It would be a huge mistake to assume that all the design work happened elsewhere and that Apple had no substantial input. A reference design is far from having a finished product, even electronically. The ultimate circuit design was still Apple's, as far as any outsider can tell.

"The value is putting it all together and optimizing the design to eek out the best performance, get the best power utilization, the best audio performance," says Wolfson's Hayes. "That is not a trivial task by any means. Sometimes it's very difficult in a cost constrained [situation] and small form factor to get the performance." Factors that can influence the final sound can be the circuit board layout, the circuit design itself, the handling of the power supply and the overall implementation.

"It's a combination of all those things that create that high-quality performance," Hayes adds.

In his opinion, and in that of many reviewers, Apple hit a home run. "Certainly I think it's about the best audio quality we've come across for that type of product in the marketplace in terms of intrinsic audio quality and delivered audio quality," Hayes says.