A method for film production includes the steps of obtaining information on the position of a defect (D) in a separator (12a) and providing marks (LA, LB) at the respective positions in the vicinity of the defect (D), the marks indicating the position of the defect.

Protected microphone systems may include one or more dampeners, one or more cavities, or a combination thereof to minimize the vibration sensitivity of a microphone of the protected microphone systems. The dampeners, when present, may be constructed of a foam material or a thin metal material.

Protected microphone systems may include a protective layer and one or more cavities to minimize the vibration sensitivity of a microphone of the protected microphone systems. The protective layer may be constructed of a mesh material. The mesh material may be constructed of a polyester monofilament material.

Protected microphone systems may include one or more dampeners, one or more cavities, or a combination thereof to minimize the vibration sensitivity of a microphone of the protected microphone systems. The dampeners, when present, may be constructed of a foam material or a thin metal material.

Protected microphone systems may include one or more dampeners, one or more cavities, or a combination thereof to minimize the vibration sensitivity of a microphone of the protected microphone systems. The dampeners, when present, may be constructed of a foam material or a thin metal material.

To easily specify the position of a defect in a separator, a method for producing a separator original sheet (12b) includes the steps of: forming a separator original sheet (12b) including a separator original sheet (12c) and a heat-resistant layer coated on the separator original sheet (12c); detecting a defect (D) in the separator original sheet (12b); and recording information including information on a position of the defect (D) which position is a position in the width direction of the separator original sheet (12b).

Protected microphone systems may include one or more dampeners, one or more cavities, or a combination thereof to minimize the vibration sensitivity of a microphone of the protected microphone systems. The dampeners, when present, may be constructed of a foam material or a thin metal material.

A method of film production includes the steps of obtaining defect information including information on the position of a defect (D) in a separator original sheet (12b), slitting the separator original sheet (12b) to produce a plurality of separators (12a), and determining, on the basis of the defect information on a single defect (D), that a separator (12a) actually having the defect (D) and another separator (12a) adjacent to the above separator (12a) are defective.

Protected microphone systems may include one or more dampeners, one or more protective layers, or a combination thereof to minimize the vibration sensitivity of a microphone of the protected microphone systems. The dampeners, when present, may be constructed of a foam material or a thin metal material. The protective layer may be a membrane, a mesh, or any suitable material. The protective layer may be air permeable or non-air permeable.

A method for film production includes the steps of obtaining information on the position of a defect (D) in a separator (12a) and providing marks (LA, LB) at the respective positions in the vicinity of the defect (D), the marks indicating the position of the defect.