When a ribbon tweeter is driving by a current signal, the heat will build up on the ribbon diaphragm. Inside the ribbon tweeter, it is more like in an adiabatic condition than in an isothermal condition. Under a short term high power music signal driving, the surface temperature of the ribbon diaphragm might rise up to more than 100 degree C or even more than 200 degree C. Therefore the mechanical behavior of substrate material of ribbon diaphragm at elevated temperature plays an important role to the sound quality and the high power performance of a ribbon tweeter. The dynamic mechanical analysis of substrate materials for ribbon diaphragm is shown below for comparison. Kapton-base substrate material has the highest ranking for used as the substrate material for ribbon diaphragm. In addition, dynamic behavior of the Kapton material can be finely tailored by selecting raw materials of different molecular structure during the synthesis.