(Ca0.1Ba0.9)TiO3 + x wt % MnCO3 [x=0, 0.2, 0.5, 1.0] (CBT-Mx) ceramics were prepared by conventional sintering, and their dielectric and piezoelectric properties were measured. The mechanical quality factor (Qm) of CBT was markedly enhanced by Mn addition and reached 2400 when x=0.5. The dielectric loss tangent (tan δ) was 0.0023 at room temperature. The Curie temperature (TC) was 133 °C. Then, the high power characteristics of CBT-M0.5 were investigated. The maximum vibration velocity (v0) of CBT-M0.5 was 1.1 m/s and was higher than that of Pb(Zr,Ti)O3-based ceramics (Hard-PZT). The heat generation of CBT-M0.5 was smaller than that of Hard-PZT at the same v0. The resonant frequency (fr) of CBT-M0.5 was stable up to v0 of 1.1 m/s. Additionally, the temperature stability of fr was investigated in the practical application temperature range (from -20 to 80 °C). The amount of change in fr for CBT-M0.5 was larger than that for Hard-PZT below 10 °C.