What is noise and vibration analysis?
Noise and vibration analysis, often called NVH (noise, vibration and harshness), is the measurement and signal processing used to find where unwanted sound and vibration come from, how they travel through a structure and how to reduce them. It combines multichannel data acquisition with analysis techniques such as FFT spectra, order tracking, modal analysis and transfer path analysis.
The same toolkit serves vehicle refinement engineers, aerospace test teams chasing resonances, plant reliability engineers diagnosing rotating machinery and health and safety staff assessing worker vibration exposure.
How NVH analysis works
An NVH measurement chain starts with transducers. Accelerometers measure structural vibration, microphones measure sound pressure, tachometers or encoders measure shaft speed, and strain gauges or force sensors capture loads. A data acquisition front end conditions and digitizes these signals simultaneously, so phase relationships between channels are preserved.
Software then turns the time histories into answers:
| Analysis | Question it answers | Typical inputs |
|---|---|---|
| FFT and PSD spectra | Which frequencies dominate? | Accelerometers, microphones |
| Order tracking | Is the problem tied to shaft speed? | Vibration plus tachometer |
| Octave analysis | How loud is it as perceived or regulated? | Microphones |
| Frequency response functions | How does the structure respond to input force? | Impact hammer or shaker plus accelerometers |
| Modal analysis | What are the natural frequencies and mode shapes? | FRFs from many points |
| Transfer path analysis | Which path carries energy to the receiver? | Forces, accelerations, sound |
| Fatigue analysis | How long will the part survive service loads? | Strain and load histories |
| Human vibration weighting | What is the exposure to occupants or workers? | Triaxial accelerometers, seat pads |
The principle is to separate cause from response. A cabin boom that follows engine speed is an order-related source problem. A boom that appears at the same frequency regardless of speed points to a structural or acoustic resonance, which modal testing can identify.
Common applications
- Automotive: powertrain and driveline vibration, road noise and in-vehicle testing for OEMs and suppliers across the Southeast automotive corridor from Alabama to South Carolina.
- Aerospace and defense: flight test vibration and acoustics, structural resonance surveys and shock response analysis for Huntsville-area programs.
- Power generation: turbine-generator and pump vibration monitoring and diagnostics.
- Marine and shipbuilding: ship vibration assessment for Gulf Coast yards.
- Manufacturing: resonance troubleshooting, bearing and gearbox diagnostics.
- Universities: teaching and research in acoustics and structural dynamics.
Choosing the right NVH system
Choose the analysis capability first, then the hardware. An engineer who mainly runs hammer tests and quick diagnostics needs a very different system from a team running 200-channel vehicle programs. The best long-term value usually comes from a platform where the same software runs on small and large hardware, so methods, templates and training carry across projects. Also consider in-vehicle power, synchronization with CAN data and how easily results become repeatable reports.
Manufacturers we represent for noise and vibration analysis
Prosig, a CMTG company, was founded in 1977 by engineers from the University of Southampton’s Institute of Sound and Vibration Research. Its DATS software handles data capture, signal processing and reporting across hardware from the four-channel DATS-solo to the DATS-hyper12, which scales past 1,000 channels. Analysis modules cover NVH, rotating machinery, modal analysis, fatigue and human response to vibration. DATS-CANetic adds vehicle bus data, and PROTOR provides permanently installed vibration monitoring for power plants. Prosig also offers training, rentals and consulting.
Get local application support
Vaughn Associates’ test and measurement engineers can arrange demonstrations, help scope channel counts and analysis modules, and connect you with Prosig’s specialists. Visit engineering support, request a quote, or find your area manager on the territories page.
