Sounds are easy to measure, but at the same time our experience of sound is highly subjective; not least, our expectations of how a Scania should sound. And that’s what makes acoustic engineer Anna Färm’s work so fascinating.
Anna Färm has a trained ear and is an experienced listener. She always wears earplugs in noisy environments to protect her valuable ‘instrument’.
“In my profession, it is important to avoid hearing problems,” she explains.
As a Technical Manager for Scania’s acoustics department, one of Färm’s jobs is to develop testing and verification methods. But at the moment, the focus is on ensuring that the new generation trucks meet the specific sound requirements (Scania acousticians prefer trucks to sounds rather than ‘noise’ when it comes to acoustics). More intense listening lies ahead, with Scania’s powertrain next on the list.
Electric vehicles will mean new acoustic conditions
However, in the longer term, the work of Färm and her colleagues is going to change. In line with the move towards electric vehicles, acoustic conditions will become a bit different.
“With electrification, it will be more about sound quality than noise levels,” says Färm.
“The quieter powertrains of electric vehicles will make us notice noises in the cab and outside the truck much more. When we no longer have the powertrain acting as a sonic mask, other sounds will start to become annoying.”
This will mean the acousticians’ work will be more focused on ‘softer’ issues.
“Sometimes sound measurements are only blunt instruments; one has to listen to and feel the sound, which we can do in our listening studio.”
For five years, Anna Färm was attached to Scania R&D as an industrial PhD student, a placement that ended with the completion of her dissertation in 2016. The focus of her research was whole-vehicle acoustic simulation.
“To a certain extent, I began applying the results to simulations and to work on concepts for encapsulation. There I found a use for the practical elements of my research.”
course prompted Anna’s interest in acoustics
Färm became interested in acoustics when she took a course in sound and vibration at the Royal Institute of Technology’s Department of Vehicle Technology in Stockholm.
“I thought it seemed like an exciting area. It’s very complex, with a lot of exciting physics and maths…and it’s a lot of fun, too.”
Acoustics is a broad field, with many different areas of work
Acoustics covers a wide variety of jobs – ranging from building concert halls to planning pubic construction projects to ensure a good sound environment; the latter is an area that Färm worked in before her research career.
“As Technical Manager, I am responsible for the performance management of our acoustics. My job is to ensure that noise certification standards are achieved and that the requirements for cab noise are met, but also that Scania has a sound that is attractive and competitive when it comes to customer sales.”
Her work also includes informing people about the importance of acoustics.
“It’s certainly not the first thing people think of when they consider how trucks are built, but a lot of what we do can affect how the vehicle sounds.”
A Scania truck should not sound ‘tinny’
The sound must be in harmony with the function. When you put your foot on the accelerator, you should hear and feel the right things. In a cheaper car when the door opens and closes it feels and sounds ‘tinny’. A Scania should never sound tinny.
“We really notice when the sound is bad, not when it’s good,” says Färm.
“We also hear sound in different ways. We can also become so used to a sound that we stop noticing it, as happens with people who live by the sea. We also tend to focus on a certain sound – the acoustics in the churches sound good because we expect them to.”
As we said at the outset, sound is subjective, and can be experienced in many ways. The most common question that Färm is asked is which speakers to choose.
“My answer is that you should first decide your price range and then never listen to more speakers that are more expensive than the ones you bought!”