Every new car comes with a pretty stereo these days and the expensive stuff in the luxury segment is often loaded up with monster high-performance sound systems.
These have woofers and tweeters in every corner of the car and probably a couple of huge sub-woofers taking up half the trunk. As well as providing the potential for hearing loss, all this equipment takes up space, adds weight to the vehicle and draws plenty of juice.
At the University of Windsor, there's a project supported by the Auto21 research group and Magna International that has a professor and some grad students perfecting a system that scraps the speakers altogether and uses the windshield – or the rear window if you prefer – as the source of sound.
I couldn't believe that a hard sheet of glass could produce quality sound, especially the thump, thump, thump of giant sub-woofers until I sat in the car. It sounded amazing and the huge speaker boxes were gone.
Colin Novak leads the project.
Vaughan: Why try to turn a windshield into a speaker system?
Novak: There are several advantages of this technology.
It's a lot lighter than a conventional sub-woofer system and it also uses a lot less electrical power.
Well I heard that “sub-woofer” coming off the glass and it shook my bones.
Right now, we're just working on putting the sub-woofer on the windshield although the technology can certainly be expanded – and we are looking into it – to a more full-range speaker.
But for now, it's just the low-frequency component of the speaker system. Ours is targeted between 10 and 120 Hz. We're hoping to get it up to about 180 Hz where a conventional sub-woofer in your car only goes up to about 90 Hz.
By being able to get into a higher frequency with our technology, it means the other speakers in the car can be downsized.
And the reason for doing this is weight reduction?
Yes, it's to make cars more fuel-efficient in the long run by reducing weight and electrical power consumption.
Reducing electrical power is very important in newer electrical vehicles and hybrid electric vehicles where you're using the electricity to make the vehicle go.
And the windshield is just a stock windshield. There's nothing special about the glass.
It's a stock windshield. The only thing we've added is the actuators that are exciting the glass.
And we had to develop seals around the glass that are a little bit more pliable to allow that glass to move up and down.
The amplifiers to drive the exciters are actually smaller and more efficient that a conventional stereo amplifier. A glass is a very stiff membrane compared to a speaker membrane.
It's very unconventional to use something like this for this type of application, but it doesn't mean that we can't do it.
We also have to bring the cost down, but we're not really using anything in the way of new technology – for example, the drivers that we're using to excite the glass are based on technology that's used in other areas. It's just being applied for a completely different purpose here.
You're an audiophile. You have a very good ear. Is this as good as an expensive stereo system that you put in expensive cars?
It's getting there. That's the whole idea.
Our area of research is of Psycho Acoustics, which is the study of the perception of noise. So our focus is not only to produce the sound, but to tune that sound such that it sounds the best that it can.
Magna owns the technology or the intellectual property and we're working with Magna through Auto21 on how to improve the system and bring it to the point where it would be marketable.
You can tune anything. For you, it's just physics isn't it?
Absolutely. That's all it boils down to.
We have our physical constraints and we just manipulate it using physics to get what we want out of the system.
For me, it works, especially if you can replace all the speakers with the windshield.
That is the idea down the road.
Because we're exciting the glass with two different exciters we can localize where the sound is being produced on the windshield to make it sound like there's two different drivers generating the sound when in fact it's just one big sheet of glass.
Michael Vaughan is co-host with Jeremy Cato of Car/Business, which appears Fridays at 8 p.m. on Business News Network and Saturdays at 2 p.m. on CTV.
