The design method for a cabinetless transparent speaker is developed in this research. The speaker is composed of a vibrating membrane, and its driving electrodes. All of them are transparent. The membrane is made from electret, and the electrodes are perforated plastic plates coated with transparent conducting layer. The thickness of the whole integrated structured is no more than one millimeter. Several issues are studied. First of all, the driving mechanism of the electret is investigated by electrostatics. At the same time, it is found that the speaker with single electrode generates distortion, while the speaker with double electrodes doesn't. Secondly, the acoustic impedance of a perforated plate of is examined. It is with the positive dependence on the thickness of the plate, as well as the negative dependence with the diameter of each hole and the porosity. Thirdly, a fluid-structure coupled finite element model is built to analyze the acoustics with various magnitude of pre-stress and charged density of the membrane. Finally, the sound pressure level (SPL) is generated and is used to evaluate the performance of the speaker.