I took a long road trip the past weekend and while the TCH was quiet the tires made the cabin a bit noisy at 70mph.

Tire whine seems to be an excellent application for noise cancellation technology. I own a Sony NWZS716FRNC with noise cancellation built in so I was wondering could I use this to provide some noise cancellation.

I was thinking of getting headphone splitter with 1 output to the TCH Aux and the other to the Sony headphones with the microphones in them.

Theoretically (at least in my mind) this would work.

Has anybody tried this yet?

 

Randon origin source noise cancellation is a function of the location of the "receptor" the individual person's ear. You MUST do the computation accordingly.

Noise cancellation is also possible at the point of origin, anti-noise engine mufflers, for instance.

 

I don't think that Tire noise is random. the noise of hitting a pothole would be random and therefore not a good candidate for cancellation from how I understand it. There is definitely a tonal frequency to tire whine similar to that of a jet engine.

I'm not sure that unless the microphones are right next to my ears the cancellation won't be effective. Perhaps if i suspended the mics in the center of the passenger space that would be effective enough?

What would be different than the application of this technology in the GM Equinox ? ( http://www.autobloggreen.com/2009/06/10/noise-cancelling-speakers-help-2010-chevy-equinox-get-1-mpg/).

In the Equinox case the microphones are in the headliner.

The main reason I'm not just trying this out experimentally is that there is a proprietary connection used by the headphones that a Y jack would need to support. Perhaps Sony has a splitter that would send the cancellation to the AUX with reverse waves intact.

The Sony noise cancellation occurs in the device and is fed back to the drivers.

I appreciate any thoughts you have on this.

 

I never noticed any noise.

Are you over inflating your tires?
TireRack.com

 

Random origin....

Origin of noise being random....

 

Noise cancellation works on the principle of sending a wave with exactly opposite polarity, so timing is crucial. Easy to do on the headphones, but much more difficult with speakers, why? Because sound travels with speed of around 360 meters per second (give or take depending on altitude, temp., etc.) Lets say rear speakers are about 2 meters away from your head so by the time the sound reaches your ear, it is delayed by 1/180 sec. Assuming everything else is perfectly tuned and there is no delay in electronics, perfectly tuned opposite wave coming from headphones will work but delayed by 1/180sec wave coming from speaker will be most likely be out of phase, unless you put your speakers at the same position as the noise (tires), rather impossible, or you can adjust timing of the wave which your headphones probably don't have. BTW, I found noise canceling headphones waste of money. The noise is diminished by the fact of having the headphones covering my ears much more than the noise cancellation technology itself IMO. This technology could have big benefit for example for a jet mechanic, where jet engine noise could be canceled, so he can hear somebody talking to him, but I still see them using hand signals instead. As for passenger on the plane for example, I rather have heavy noise reducing padding on my headphones instead of noise cancellation electronics. Maybe it was just the headphone set I have that's not working too well, but so far I'm not impressed. Also low roll resistance tires should generate lower noise, me think, so I would start there first, with generating lower noise to begin with.

 

I'd suggest adjusting tire pressure to the proper (manufacturer's suggested) pressure. Get on the highway, do 70 MPH and see if you notice a difference in tire noise.
If so, you found the culprit.

 

I didn't mean to imply that there was excessive noise from my tires. They are properly inflated LRR tires and really are quiet compared to other tires I have used.

As you increase your speed the amount of noise increases, no matter what you do. It's a combination tire, wind and engine noise that contributes to the overall rise. I think the combination of sound does not seem random and could be lowered using noise cancellation technology.

I use my Sony player to reduce the noise while I am mowing the lawn and it is very effective in allowing me to listen and enjoy music at relatively low volumes. When I switch the NC effect off, the music is overcome by the noise of the mower. I was skeptical about the possible effectiveness until I tried it and was convinced.

I realize that there could be a timing issue causing the reverse phase wave to be out of sync, but am encouraged by the previous Equinox and others cars that have used the technology successfully. I think that the size of the waves are a factor and would work better with mid and low frequency waves. If it only works half as effectively as when I'm cutting the grass it would be worth it.

 

As others have noted, canceling tire noise via speakers and microphones is technically difficult. See "Zone" cancellation in my IEEE paper:

http://doctord.webhop.net/Pubs/POTENT.htm

I find that my Nokian WRg2 tires (they are LRR tires) are reasonably quiet at highway speeds whereas the earlier Nokian WR tires (also LRR) were quite noisy.

JeffD

ps. Tire noise has both periodic and random noise components. It varies as a function of the tread material, tread design, and road surface.

 

My "practice"...

My '01 F/awd RX300 runs on nice and quiet, comfortably riding, Bridgestone Turanza "summer use only" tires throughout the year. I "deposited" an entire spray can of undercoating inside each wheelwell. I regularly "reseal" the window and door rubber gaskets with a light coating of NAPA SilGlyde. When teh A/C is enabled (mostly not.) I must often run it FULL OUT, Max cooling, and then use the blower speed, LOW blower speed, to moderate the cooling level. This latter effort avoids the A/C reheat/remix mode and therefore also results in slight FE improvement.