Abstract: Embodiments of the inventive subject matter described in this application are directed to headset audio systems that incorporate components designed to improve sound reproduction in certain ranges. For example, in some embodiments, an acoustic chamber and a venting portion are incorporated into an internal portion of a headset audio system such that the vent is configured to improve bass response. Different vent shapes and sizes can affect speaker performance. Moreover, in some embodiments, the acoustic chamber can additionally include a vent.

Abstract: An electron gun including a cathode, a beam forming region, an electron lens region, and a high voltage wire is provided. The beam forming region is disposed behind the cathode to make the electrons produced by the cathode become an electron beam. The beam forming region has a control electrode G1 and a screen electrode G2 sequentially. In addition, the electron lens region is adjacent to the beam forming region. The electron lens region has a focusing electrode G3, a focusing electrode G4, and a focusing electrode G5, wherein the focusing electrode G3 and the focusing electrode G4 overlap. Moreover, the high voltage wire is disposed in the electron lens region to connect the focusing electrode G3 and the focusing electrode G5. A cathode ray tube and a projector applying the electron gun are also provided.