Ann: Quarterly Activities/Appendix 4C Cash Flow Report, page-407

This idea seems to be completely at odds with the design of the AP micro-pixel array DSR MEMS.

1. The point of the AP micro-pixel array DSR MEMS is to reconstruct a coherent wavefront out of the combination of individual air pulses such that a faithful replica of the original sound wavefront is generated from the front of the MEMS plane and propagates as a planar wave moving out perpendicular to it. i.e. the sound is directional and is the composite of all the individual pulses that are themselves carefully distributed in space across the MEMS, and actuated in particular sequence order to enhance and preserve the coherence of that front. I think this is right at the heart of the DSR technique. I think that it was one of the big concerns with the development of the waterproofing cover (below) which was developed to accommodate the MEMS surface being able to be unimpeded by obstacles while protecting the MEMS from dust and vapour.
2. Blocking the wavefront as soon as it is generated by putting something physical in its way, in this case a second MEMS chip, would seem like a complicating factor that works against that function. In particular it would probably completely eliminate the ability to produce directional "beams" of sound. I cannot see that this idea is compatible with an AP MEMS.
3. The comment that "usually the chips are stacked on the substrate" definitely does not reflect the positioning of every available design image of the AP MEMS assemblies. Apart from the fact that in AP's case "usually" has no prior examples to cite as comparisons, this description does not sound anything like a micro-pixel array DSR MEMS. It seems far more like USound's MEMS in which a vibrating membrane produces analog sound directly and in some designs appears to be reflected around inside its housing before exiting from an orifice or even a slit on one edge. This idea would suit such a construction.

"... Audio Pixels Granted Several Patents
SYDNEY, Australia, [15 August 2013] – Audio Pixels Holdings Limited (AKP:ASX; OTCQX:ADPXY), a fabless semiconductor company focused on the development and production of MEMS based digital speaker chips revealed today that since the beginning of the new year its intellectual property portfolio has expanded to include 5 new patent families. The patents granted in various patent jurisdictions around the world include 2 patent grants for the Basic architecture and functional principles of its MEMS based digital speaker; control of volume and tone in digital speakers; Directivity patterns in direct digital speakers; and in the field of Packaging of MEMS based digital speakers

"We are excited to see our patents granted as they acknowledge Audio Pixels as a true pioneer and innovator in digital speaker technologies," said Yuval Cohen, Co-Founder and CTO. Audio Pixels patent portfolio now encompasses not only the principle architecture and functionality of digital speakers, but also critical innovations that enable the technology to be commercially exploited.

He added, “For example, the recent patent granted to us for Dust Protection covers a very unique innovation in MEMS packaging that provides the highest levels of protection for the chip from the environment while still permitting the sound waves generated inside the chip, to radiate to the environment with near negligible attenuation”. MEMS packaging is considered by the industry at large to be far more challenging than the packaging of traditional IC’s due to the diversity of requirements associated with providing the ability for the transducer (or sensor) to be in touch with the environment, yet protected from it. ..."

In short I do not think this patent application is relevant to AP chips. But it does indicate that EM is well aware of all other emerging speaker designs, and is very serious about establishing its own presence in the industrial audio market.