Why iPhone 4 Users Won’t Officially Get Siri

Right after the iPhone 4S, and with it Siri, launched, a number of people wondered why won't Apple let iPhone 4 users get Siri.

Some reasoned that the huge number of iPhone 4 devices in the market, along with iPhone 4S users would overload Apple's servers in North Carolina, while others said that since the software was in beta, Apple wanted to restrict the number of users.

Linley Group chip analyst, Linley Gwennap, proposes another theory, one that seems the most credible until now. He says that Apple's dual core A5 chip includes noise reduction technology called "earSmart" licensed from a Silicon Valley start-up, Audience.

Although tear downs of the iPhone 4 also included a dedicated Audience chip, the technology built into the outdated chip was effective only when the microphone was placed next to the speaker's mouth.

In his report, Gwennap writes:

"Even after accounting for the dual Cortex-A9 CPUs and the large GPU that provides the A5 with industry-leading 3D graphics performance, the remaining die area seems too large for the usual mundane housekeeping logic. To reduce system cost and eliminate the extra package required for the Audience chip, Apple cut a deal to integrate the noise-reduction technology directly into its A5 processor, which appears in the iPhone 4S.

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 Gwennap's reasoning sufficiently explains the absence of Siri from the iPhone 4, it doesn't explain why the iPad 2, which also has an A5 chip, doesn't run Siri. Our assumption is that Apple wanted Siri's AI engine to mature a bit more, before bringing it to more devices.

CNET notes that Audience had disclosed its relationship with Apple in its S-1 filing, when it decided to go public:

Commencing in the three months ended December 31, 2011, Apple has integrated our processor IP in certain of its mobile phones. Pursuant to our agreement, this OEM [original equipment manufacturer] will pay us a royalty, on a quarterly basis, for the use of our processor IP for all mobile phones in which it is used.

Audience's technology resides not just in Apple's in-house chips, but also in devices manufactured by Samsung, LG, HTC and others.

This, however, doesn't mean that Siri running on an iPhone is impossible. In fact, we've seen several Siri ports by hackers which make Apple's virtual assistant run on various iOS devices. It just means that the performance of Siri running on an iPhone 4 won't be what Apple deems sufficient.

[source CNET]