Mycelium-based composites have the potential to replace petrochemical-based materials within architectural systems and can propose biodegradable alternatives to synthetic sound absorbing materials. Sound absorbing materials help improve acoustic comfort, which in turn benefit our health and productivity. Mycelium-based composites are novel materials that result when mycelium, the vegetative root of fungi, is grown on agricultural plant-based residues. This research presents a material study that explores how substrate variants and fabrication methods affect the sound absorption properties of mycelium-based composites grown on paper-based waste substrate materials. Samples were grown using Pleurotus ostreatus fungi species on waste cardboard, paper, and newsprint substrates of varying processing techniques. Measurements of the normal-incidence sound absorption coefficient were presented and analyzed. This paper outlines two consecutive acoustic tests: the first round of experimentation gathered broad comparative data, useful for selecting materials for sound absorption purposes. The second acoustic test built on the results of the first, collecting more specific performance data and assessing material variability. The results of this study display that cardboard-based mycelium materials perform well acoustically and structurally and could successfully be used in acoustic panels.

Mycelium-based composites, heralded for their functional versatility in architecture, have emerged as a pivotal subject in sustainable biomaterials research in recent years. Within this context, conventional fabrication techniques for mycelium-based composites, predominantly relying on molding, are increasingly deemed inadequate, and a shift towards more sustainable and flexible fabrication processes is necessary. Within the larger body of work studying additive manufacturing of mycelium-based composites, our study presents a robotic additive manufacturing approach employing hybrid slicing and conformal 3D printing to fabricate geometrically complex architectural panels. The panels, however, geometrically deform as fungi colonize the 3D printed substrates post-fabrication. Addressing this, we have integrated a computer-vision-based post-fabrication analysis, adept at meticulously documenting and quantifying geometric deformations occurring during the material cultivation stage. By harnessing the precision of conformal 3D printing together with this comprehensive post-fabrication analysis, our research presents a novel framework for accurate materialization and geometric analysis of mycelium-based composites, signposting the direction for future architectural endeavors.