Source Path Contribution (SPC)

Source path contribution

Identifying the sources of the vibroacoustic emissions that we both hear and feel is essential to creating comfortable vehicles.

Machines inevitably make various vibroacoustic emissions that we both hear and feel. However, in order to refine the experience, we need to know more than merely the levels and perceptions experienced by the human. To reduce the correct source of vibroacoustic phenomena, we need to know the contributions from the various sources in detail. And to mitigate the paths that vibroacoustic energy take to us, we need to understand how it travels through the structure and through the air. 

Source-path contribution

During the refinement of development vehicles, engineering questions arise like: “Is it the source that is too loud, or the path that transmits it too easily?” Understanding how vibrations develop from the source into effects at the receiver position requires source path contribution (SPC), or transfer path analysis. This can categorize the effects perceived at the user as airborne or structure-borne, and drill progressively deeper into their origins, tracing them back to the root cause, such as a specific engine mount.

Time domain

For effective SPC on vehicles, it’s important to be able to analyse transient events, such as run-ups and run-downs. It’s also very useful to be able to replay safely recorded signals and modify them to simulate design changes. With time-domain SPC software, you can listen to noise paths and results, and modify them to set target levels at the detail of individual component source strengths or transfer paths. The software can also act as a bridge to CAE models, combining test data and CAE designs to produce hybrid models that highlight design possibilities.

SPC offers a bridge between real-world experimental data and analytical data generated from CAE models. Combine test and CAE results in SPC to produce hybrid models or virtual prototypes. Use Insight to experience the results of experimental, hybrid or purely analytical CAE-based SPC data through interactive playback and analysis of the results.

System suggestion

Integration of CAE and test data system overview

For SPC Integration of CAE/Test, a typical configuration consists of SPC Viewer (7798-A), Time-domain SPC (7798-E) and Insight 8601-S. We also highly recommended proper sound playback hardware including sound card ZH-0677, headphone amp ZE-0769 and headphones HT-0017

DTS CAE Auditioner (8601-X) is an optional model for Insight Type 8601-S and can quickly incorporate source strengths and transfer functions from common CAE programs into the Insight evaluation tool.

How will each component contribute to the overall sound of a product? How can you tell where the sound is coming from? How does it travel to where you hear it? And what can you do to improve the sound of the vehicle? Whether assessing the contributions of an engine on a test bed, or identifying operational contributions on the road, Time-domain Source Path Contribution (SPC) allows you to assess transfer paths and contributions to quickly evaluate the noise and vibration perceived by vehicle occupants. Our unique time-domain technology allows you to listen to and compare data sets back-to-back, and assess the effects that developments will have on the final products through SPC models. The system can also inspect data in the frequency domain, giving great flexibility. 

System suggestion

Time-Domain Source Path Contribution system overview

A typical configuration consists a PULSE data acquisition system with SPC viewer (7798-A), Time domain (7798-E) and Insight 8601-S software and LAN-XI hardware. We also highly recommended proper sound playback hardware – sound card ZH-0677, headphone amp ZE-0769 and headphones HT-0017. Accelerometers, microphones, hammers, etc., are also needed.

SPC works with data acquired with PULSE data acquisition systems as well as most other data acquisition systems and most CAE solutions.