Speakerless Cars Could Make Common Annoyance History - AcoustiVision
 

Check out this article from the Toronto Star this weekend:

http://www.wheels.ca/newsFeatures/article/794812

The Short:
"...
In essence, it's a simple concept. Instead of a car being fitted with multiple speakers, its entire interior becomes one big speaker with sound directed inward and at the occupants inside it.

Canadian-based component supplier Magna International has been experimenting with the concept. The company recently exhibited a product it calls AcoustiVision, which turns a car's rear-window glass, behind the rear seat, into a huge sub-woofer.

Magna installed two exciters at the base of the rear-window glass and fed them the sub-woofer signal from an amplifier in the trunk.

The glass, which has a sealant that allows it to vibrate up and down with the bass notes, effectively becomes the membrane of the speaker.

According to Magna product director Greg Rizzo, it's like “sitting inside a subwoofer box.” But — here's the best part — you can't hear it outside the vehicle. ..."




If you start searching "AcoustiVision" on the net, you'll find a similar article and discussions taking place.

What do you guys think about this???

I was looking at this a couple years ago (2004), it is pretty cool. The fidelity is not that good but any surface can be vibrated and it can make noise (sheet metal, glass, dash) or at home (coffee table, windows, TV stand) but it would broadcast out as well as in so the outside of the car would be quite loud. I found it works well on wood, steel and glass but crappy on aluminum.
I was going to use this as part of my installation demo using different panels of the car to talk to the judge as he walks around the car
the basics are available on line and they work similar to bass shakers but can run full audio band (well up to 12K anyway)

But I'm really curious as to how accurate a sound it will reproduce, firstly, and how powerful / loud it will be able to do it at. The average listener doesn't listen to the radio at max volume or at 135db's but us audio guys do.
So ... I'm wondering if it's a fair comparison for the newspaper to talk about "vibrating from the next car."

sounds like a reasonable idea for the masses...enthusiasts will always find a way to integrate better equipment though!

There is some fidelity but not a lot, similar to very good AM radio or an OK FM signal. It does stereo poorly (for instance your windshield is a single 'speaker' only not left or right stereo). It doesn't get all that loud but because it is a planar transducer (the steel or glass used) the sound carries very well. Some frequencies will be louder than others but overall it sounds good

I dont understand how the music wouldn't be audible outside the car if the windsheild is used as a speaker. Unless they were referring to the interior metal being used as a speaker since at least that would have another piece of metal behind it to stop/impede sound transfer.

if the windshield is used as a driver it is equally loud inside as outside. Plastic tends to perform poorly (though hard plastic is better) and padded vinyl dashes are poor

I'll buy into it when I actually see it in production. As for now, I'll take it as an April Fool's joke, even if I'm the fool for not believing it.

That is what I was thinking. What were they referring to with this comment?

I think it was mostly an exaggeration. Inside the car the glass surface is radiating into Pi/2 space (or smaller). Outside the radiation is into something like 2-3 Pi space so the energy dissipates. Have you ever stood behind an open trunk and been unimpressed with the bass, but then you sat in the car without any volume change and it made your hair move? Same thing. Cabin gain is a wonderful thing. I would think exciters on a glass surface would be crapy at higher frequencies.:dunno: