Vehicle Acoustics Strategy

01 Apr 2015 Tweet Tata Motors Research

This post describes the work done during my time at Tata Motors Research Center in Pune. I worked as an Assistant Manager in Human Machine Interface department. Here, I describe my work on studying acoustics inside car and defining strategies to offer best possible audio experience to the user. The work was first used in Tata Tiago/Tigor.

Deccan Chronicle reporting about my work

How did it happen?

Context

I was assigned to the HMI-PAT in ODT division team at Tata Motors RnD in Pune. If the reader is familiar with automotive industry org maps: TML follows a ford style one with some variation due to the acquisition of JLR. This was after Zest and Bolt had launched. The department knew that acoustics needs “quantitative standards” for improvement and benchmarking. We already have instruments to measure spectrum signal strength and audio quality.

Work

I studied various ways to capture and rate the quality of audio output in a contained environment. This also introduced me to the sound chamber. I did several studies using specialized audio workstations used in the audio recording industry. Then I reworked on the testing procedures an used in the audio equipment market. So, I read audio reports and worked on a pipeline to get this data from a car environment. The process was:

• Get data (audio curves like spectrograms etc but with correlation to specific vehicle params) from the car. We used an ASIO compatible Audio Interface and 4 point microphones placed at audio centers of users in the car
• Normalize the data using the sound chamber in two cases (engine running and engine not running).
• Perform the tests on 5 competition cars
• Perform qualitative feedback tests on all 5 cars with users
• Correlate qualitative and quantitative data.
• Suggest improvements in audio curve (audio filter design PoV) and find dependent vehicle build parameters (speaker cavity size, speaker location, speaker size, speaker mounting style (3 bolt/4 bolt/press fit) or vibration absorption unit)
• The filter design was later tested and improved by audio experts once the baseline curve was approved.
• The dependent vehicle build parameters were suggested to design and cavity design teams for adoption in new cars (like Tiago/Tigor/Nexon/Harrier )

Learnings

I learned a lot about org hierarchy and general social skills. On a design point, I was able to design a validated process to do such a kind of analysis for the system. I learned a lot about audio systems from a reproduction point of view. Further, I got acquainted with using ASIO based interfaces by the end of the assignment. I learned about features like SDVC (speed dependent volume control) and its underlying implementation.

How it affected company

The response of the activity was initially cold, but as we started working on details of correlation, we were shocked that our recommendations were adopted in the upcoming programs. A new category for audio analysis was added as a part of benchmarking activity. The detailed process is confidential and is published in the company as a “Work Guideline”.

In Market

The first vehicle to show this was Tiago. The audio system received a superb response. Especially the audio output which had some of Tata and HARMAN’s algorithmic magic. For a feature preferred segment, the audio system was “intelligently” designed to sound like a car from at-least mid-luxury segments. The sales of the car are one of the best in TML’s recent launches and continue to soar. My work may have affected the buying choice of about 6000 customers per month.

A user on a popular car forum, giving feedback on his purchase:

digit magazine liked the music and said:

Selected Media Reports : Deccan Chronicle, Carwale-User Feedback, digit

Skills: Research Methodology, Benchmarking, Design Integration, Acoustics, and Engineering

Cheers,

Rohit