BMW M5

Engine sound symposer systems explained

May 25th 2015 | Benjamin Yong
2015 BMW M5
The BMW M5 features Active Sound Design, which supplements engine noise with simulated sound from the stereo. Photo by Benjamin Yong.


Whether you love or hate Auto-Tune, it makes a lot of recording artists sound better than they might otherwise (cue Britney Spears). In the same vein, engine sound symposers are helping today’s more efficient and noise-isolated engines sound like the gas guzzling, testosterone-infused motors of yesteryear. There are different methods used by automakers to accomplish this task — here are some examples.

Porsche_911_sound_symposer
sae.org


Porsche 911 

A unique and pleasurable aural experience has been as an important quality to Porsche vehicles as any other design characteristic since the 911 was first introduced. Today’s models, however, are bigger, safer and better insulated, and need a little bit of a helping hand in the sound department. To ensure drivers gets the full effect of rising rpms while sitting behind the wheel, Porsche uses an “acoustic channel” that essentially amplifies the vibrations coming from the air intake chamber and transmits them to the interior via a hidden tube. This function is activated by pressing the sport button on the centre console, which opens up a valve inside the tube. 

2015 BMW M5 speakers

BMW M5

Called Active Sound Design, BMW’s sound symposer system takes a more technological approach. In the M5, the stereo and engine management computer are linked so when the large sports sedan accelerates, the speakers play back a simulated engine noise matching the current rpm and speed level. Turning on Sport and Sport+ modes also initiates an increase in sound as you would traditionally expect. BMW has carried Active Sound Design over to other performance-oriented lines like the M3 and M4.

Lexus LFA exhaust tips

Lexus LFA

To convey the perfect driving soundtrack, Lexus joined forces with Yamaha — known for producing everything from motorcycles to pianos — to create the 10-cylinder engine for the LFA. 

When playing a musical instrument, performers hear the delicate changes in volume, tone, and nuances that they produce themselves. Hearing these subtle changes allows performers to make instant revisions as they play the instrument,” reads a description on the Japanese conglomerate’s website. 


“Feedback is equally important when driving an automobile. In this case, feedback refers to how the vehicle responds to the driver’s actions. In a super sports car like the Lexus LFA, providing a high-grade engine sound that changes with even a delicate operation by the driver can contribute directly to the enjoyment of driving.”

No electronic sound processing is used — rather, factors like cylinder firing interval, component thickness and gaps between the engine firewall and cabin were all taken into account during the design.

About the Author

Benjamin Yong is a freelance journalist and communications professional living in Richmond, B.C. He is often found writing about cars and the auto industry, amongst other things, or driving around in his work-in-progress 1990 Mazda MX-5.

Twitter: @b_yong
Instagram: @popuplights