A configurable coprocessor interface between a central processing unit and a coprocessor is provided. The method includes extracting source text from a graphical representation of the source text in an associated audiovisual program; translating the extracted source text into a target text in a language different than a language of the source text; and presenting the target text in a human perceptible format in a synchronized manner with the associated audiovisual program. The audio processing unit is typically in communication with both the wireless interface and one or more wired physical interfaces. According to the invention, the gas-permeable chamber wall comprises a friction surface consisting of material which is resistant to wear, on the inner side facing the yarn enmeshment.