素早い回答
Automotive cabin noise mainly reaches occupants through two transmission paths: airborne noise and structure-borne noise. Airborne noise is typically controlled using porous sound absorbers and barrier systems. Structure-borne noise usually requires damping, vibration isolation, decoupling, and structural optimization. PP/PET fibrous automotive acoustic materials are mainly used to absorb airborne sound and reduce interior sound reflection. They are commonly applied in roofs, headliners, doors, firewalls, floors, trunks, pillars, and interior trim. In electric vehicles, reduced engine masking makes tire noise, wind noise, and electric-drive high-frequency noise more noticeable, increasing demand for lightweight broadband acoustic materials.
How Automotive Acoustic Materials Improve Cabin Comfort
For automotive OEM and Tier 1 engineers, cabin comfort is not simply about reducing a few decibels.
Effective automotive acoustic engineering starts with three fundamental questions:
- ノイズはどこから来ますか？
- How does it travel into the cabin?
- Which material or structural solution is best suited to control it?
In automotive NVH engineering, noise generally reaches the passenger compartment through two primary paths:
- 空気伝播騒音
- Structure-borne noise
Understanding the difference between these two transmission paths is essential when selecting automotive acoustic absorbers, insulation materials, damping layers, decouplers, and multilayer acoustic systems.
素早い回答
Automotive acoustic materials improve cabin comfort by controlling sound and vibration through several different mechanisms.
Porous fiber materials are mainly used to absorb airborne sound.
Damping materials help reduce panel vibration.
Barrier layers reduce sound transmission.
Decoupling materials help limit vibration transfer between structures.
In real vehicle applications, these functions are often combined into an integrated acoustic package rather than relying on a single material to solve every NVH problem.
- What Is Automotive NVH?
NVH stands for:
- ノイズ
- 振動
- 厳しさ
Together, these factors strongly influence how drivers and passengers perceive vehicle comfort and quality.
ノイズ
Noise refers to the sound heard by vehicle occupants.
Typical automotive noise sources include:
- Tire and road noise
- 風切り音
- エンジン音
- Electric motor noise
- ギアノイズ
- HVAC noise
- Cooling system noise
- Body-panel radiation
Different frequency ranges create very different subjective impressions.
Low-frequency noise may be perceived as:
- 好景気の
- ゴロゴロ
- droning
Higher-frequency noise may be perceived as:
- 泣き言
- シーッという音を立てること
- sharp tonal noise
- electric motor high-frequency noise
This is why overall sound pressure level alone cannot fully describe cabin acoustic quality.
振動
Vibration originates from mechanical excitation.
代表的なソースは次のとおりです:
- Tire-road interaction
- サスペンションの動き
- Powertrain excitation
- 電気モーター
- ギアシステム
- 構造共鳴
These vibrations can travel through:
- サスペンション部品
- サブフレーム
- シャーシ
- ボディパネル
- Seat rails
- ステアリングシステム
Some vibrations are directly perceived by occupants.
Others excite body panels, which then radiate sound into the cabin.
厳しさ
Harshness refers more to the subjective perception of vehicle vibration and sound quality than to a single physical parameter.
例としては以下の通りです：
- Strong impact when driving over road irregularities
- Excessive low-frequency vibration
- Cabin booming at specific vehicle speeds
- Unpleasant structural resonance
The objective of good NVH engineering is therefore not to eliminate every sound.
It is to control undesirable acoustic and vibration energy.
- How Does Noise Enter the Vehicle Cabin?
From a transmission-path perspective, automotive cabin noise can generally be divided into two major categories:
空気伝播騒音
(NAIST) と
構造伝播音
These two mechanisms require different control strategies.
- What Is Airborne Noise?
Airborne noise is sound energy that primarily travels through the air before reaching the passenger compartment.
For example, tire-road interaction generates acoustic energy around the wheel area.
Part of that sound travels through air and can enter the vehicle through the floor, wheel arch, doors, or other body structures.
Similarly, HVAC blowers generate sound that travels directly through air ducts and the cabin.
Typical airborne noise sources include:
- 風切り音
- Tire radiation noise
- HVAC noise
- 冷却ファンの騒音
- Exterior traffic noise
- Some electric motor noise
- Some powertrain noise
Once airborne sound enters the cabin, it can also reflect repeatedly from interior surfaces.
If the vehicle interior has insufficient sound absorption, sound energy may continue reflecting from areas such as:
- ルーフ
- 立て役者
- ドア
- ダッシュボード
- 床
- Trunk（幹）
This increases the acoustic energy perceived by occupants.
That is why sound-absorbing materials are widely used throughout the vehicle interior.
- How Do Fibrous Automotive Acoustic Materials Absorb Sound?
PP/PET fibrous acoustic materials are typical porous sound absorbers.
When a sound wave enters the fiber network, air particles move through a complex porous structure.
During this process, acoustic energy is reduced through mechanisms such as:
- Friction between air and fibers
- 粘性損失
- Thermal exchange
- Energy dissipation caused by airflow through the porous network
A small portion of the acoustic energy is ultimately converted into heat.
As a result, less sound energy is reflected back into the cabin.
This is the basic principle behind fibrous automotive acoustic absorbers.
- Why Is Thickness Alone Not Enough?
A common assumption is that thicker acoustic material always performs better.
In reality, automotive sound absorption depends on many parameters, including:
- 厚さ
- 坪量
- 密度
- 繊維径
- 繊維構造
- 気孔
- 気流抵抗
- 圧縮比
- 設置条件
- Target frequency range
One of the most important parameters is airflow resistance.
If a material is too open, sound can pass through easily, but interaction between the moving air and the fiber network may be insufficient.
If a material is too dense, too much sound may be reflected at the surface instead of entering the porous structure.
High-performance acoustic materials therefore require an appropriate balance between:
Porosity, fiber structure, and airflow resistance.
- What Is Structure-Borne Noise?
Structure-borne noise begins as mechanical vibration transmitted through the vehicle structure.
典型的な例は次のとおりです。
Road excitation
↓
タイヤの振動
↓
サスペンション
↓
サブフレーム
↓
Vehicle body
↓
Body-panel vibration
↓
Sound radiation into the cabin
The final sound may still be heard through the air, but the original transmission path was structural.
This is the key difference between structure-borne and airborne noise.
- Why Can Acoustic Fiber Not Solve All Structure-Borne Noise?
This is one of the most important distinctions in automotive acoustic engineering.
Porous acoustic fiber is mainly designed to absorb airborne sound energy.
If the main problem is strong vibration of a door panel, floor panel, wheelhouse, or another structural component, adding more acoustic fiber alone will not eliminate the root cause.
Structure-borne noise typically requires a combination of several control methods.
制振材
Damping layers are used to reduce vibration amplitude in metal or composite panels.
代表的な応用分野は次のとおりです。
- Door outer panels
- フロアパネル
- Wheelhouse areas
- Trunk panels
- 車体板金
Decoupling Materials
Decoupling layers help reduce mechanical coupling between structures.
They are also important in multilayer acoustic systems where a compliant layer is required between a barrier and the vehicle body.
バリア材
Barrier layers are used to reduce sound transmission.
They typically rely on higher surface mass or multilayer construction to improve transmission loss.
吸収材
Absorbing layers reduce airborne sound energy once that energy reaches the cabin or acoustic package.
In practical vehicle design, these functions are often combined as:
Damping + Decoupling + Barrier + Absorption
- Airborne and Structure-Borne Noise Are Often Coupled
In real vehicle NVH problems, airborne and structure-borne mechanisms are not completely independent.
具体的な例を挙げますと、以下の通りです。
Road excitation first generates mechanical vibration.
That vibration travels through the suspension and body structure.
The body panel is then excited.
The vibrating panel radiates sound into the cabin air.
The full path may therefore be:
Road Excitation
↓
Structure-Borne Vibration
↓
Body-Panel Vibration
↓
Airborne Sound Radiation
↓
Passenger Perception
For this reason, OEM NVH engineers do not simply ask whether a problem is airborne or structure-borne.
彼らは次のことを理解する必要があります:
- Which source is dominant?
- Which transfer path contributes most?
- Which frequency range requires improvement?
- Different Frequency Ranges Require Different NVH Strategies
No single material can effectively solve every noise problem across the entire frequency spectrum.
Different frequency ranges typically require different engineering strategies.
低頻度
Low-frequency problems are often related to:
- Body modes
- 構造的な振動
- パネル共振
- Suspension excitation
- Powertrain excitation
Severe low-frequency issues usually cannot be solved by lightweight porous absorbers alone.
Typical solutions may include:
- 構造最適化
- 減衰
- 防振
- Mount optimization
- Body stiffness optimization
中周波数
Mid-frequency noise often requires a combination of:
- 減衰
- デカップリング
- バリア性能
- 吸音
Mid-to-High Frequency
Fibrous porous absorbers are particularly useful in the mid-to-high-frequency range.
Their acoustic performance can be tuned by adjusting:
- 厚さ
- 坪量
- 繊維構造
- 気流抵抗
This is why automotive acoustic materials should not be evaluated by a single absorption value.
The full absorption curve across the relevant frequency range is far more meaningful.
- Why Do Electric Vehicles Change Acoustic Material Requirements?
Electric vehicles do not make NVH engineering easier.
They change the noise spectrum.
In internal-combustion vehicles, engine noise creates a relatively strong background sound that can mask other noise sources.
In electric vehicles, this masking effect is reduced.
As a result, previously less noticeable sounds can become more prominent, including:
- タイヤノイズ
- 道路騒音
- 風切り音
- 電気モーターの甲高い音
- ギアノイズ
- Inverter tonal noise
- HVAC noise
- Cooling-system noise
EV acoustic design therefore places greater emphasis on:
- 広帯域吸音
- Mid-to-high-frequency noise control
- 軽量化
- 材料の統合
- Local acoustic optimization
- Why Are Lightweight Acoustic Materials Becoming More Important?
Adding more NVH material can improve acoustic performance.
However, additional material also increases vehicle mass.
This can directly affect:
- 車両重量
- エネルギー消費
- EV走行距離
- 製造コスト
- 組み立ての複雑さ
For this reason, the goal is not simply to add more material.
The objective is to achieve the required acoustic performance with lower weight and less installation space.
This is one of the main advantages of fibrous automotive acoustic materials.
調整することで：
- 繊維組成
- 坪量
- 厚さ
- 密度
- 層構造
the material can be optimized for different locations and vehicle platforms.
- Where Are Automotive Acoustic Materials Used?
Different vehicle zones have different acoustic requirements.
Roof and Headliner
典型的な懸念事項は次のとおりです。
- 風切り音
- Cabin reverberation
- Rain impact noise
- 広帯域吸音
Low weight is particularly important in this area.
ドア
Door systems may be affected by:
- Exterior airborne noise
- Door-panel vibration
- Cavity resonance
- Speaker interaction
For this reason, door acoustic systems often require both absorption and structural vibration control.
Firewall and Dashboard Area
This is one of the most important NVH control zones.
Typical noise sources include:
- Powertrain noise
- 道路騒音
- HVAC noise
- Structural radiation
Multilayer acoustic systems are commonly used here rather than a single absorber.
床
典型的な懸念事項は次のとおりです。
- Tire-road excitation
- サスペンションノイズ
- Underbody noise
- 構造的な振動
Common floor acoustic systems may include:
Absorber + Decoupler + Barrier
with localized damping where necessary.
ホイールアーチ
The wheel area is one of the most important noise sources in the vehicle.
Acoustic materials used here may need to address:
- タイヤノイズ
- Road excitation
- Stone impact
- 水への暴露
- 汚染
Therefore, material selection must also consider:
- 耐湿性
- 耐久性
- 汚染耐性
Trunk（幹）
Rear-wheel and rear-body excitation can introduce significant acoustic energy into the trunk cavity.
Absorptive materials can reduce cavity reflection and help limit further sound propagation toward the passenger compartment.
Pillars and Body Cavities
Vehicle cavities can act as acoustic transmission paths.
Proper use of:
- Acoustic absorbers
- Cavity fillers
- シーリングシステム
can reduce sound transmission through these areas.
- Which Material Parameters Should OEM Engineers Evaluate?
Automotive acoustic materials should not be evaluated only by whether they are “good at absorbing sound.”
A more complete evaluation should include the following parameters.
音響パフォーマンス
- 吸音率
- Frequency-dependent absorption curve
- 気流抵抗
- 空気流抵抗率
物理的特性
- 厚さ
- 坪量
- 密度
- 圧縮回復
- 寸法安定性
環境パフォーマンス
- 耐熱性
- 耐湿性
- 耐老化性
自動車の要件
- 可燃性
- VOC performance
- 臭気
- 曇り
- 材料の互換性
処理性能
- ダイカット
- 熱成形
- ラミネート加工
- 自己接着バッキング
- アルミ箔ラミネート加工
- Complex-shape conversion
サスティナビリティ
- 軽量化
- リサイクル性
- 材料の簡素化
- リサイクルされたコンテンツ
- Why Is Installation Condition as Important as Material Data?
The same acoustic material can perform very differently under different installation conditions.
重要な要素は次のとおりです。
- エアギャップ
- 圧縮
- Backing surface
- 設置場所
- ジオメトリ
- Edge leakage
- 隣接材料
- 多層構造
For example, a material with a free-state thickness of 20 mm may behave very differently if compressed to 8 mm after installation.
Compression can change:
- 気孔
- 気流抵抗
- Effective thickness
- 音響性能
This is why automotive acoustic materials should not be evaluated only from laboratory datasheets.
Final installed condition must also be considered.
- Transulate™ Automotive Acoustic Materials
翻訳する™ is a PP/PET bicomponent fiber material series developed by SINOYQX for automotive acoustic and thermal-management applications.
The material is designed for applications including:
- Automotive sound absorption
- 断熱材
- Lightweight acoustic packages
代表的な応用分野は次のとおりです。
- ルーフ
- 立て役者
- によって
- ダッシュボード
- ファイアウォール
- 床
- Trunk（幹）
- 柱
- インテリアトリム
Depending on the project, key material parameters can be customized, including:
- 坪量
- 厚さ
- 密度
- 繊維構造
- 積層構造
- How to Select the Transulate™ Series
翻訳する™ LT Series
Typical basis weight:
100～200gsm
標準厚さ:
10〜20 mm
Suitable for lightweight applications such as:
- ルーフ
- 立て役者
- によって
- 柱
- インテリアトリム
The key focus is low weight.
翻訳する™ AP Series
Typical basis weight:
300～500gsm
標準厚さ:
20〜30 mm
こんな方へ：
- ファイアウォール
- によって
- 床
- Trunk（幹）
- General acoustic packages
Transulate™ HP Series
Typical basis weight:
600～900gsm
標準厚さ:
30〜50 mm
Suitable for applications requiring higher sound absorption and where more installation space is available.
- What Additional Processing Options Are Available?
Depending on OEM and Tier 1 project requirements, Transulate™ can be supplied or converted as:
- ロールズ
- シート
- ダイカットパーツ
- Self-adhesive parts
- Aluminum-foil laminated products
- Nonwoven-faced products
- 多層複合材料
- カスタマイズされた厚さ
- Customized basis weight
The final acoustic structure should be selected according to:
Target Frequency + Installation Location + Available Space + Weight Target
- Automotive Acoustic Engineering Is Moving from Material Selection to System Design
The future of automotive NVH development is not simply about identifying which absorber has the highest sound absorption coefficient.
より重要な質問は次のとおりです。
- Which noise source is dominant?
- Which transfer path is most important?
- Which frequency range needs improvement?
- Which material is best suited to the location?
- How can the target performance be achieved with less weight?
A more effective development process is:
Identify the Noise Source
↓
Analyze the Transfer Path
↓
Define the Target Frequency
↓
Select the Control Strategy
↓
素材を合わせる
↓
Validate at Component Level
↓
Validate at Vehicle Level
This is how material performance can be converted into real cabin comfort.
結論
Vehicle cabin comfort is not controlled by a single material.
Airborne noise is mainly managed through:
Sound absorption and sound insulation.
Structure-borne noise generally requires:
Damping, vibration isolation, decoupling, and structural optimization.
Fibrous automotive acoustic materials play an important role in reducing airborne sound energy, limiting cabin reflections, and improving mid-to-high-frequency acoustic performance.
This becomes even more important in electric vehicles, where reduced engine masking makes tire noise, wind noise, and electric-drive tonal noise more noticeable.
At the same time, vehicle manufacturers continue to reduce weight.
For this reason, the next generation of automotive acoustic systems is not about adding more material.
それは約です：
Using the right material, in the right location, for the right frequency range.
Transulate™ automotive acoustic materials can be customized according to OEM and Tier 1 requirements, including application location, target frequency, thickness, basis weight, lamination structure, and annual demand.
よくある質問
What is the difference between airborne noise and structure-borne noise in a vehicle?
Airborne noise travels primarily through air, such as wind noise, HVAC noise, and some tire noise.
Structure-borne noise begins as mechanical vibration transmitted through the suspension, body, or other structural components before being radiated as sound.
Can automotive acoustic fiber directly reduce structure-borne noise?
完全ではありません。
Porous fibrous materials primarily absorb airborne sound.
If the main problem is structural panel vibration, additional damping, isolation, decoupling, or structural optimization is usually required.
What are the most important parameters for automotive sound absorbers?
Important parameters include thickness, basis weight, fiber structure, airflow resistance, absorption performance across frequency, compression condition, installation gap, and target frequency range.
Why are lightweight acoustic materials important for electric vehicles?
Electric vehicles have less engine masking noise, so tire noise, wind noise, electric motor noise, and other high-frequency sounds become more noticeable.
At the same time, lower vehicle mass helps improve energy efficiency and driving range.
Where can Transulate™ automotive acoustic materials be used?
Typical applications include roof, headliner, doors, firewall, dashboard, floor, trunk, pillars, and interior trim.
The final material specification should be selected according to installation space, target frequency, basis weight, and thickness requirements.