| CPC H04R 1/22 (2013.01) [G10K 11/18 (2013.01)] | 26 Claims |

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1. A portable electronic device comprising:
an enclosure having an enclosure wall that defines a first chamber, a second chamber, an acoustic opening from the first chamber, and an acoustic vent from the first chamber or the second chamber; and
an electroosmotic flow valve having a driven member and an electroosmotic pump, wherein the electroosmotic pump is operable to move the driven member in a direction parallel to a direction of fluid flow through the acoustic vent between a position adjacent a substrate layer of the electroosmotic pump and a position covering the acoustic vent to open and close the acoustic vent.
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