https://newatlas.com/electronics/silicon-micro-loudspeaker-fraunhofer-arioso/?utm_source=New+Atlas+Subscribers&utm_campaign=512f88fc5c-EMAIL_CAMPAIGN_2020_04_03_08_14&utm_medium=email&utm_term=0_65b67362bd-512f88fc5c-91020877
this is kinda interesting.