[JustinGray]

I have a new idea for all of you technofiles who want to reduce noise in the insight when driving on rough pavement or bumpy roads.

I have a set of noise canceling headphones which work really well to elminiate low frequencey (such as road noise, and or truck noise) when i wear them in the car (not while im driving of course!)

I took them apart to see how its done. There is a controler box for the noise cancelling circutry inline with the headphone wire, and the microphones it ueses are set into the headphones.

I am using the sennheiser pxc250 headphones.

If i could get the remove the headset, and rewire two new microphones placed well in the cabin, then pipe the output throught my auxilier line in with my ipod, i could possibly use the car speakers to noise cancel the cabin!

I am not ready to runin my 130 dollar headphones yet, but if i find myself with some extra cash, it is definitly a mod i want to try. Expensive airplains have been doing this for some time now, i htink the insight is worthy of such advanced technology!

 

[b1shmu63]

How do they do it in an airplane? Cancelation of noise depends on creating an exact replica of the original sound wave but reversed in phase. I don't believe that a car system is capable of producing the required accuracy. I have been striving for many years to create a technically perfect loudspeaker system using very advanced drivers, so if you are able to do something active I will be very interested to know how you do it.

Our cars have so little sound absorbing material in them that it is relatively easy to get noticeable improvemnts with passive techniques. I'm designing sound cancelling floor mats for my Insight.

 

[Tim Maddux]

It works for headphones because the microphone and speaker are close together and close to your ear. This way the phases can be cancelled between the speaker of the headphone and the eardrum. Trying to do it inside a car won't work, because a) you can't put the mic outside the car and cancel inside and b) the cancellation will only work in some spots in the interior of the car, you'll wind up with all kinds of nodes where the signal strength is doubled instead of zeroed.

 

[JustinGray]

They have made it work in planes with large cabins... king airs and such. I think that it can be accomplished with the proper placement of microphones and the proper tunning of the noise canceling circuit... however you are not the only one who has recomended to me that i might end up with a diffraction pattern of sorts in the car

 

[b1shmu63]

Yup, A similar thing happens with light or RF. It might work at very low frequencies where the wavelength is longer than the inside of the car, but I think you were looking for more than that. Do the headphones work really well in the Insight? Funny, flying a small plane you really should wear headphones for noise control and comunication.

 

[Resist]

Anti noise units were going to replace mufflers on cars. Don't what happened to it, Popular Science did a write up on it years ago.

 

[The Citrus Smoothie]

I know that noise cancellation technology is available in some of the very expensive car market. Don't ask me who.

 

[JustinGray]

the headphones work really well in the car... and in the airplane (commersial) they do a great job of canceling engine noise!

 

[Guest]

Hi All:

___IIRC, there is some type of noise cancellation technology at work in the new HAH during VCM mode?

___Good Luck

___Wayne R. Gerdes
___Hunt Club Farms Landscaping Ltd.
___[email:2v6avltk][email protected][/email:2v6avltk]