or MTES). The leading theoretical TES physics understanding predicts our MTES concept will take the current state of the art TES and (1) Increase the signal, (2) Decrease the pulse recovery time, (3) Reduce the noise, and (4) Increase the energy resolving power. The magnetically-tuned TES (or MTES) takes characteristics that we have only recently come to understand are present and important in all state-of-the-art TES sensors and uses them in an interesting new combination. Magnetic tuning simply changes the resistive transition of the TES sensor.