Wonder why Apple keeps saying Siri will not be available on iPhone 4? Read below for the real explanation.
Apple’s A5 chip incorporates dedicated noise reduction circuitry by Audience, Inc., which optimizes the performance of Siri voice recognition on iPhone 4S.
Although earlier generation of this circuitry was already available on iPhone 4, it was not optimized for voice recognition technology.
“by imitating the complex processing that occurs from the inner ear to the brain, Audience’s intelligent earSmart technology distinguishes and interprets sounds as people do naturally. In a mobile device, the earSmart processor effectively isolates and enhances the primary voice signal and suppresses surrounding noise–for both transmit and receive–to enable clear conversations nearly anywhere.”
They also note that “far-field uses are more vulnerable to background noise interference and poor voice quality given the speaker’s distance from the device,” which means speaking to a TV e.g. Apple TV across the room would be far more difficult to correctly recognize speeches compared to Siri on iPhone 4S due to the distance between the source and the destination.
It’s quite common for Apple to “white label” components on their logic boards. That means you won’t be able to see the brand or manufacturer on the components. In this case, Chipworks, a company that does reverse engineering and patent infringement analysis to the world’s largest semiconductor and microelectronics companies, decamped the part and found Audience’s name printed on the chips die marking.
Chipworks thought that “the iPhone’s audio cancellation capabilities are very impressive, outperforming every non-Audience powered cell phone we’ve tried.”
Finally, a report on CNET mentioned “this situation helps explain why Apple does not offer Siri as a software upgrade on the iPhone 4. Although the older phone includes an Audience chip, the company has since improved its technology to handle ‘far-field speech,’ which means holding the device at arm’s length rather than directly in front of the mouth”
Although it’s possible to hack older iPhones to enable Siri, there’s still an underlying hardware limitation to allow Siri to achieve its potential performance.