Fraunhofer Institute for Machine Tools and Forming Technology (IWU), in collaboration with development partner EMEC Prototyping GmbH, has introduced a specialized acoustic testing and development program aimed at improving sound quality in premium e-bikes and high-performance bicycles.
Unwanted noises such as rattling, clicking, and high-frequency vibrations can significantly affect rider comfort and influence perceptions of product quality. To address these issues early in the development cycle, has installed a newly developed acoustic test rig within an anechoic chamber at its Dresden facility. The setup enables highly precise acoustic measurements under controlled conditions, helping manufacturers accelerate product refinement and time to market.
Focus on Acoustic Quality from the Prototype Stage
Sound and vibration play a key role in purchasing decisions, particularly in the premium e-bike segment. A smooth, quiet riding experience is widely regarded as a marker of quality, while tonal noises and vibrations are perceived negatively.
The joint program combines advanced test rig technology with expertise in acoustic measurement and analysis. Manufacturers can identify and address noise sources during the prototype phase, reducing the risk of issues emerging late in development or during series production.
Realistic Testing to Prevent Late-Stage Surprises
Unlike conventional test rigs that prioritize durability and structural testing, the new system is specifically designed to analyze noise generation and transmission. Developed by EMEC Prototyping and validated by Fraunhofer’s acoustic specialists, the rig ensures high measurement accuracy and reproducibility.
It can simulate real-world riding scenarios, including defined ground excitations, drive unit load changes, and targeted vibration inputs. Both complete bicycles and individual components—such as drivetrain systems—can be tested. The system also allows for testing under realistic pedaling conditions, including scenarios where a rider actively pedals during measurement.
High-resolution sensors capture both airborne and structure-borne sound, while the decoupled test environment enables detection of subtle acoustic effects. This allows engineers to pinpoint root causes such as dynamic excitation, resonance, or structural design issues.
Data-Driven Development and Benchmarking
The test rig provides consistent and comparable data to support development, benchmarking, and pre-series validation. Fraunhofer IWU applies acoustic analysis across the full causal chain—from excitation and transmission to sound radiation—ensuring that both symptoms and underlying mechanisms are addressed.
To align technical measurements with real-world riding perception, additional evaluation methods are available, including:
- Binaural head technology, which measures sound at the rider’s position using a dummy head to replicate human hearing.
- Pass-by measurements for product comparison and exterior noise assessment.
- Sound power determination according to standardized or project-specific requirements.
- Vibration analysis on frames and components to evaluate tactile comfort and structural behavior.
Scientific Methods to Identify Noise Sources
Fraunhofer IWU uses structured acoustic engineering approaches to identify and mitigate noise at its source. Many unwanted sounds originate from dynamic forces generated by electric motors or gearboxes, which travel through interfaces into the frame and radiate as airborne noise.
Key analytical tools include:
- Transfer Path Analysis (TPA), which identifies and quantifies how vibrations and noise travel from their source to the rider.
- NVH (Noise, Vibration, and Harshness) analysis, focusing on frequencies generated by electric drive systems that affect acoustic comfort.
Fraunhofer IWU’s acoustics team in Dresden is inviting e-bike manufacturers, component suppliers, and other electric mobility stakeholders to engage with the new testing and development program.
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