Zeolitic material for improving loudspeaker performance

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;
• a permeable partition to divide the back volume into a rear cavity defined between the speaker driver, the housing, and the permeable partition and an adsorption cavity defined between the housing and the permeable partition, and wherein the permeable partition includes a plurality of holes that place the rear cavity in fluid communication with the adsorption cavity to allow the gas to flow between the rear cavity and the adsorption cavity;
• and
• an adsorptive filler positioned in the adsorption cavity to adsorb the gas, the adsorptive filler comprising an assemblage of beads including a plurality of beads formed from a zeolite and a polymeric binder, wherein a non-zero percentage of beads in the plurality of beads has a shape including:
• a base shape having a continuous exterior formed of a first dome portion and a second dome portion, the first and second dome portions being joined together to form a spheroid with a polar axis, a polar dimension along the polar axis, and a transverse dimension normal to the polar axis, and
• an indentation formed in one of the first and second domed portions, the indentation having a depth extending toward a center of the base shape along and in the direction of the polar axis and a width in a direction normal to the polar axis, wherein the polar dimension is a polar diameter and the depth of the indentation is between 5% and 50% of the polar diameter, or wherein the transverse dimension is a transverse diameter and the width of the indentation is between 5% and 35% of the transverse diameter.

A method for manufacturing of an assemblage of particles, the method comprising:

• preparing an aqueous suspension by:
• dispersing a zeolite powder in water,
• adding a polymer binder to the suspension and mixing to form a zeolite-polymer suspension, and
• adding hydrogen peroxide (H2O2) to the zeolite-polymer suspension;
• producing droplets of the zeolite-polymer suspension by forcing the zeolite-polymer suspension through a nozzle;
• and
• freezing the droplets of the zeolite-polymer suspension emerging from the nozzle.