Sony showcased its new MDR-NC500D digital noise canceling headphones in January 2008 at the 2008 International CES. Held in Las Vegas, International CES is a trade show for consumer electronic products. Sony announced that these new headphones, the world's first (*) digital noise canceling headphones, would go on sale in Japan in late April 2008.
Conventional noise canceling systems have relied on analog signal processing. Sony has brought together acoustic analysis technology, digital signal processing technology and transducer technology to create a digital noise canceling system.
* Based on Sony research in March 2008
* Conventional analog filters do not provide the necessary performance enhancement because of an inability to provide rapid isolation characteristics. With analog filters, any attempt to achieve stability (anti-oscillation performance) results in the exclusion of effective frequency bands that normally contribute to cancellation.