worlds first MEMS speaker going mass production, page-2

The U-sound MEMS speaker is an analogue device, unlike the AudioPixels digital MEMS speaker. Although the U-sound MEMS can be used in an array of 40 or 80 chips, it still requires an accompanying woofer to produce the low frequencies. If you research both companies’ products you may conclude that AudioPixels has a very much superior concept.
Yes, an AKP investor needs patience, but the rewards will come.