If you put a piece of filter paper in front of a speaker, you can actually boost the "wind" from the sound waves by over 2,000%.
April 10, 2026
Original Paper
Order-of-magnitude enhancement of airborne acoustic streaming using porous materials
SSRN · 6546325
The Takeaway
Sound waves can actually push air, but the force is usually too weak to be useful for anything beyond tiny vibrations. By adding a simple layer of porous fabric, researchers found they could supercharge this physical force, paving the way for buttons you can "feel" in mid-air or better acoustic levitation.
From the abstract
Thin layers of porous materials are shown to produce an unexpected order-of-magnitude amplification of bulk-driven acoustic streaming generated by a high-powered airborne transducer, increasing the streaming velocity from 0.12 m/s to 2.5 m/s. Particle image velocimetry (PIV) measurements were used to characterise the streaming field produced by a Langevin horn operating at 27 kHz with a range of thin porous layers (various filter papersand a woven Kevlar fabric) placed in front of the source. We