Sony MDR-NC500D Manual

Noise canceling effect

Anti dependency of noise
canceling effect against
individual difference / fitting
difference

Miniaturization

The Internal Block Diagram of MDR-NC500D is shown below:

The noise detection microphone of MDR-NC500D collects noise

around the ear.

The noise signal is digitized through the microphone amplifier and

high-speed A/D converter and is inputted in Digital Signal Processor
(DSP). Then the DNC software engine inside DSP generates the canceling
signal, which is inverted to the original noise.

Meanwhile, the regenerative signal of a music source supplied from

the audio input terminal is digitized by the high-speed A/D converter and is
inputted in DSP. Then, its frequency characteristic is adjusted by the digital
equalizer inside DSP. After the canceling signal is added, the regenerative
signal is reproduced as a sound by way of the high-speed D/A converter,
the headphone amplifier and the driver unit.

Mixing of the reproduced sound and the outside noise at the ear

negates only environmental noise, making it possible to enjoy music etc.
calmly.

Feedback type

Excellent

Better

Less suitable

Feedforward type

Good

Average

More suitable

Internal Block Diagram of Noise Canceling
Headphones of MDR-NC500D

Audio In

A/D

converter

System

controller

Digital

equalizer

DNC software

engine

D/A

converter

A/D

converter

Detection

microphone

Headphone

amplifier

Driver unit

Microphone

amplifier

High-speed A/D,
D/A converter