Noise-reduction technology built into Apple's A5 processor

Like I've said before, if you want Siri, you gotta pay for her.

It has been revealed that the A5 processor in Apple's iPhone 4S contains licensed noise-reduction technology from a start-up company called Audience, and that this is the likely reason why the Siri voice-assistance won't be back-ported to earlier versions of the iPhone.

The details of the Audience/Apple partnership was revealed in paperwork filed for an initial public offering of stock.

We sell our products to Foxconn International Holdings, Ltd. and its affiliates (collectively, Foxconn) and Protek (Shanghai) Limited and its affiliates (collectively, Protek), each a major CM that produces mobile phones containing our processors almost exclusively for Apple. In 2010 and the nine months ended September 30, 2011, Foxconn and Protek collectively accounted for 82% and 79% of our total revenue, respectively. We entered into an agreement with Apple in 2008, which governs our relationship and under which we sell custom processors to Foxconn and Protek and license our processor IP to this OEM for other mobile phones.

An iFixit teardown of the iPhone 4 had uncovered dedicated Audience silicon, but with the introduction of the iPhone 4S the "earSmart" technology was directly integrated into the A5 processor. earSmart is a smart digital signal processor used to remove background noise and even other voices so calls sound better in noisy environments.

Commencing in the three months ended December 31, 2011, Apple has integrated our processor IP in certain of its mobile phones.

Apple has also been granted a license for next-generation technology:

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 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. We have granted a similar license to this OEM for a new generation of processor IP; however, this OEM is not obligated to incorporate our processor IP into any of its current or future mobile devices.

This revelation explains a number of things:

  • Why there as no separate Audience chip in the iPhone 4S
  • Why the A5 processor was so large
  • Why Apple didn't backport Siri to earlier handsets (although people have been able to get Siri to run on the iPhone 4, it's likely that quality would suffer thanks to the earlier-generation of noise-reductions)

Like I've said before, if you want Siri, you gotta pay for her.

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