Comment by robmiller

We use honeycomb panels in acoustics construction as means for high stiffness (low deflection) with the tradeoff of low mass. Often we laminated a thin layer of plywood to each side to improve the stress skin system. Orchestra shell towers are a common example of this, though we are also doing this for portable seating towers that need to reflect sound too. There are both wood pulp and aluminum versions commonly available in the US.