Cavities and active regions

A mobile electronic device, comprising:

• a case body;
• and
• at least one speaker unit or microphone unit in the case body;
• wherein
• each speaker unit or microphone unit comprises a housing that defines at least one cavity region, a vibratable element in or proximate to the cavity region and an active region that comprises a particulate adsorbent material comprising i) microporous organic polymer (MOP) material, and/or ii) metal organic framework (MOF) material treated with a hydrophobic coating or a membrane.

A speaker system, comprising:

• a speaker unit;
• and
• a cabinet forming a chamber at a back region or side region of the speaker unit largely filled with a felt comprising of a gas permeable upper layer, ultra-fine particles of gas adsorbing material dispersed at high concentrations within a fibrous matrix without using binder, and a permeable or impermeable back layer;
• wherein
• the gas-adsorbing material may be a Metal Organic Framework material treated with a hydrophobic coating, or an amorphous microporous organic polymer (MOP), featuring component materials with innate hydrophobicity, such as Poly-dichloroxylene (P-DCX).

A microphone system, comprising:

• at least one transducer element for converting sound to an electrical signal;
• optionally a preamplifier that receives an output from the transducer element;
• a housing or cabinet at a back region or side region of the transducer element;
• and an active region that comprises at least one support element and adsorbent material comprising a particulate adsorbent material comprising i) microporous organic polymer (MOP) material, and/or ii) metal organic framework (MOF) material treated with a hydrophobic coating or a membrane.