Sony MDR-NC300D ユーザーマニュアル

Noise Canceling Headphones

MDR-NC300D

Product Information

产品信息

產品資訊

4-145-681-

11

(1)

2

Contents

1. Introduction ............................................................................................................................................................................................................................... 3

2. Outstanding Noise Canceling Performance ..........................................................................................................................................................................

4

2-1 Principles of Noise Canceling Mechanism ....................................................................................................................................................................

4

2-2 DNC Software Engine ...................................................................................................................................................................................................... 6

2-3 Automatic AI Noise Canceling Function ....................................................................................................................................................................... 8

2-4 Noise Canceling Optimization ...................................................................................................................................................................................... 10

3. High Quality Sound Technology ..........................................................................................................................................................................................

12

3-1 High Quality Sound by Digital Sound Enhancer .......................................................................................................................................................

12

3-2 S-Master Full Digital Amplifier..................................................................................................................................................................................... 16

3-3 Large 16 mm Dynamic Driver Unit ............................................................................................................................................................................. 17

4. Wearing Comfort ....................................................................................................................................................................................................................

18

4-1 Vertical In-The-Ear Headphones ..................................................................................................................................................................................

18

4-2 Hybrid Earbuds in 7 Sizes ............................................................................................................................................................................................. 19

Appendix: Total Noise Suppression Ratio .................................................................................................................................................................................

20

3

1. Introduction

Quiet surroundings are as important to the quality of sound reproduction as choosing the right audio equipment.

But in today’s world, your actual listening environment, especially when using a portable music device, is likely to be far from ideal

with exposure to all kinds of noise.

Since 1995, Sony has pursued the ideal listening environment through the development of noise canceling headphones and we

have succeeded in creating the ultimate noise canceling ear receivers using digital signal processing.

This pamphlet describes the features of the MDR-NC300D headphones in terms of the technologies – Sony’s acoustic technology,

signal processing technology and circuit technology – that have been built into the design of the headphones.

Features of the MDR-NC300D digital noise canceling headphones



Outstanding digital noise canceling performance



High-quality sound design



Excellent wearing comfort

4

2. Outstanding Noise Canceling Performance

2-1 Principles of Noise Canceling Mechanism

The MDR-NC300D headphones are equipped with a feed-forward noise canceling (NC) mechanism which cancels noise near the

eardrum by estimating what kind of noise it will be when it reaches the eardrum based on the ambient noise collected by the noise

detection microphone, and generating an inverted sound waveform.

As shown in the figure, the noise canceling performance greatly depends on the efficiency and precision of the NC circuit to

generate the noise canceling waveform.

The NC circuit uses the newly developed integrated DNC processor <CXD9952GR>. Compared with the previous analog type, it

boasts excellent noise canceling performance and outstanding sound quality.

5

Newly developed integrated

DNC processor

Leaked noise near eardrum

Added in space near eardrum

(noise canceling)

Inverted-phase noise canceling

waveform generated by NC circuit

Noise

Detection microphone

Driver

unit

NC

circuit

6

2-2 DNC Software Engine

Sony’s unique digital noise canceling technology and high quality audio processing technology come together in the Integrated

DNC processor to maximize the merits of digital processing, as shown in the figure.

The noise picked up by the noise detection microphone is digitalized by the A/D converter, and the optimal canceling signal is

generated through high-speed, high-precision digital filter processing by the DNC Software Engine at the heart of the processor.

After audio enhancement processing by the Digital Sound Enhancer (see page 12) via the A/D converter, the music signal from the

media player is added to the noise canceling signal in the DNC Software Engine.

The added signal is faithfully reproduced by the S-Master Full Digital Amplifier (see page 16), enabling high noise canceling

efficiency and dynamic music reproduction.

7

[Merits of digitalization]



In principle, computation is not affected by external electrical noise

NC

circuit

Analog Digital

NC

circuit



High precision and no variation

Analog Digital



Complex shapes not possible with analog filters are possible with

digital filters

Analog Digital

Frequency

Response

Frequency

Walkman and other AV devices

DSP

CXD9952GR

Driver unit

Noise detection

microphone

A/D converter

DNC Software Engine

AI Noise

Analyzer

Digital Sound

Enhancer

A/D converter

S-Master

Digital Amplifier

8

2-3 Automatic AI Noise Canceling Function

The characteristics of ambient noise vary depending on the situation. For example, the characteristics of ambient noise on a plane,

on a bus or a train, or in an office environment are different.

The AI Noise Analyzer inside the processor constantly monitors and analyzes the ambient noise. This function selects in real time

the most appropriate of the noise canceling modes provided by the headphones (Mode A: low to midrange frequency NC, Mode B:

ultra-low frequency NC, Mode C: wideband NC). In other words, it selects the mode that minimizes noise at the eardrum.

This advanced software function enables users to enjoy the optimum noise canceling effect automatically in any noise

environment.

Tips

Typically, “Mode A: low to midrange frequency NC” effectively reduces the noise present mainly on a plane; “Mode B:

ultra-low frequency NC” effectively reduces the noise present mainly on a bus or train; and “Mode C: wideband NC”

effectively reduces the noise present mainly in an office environment (OA equipment, air conditioning, etc.).

The AI Noise Analyzer analyzes the actual ambient noise in the user’s environment and selects the most effective noise

canceling mode.

9

DNC Software Engine

Noise

Noise detection microphone

AI Noise

Analyzer

Automatic analysis in real-time,

Selects optimal NC mode

[Mode A: low to midrange frequency NC] [Mode B: ultra-low frequency NC] [Mode C: wideband NC]

Noise canceling ratio Noise canceling ratio Noise canceling ratio

Frequency Frequency Frequency

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2-4 Noise Canceling Optimization

The shape of the human ear varies subtly from person to person.

When you wear In-The-Ear headphones, there may be a very slight gap between your ear canal and the headphones depending on

the shape of your ear. The size of the gap varies from individual to individual.

Air leaking through this gap affects the loudness of the noise reaching your ears through the gap and this also affects the noise

canceling efficiency.

Noise canceling optimization corrects individual differences in the noise canceling effect by electrically adjusting the size and

spectrum of the noise canceling signal, thereby ensuring the best noise canceling effect for each individual.

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NC OPTIMIZE button for noise

canceling optimization

NC OPTIMIZE

VOLUMESOUND MODE HOLD POWER

Air leakage through gap

Headphone

Ear canal

Wearing headphones

Response

Frequency

Noise canceling signal compensation by Noise Canceling Optimization

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3. High Quality Sound Technology

3-1 High Quality Sound by Digital Sound Enhancer

While the headphones offer exceptional noise canceling performance, the newly developed Digital Sound Enhancer delivers clear,

natural sound. The digital equalizer ensures high quality music reproduction and provides three sound modes suited to the

environment and music source.

Digital Equalizer

The acoustical design of noise canceling headphones generally emphasizes low frequency in order to maximize the effect with

limited electric power, but this impact on the quality of the reproduced sound.

To solve this problem, a digital equalizer is provided on the audio input side.

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The digital equalizer suppresses the impact on the sound quality and delivers high quality sound that gives full play to the intrinsic

performance of the driver unit.

By applying the high-precision, high-sound quality digital equalizing technology accumulated through Sony’s AV amplifiers and

Hi-Fi audiovisual apparatus and adopting the newly developed computation method optimized to the system, it is possible to

reproduce a music source with a sense of realism from deep bass to smooth highs.

Response

Characteristic of acoustical system Characteristic of digital equalizer Total characteristic

Response

Frequency Frequency Frequency

Desired

characteristic

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Three sound modes

Three sound modes suited to the characteristics of the music source ensure easy listening in any noise environment.

 NORMAL:

This mode maximizes the merits of the noise canceling headphones to produce clear, natural sounds.

 BASS:

This mode boosts the bass sounds that give punch to modern dance music.

 MOVIE:

This is the sound mode suited to an AV sound source with wide dynamic range, such as a

movie.

Compression processing increases the volume of quiet sounds such as conversation and

reduces the volume of loud sounds like explosions, thereby adjusting the overall volume to

a listener-friendly level.

Moreover, dialog is made much easier to hear by slight emphasis of the core midrange

frequency, ensuring clear, natural sounds even on a train or plane or in other noise

environments.

15

Movie mode (Image)

Loudness

Explosion

Dialog

Whisper

Input signal

Compression

Output signal

Explosion

Dialog

Appropriate volume

Noise

Signal processing flow



Compression effect

Frequency



Midrange frequency emphasized

Loudness

Whisper

Human voice range

16

3-2 S-Master Full Digital Amplifier

The headphones are equipped with Sony’s retuned S-Master full digital amplifying technology. Digitization right until output

ensures faithful sound reproduction to a degree not achieved with analog amplifiers.

LPF

S-Master power amplifier configuration

Digital signal

Digital logic processor Digital power amplifier

Digital waveform data Audio pulse signal Analog signal

S-Master S-Master

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3-3 Large 16 mm Dynamic Driver Unit

A large 16 mm dynamic driver unit is used as the closed ear receiver.

In addition to the improved canceling of loud/ultra-low frequency environmental

noise, this makes the most of the merits of wideband regeneration and the broad

dynamic range to produce clear, natural sounds with a wide, balanced frequency range.

Integrated Structure of Driver Unit

For the sake of miniaturization, the driver unit has been integrated with the casing. As well as eliminating unwanted air leakage

from the gaps between components, this has reduced unwanted vibration and attained a smooth response in the low range.

MDR-NC300D

13.5 mm driver unit 16 mm driver unit

Conventional unit

(MDR-NC22)

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4. Wearing Comfort

4-1 Vertical In-The-Ear Headphones

The introduction of the large 16 mm driver means that the headphones

are worn with the driver positioned at right angles to the ear canal,

enabling rich bass sounds to be enjoyed with no stress on the ear.

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4-2 Hybrid Earbuds in 7 Sizes

The hybrid silicone earbuds use silicone in a combination of two hardnesses. The hard core maintains the shape of the sound exit

and prevents deterioration of sound quality caused by crushing of the tip. The soft exterior allows better molding to the ear canal,

providing a secure fit and wearing comfort for extended listening. Seven types of earbud are provided to suit different shapes of ear.

Section of earbud

Low hardness silicone

High hardness silicone

Earbud size

Small  Diameter  Large

– ML

(blue)

LL

(purple)

S

(orange)

M

(green)

L

(light blue)

SS

(red)

MS

(yellow)

–

 

High

Height

Low

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Appendix: Total Noise Suppression Ratio

Previously, only the sound pressure loss at a specific frequency was indicated as the canceling performance. However, Sony has

proposed a unit showing the loss of sound “energy” as a closer expression of the listener’s impression.

The total noise suppression ratio (TNSR) of noise canceling headphones is expressed by the following formula.

TSNR = 10 log (P/P

0

)

P

0

= Energy of sound observed at the ear when not wearing headphones

P = Energy of sound observed at the ear when wearing headphones

* The above energy of sound measurements are weighted.

TNSR is the value measured using the noise signal based on a broad spectrum.

As compared with the method of measuring the noise canceling ratio at one frequency, TNSR enables the canceling performance

in the actual usage environment to be more objectively evaluated.

Moreover, the canceling performance in each noise environment can be evaluated using the signals to simulate the spectrum

distribution of real-world noise such as a plane or train.

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Sony MDR-NC300D ユーザーマニュアル

Sony MDR-NC300D ユーザーマニュアル

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