The shape of egg cartons might remind you of egg crate foam, and that structure exists primarily to diffuse sound, not to absorb it. Egg cartons won't suck up a significant amount of sound ...

Cymat’s Aluminum Foam, marketed under the trade name of ... Along with its unique appearance, it has sound-absorbing properties making it ideal for applications requiring both sound absorption ...

Cellular cast aluminum foam, sound absorbing properties, strong yet lightweight panels, versatile material, contains up to 100% recycled content, corrosion resistant. Alusion™ Small Cell ...