Coating for improving loudspeaker sound quality

A process comprising:

• preparing a slurry including a binder and a zeolite;
• spraying the slurry through a nozzle having a nozzle diameter;
• and
• depositing a porous acoustically active coating on a substrate by directing the sprayed slurry through an environment onto the substrate, the substrate being positioned at a distance from the nozzle, and the coating including convex particles connected by concave connectors.

An electronic device comprising:

• an audio speaker comprising:
• a housing defining a back volume behind a speaker driver, wherein the speaker driver can convert an electrical audio signal into a sound so that the sound can propagate through a gas in the back volume, and
• a porous acoustically active coating deposited on at least one interior surface of the back volume, the porous acoustically active coating including convex particles connected by concave connectors, the convex particles and concave connectors being made of a binder and an adsorptive substance;
• and
• a processor coupled to the audio speaker and to a memory, the memory having stored therein one or more application programs which include instructions that, when executed by the processor, transmit the electrical audio signals to the audio speaker for transduction into sound.