Noise Canceling Headphones
降噪耳机
MDR-NC300D
©2009 Sony Corporation Printed in Malaysia
Product Information
产品信息
4-145-681-
31
(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
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
<CXD9952GR>
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
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
10
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.
11
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
12
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.
13
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
Response
Frequency Frequency Frequency
Desired
characteristic
14
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
17
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)
18
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.
19
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
2
目录
1.介绍........................................................................................................... 3
2.卓越的降噪性能................................................................................................. 4
2-1降噪装置的原理............................................................................................. 4
2-2DNCSoftwareEngine........................................................................................ 6
2-3自动AI降噪功能............................................................................................. 8
2-4降噪最佳化................................................................................................ 10
3.高音质技术.................................................................................................... 12
3-1采用DigitalSoundEnhancer的高音质......................................................................
12
3-2S-Master全数字放大器.....................................................................................
16
3-316mm大型动态驱动单元.................................................................................... 17
4.佩戴舒适度.................................................................................................... 18
4-1垂直入耳式耳机............................................................................................ 18
4-27种尺寸的混合耳塞........................................................................................ 19
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