Acura Using Bose Noise Cancellation

[jdandy]

Introduced in the '05 Acura RL, and now available in all Acura models, active noise cancellation is said to reduce outside noises and engine noises inside the vehicle cabin. The Bose sound systems in the Acura models use the same type of 180 degree phase shifting as the Bose Quiet Comfort headphones use. Stragically place microphones inside the vehicle monitor noise levels, and using software, a combination of low and higher frequencies are actively canceled. The new Active Sound Control system is much advanced over Acura's previous Active Noise Cancellation system. Where the original noise control system dealt with the elimination of low sound pressure entering the cabin, the new Active Sound Sontrol system has a much broader range including the elimination of unwanted high frequency noise.

Would this type of noise cancellation process be more appealing to you than controlling cabin interior noises with advanced structural and sound insulation designs and materials?

[Still-One]

Originally Posted by jdandy

Would this type of noise cancellation process be more appealing to you than controlling cabin interior noises with advanced structural and sound insulation designs and materials?

It is appealing to Honda and every other auto maker since sound insulation adds weight. Weight is just about the biggest enemy of the auto companies. MPG!!

[JJinID]

I think it would be interesting to apply this type of noise cancellation in combination with an active Room Perfect / Audessey type solution in an automobile (have active microphones in various places in the car that send data to a processor that compensates based on noise, speed, and other factors). The noise cancellation would do the phase shifting and the "room correction" could be applied to fix the poor accoustic properties of the car (seats, glass, other hard surfaces, etc).

McIntosh does still do car audio as far as I know so it would be cool to see them come up with a solution like this...

[jdandy]

I have some concerns with the long term psychoacoustic effects of active noise distruction systems. Even though frequencies are being canceled using out of phase, same amplitude frequencies to achieve lower noise levels, I wonder about the impact this approach to noise cancellation has on our brain. Even though relative silence has been developed with this out of phase technique, will our brain subconsciously be aware of these opposing frequencies? Will the brain sense a sound pressure level in this artificial silence that it perceives as a higher sound pressure level than actual silence? I wonder if there have been any long term psychoacoustic studies to determine if this type of sound distruction has any mental impact over long periods of time.

[Still-One]

I think you may be over thinking this one Dan. You may be correct, but noise cancellation has been used for several years now, most notably in headphones. I am not saying those of us who have used them are not a bit crazier.

Isn't negative feedback used in audio products a method of noise cancellation.
Jim

[jdandy]

Originally Posted by Stillone

I think you may be over thinking this one Dan. You may be correct, but noise cancellation has been used for several years now, most notably in headphones. I am not saying those of us who have used them are not a bit crazier.

Isn't negative feedback used in audio products an method of noise cancellation.
Jim

Jim.......It is possible that I am making a mountain out of a mole hill, but when one considers an average of 25 hours a week in your vehicle, or 1300 hours annually, that type of long term exposure to out of phase noise distruction may have an unknown impact. The mind is incredibly mysterious, amazing complex, and astronomically sensitive, well in excess of our imaginations, in my opinion. It just makes me wonder if there is a long term impact to active noise cancellation exposure.

Your point about negative feedback is interesting, but this is acheived in the electronic signal path prior to actual sound generation, and is done strictly for the reduction of distortion components in the audio signal. To me, this is not the same as an actual sound that I hear being canceled by another sound that I hear as artificial silence. I am not paranoid about the subject, just expressing some thoughts that have crossed my mind.

[1KW]

Phase cancellation is used in digital hearing aids for years now. The CPU in these aids are capable of making 400,000 cancellations per second and this is in a device which smaller than a dime. Now imagine if you have more room and power to process ? I think that not having the noise cancellation is more fatiguing on long trips than having it. I love my bose noise cancelling headphones when I fly. I sometimes disconnect the wire and just use the noise cancellation, the newest ones are even better.

[80B]

Originally Posted by JJinID

I think it would be interesting to apply this type of noise cancellation in combination with an active Room Perfect / Audessey type solution in an automobile (have active microphones in various places in the car that send data to a processor that compensates based on noise, speed, and other factors). The noise cancellation would do the phase shifting and the "room correction" could be applied to fix the poor accoustic properties of the car (seats, glass, other hard surfaces, etc).

McIntosh does still do car audio as far as I know so it would be cool to see them come up with a solution like this...

In a car, an auddessey type of solution shouldn't be necessary since the physical environment of the car is controlled by the designer, and room correction's purpose is to normalize what is heard for an infinite variety of room and listening position combinations for any given set of gear. In a car, the only thing that is variable is the position of the driver & passengers' ears, and that is within a given space depending on seat position and height. If I'm missing something, I'm all ears....

[Haurock]

Dan,

I don't think there would be any negative brain effects. The brain can only interpret what is picked up by the ear, if the ear doesn't pick it up then its a non-issue. Since hearing is actually different for each of us, I don't think that an application that happens outside of our bodies would have an impact. If what you are saying is true, then deaf people would suffer too, wouldn't they?. The brain is much more adaptive and flexible than we tend to recognize.

[jdandy]

Rock.......My hypotheses is just that, a tentative assumption made in order to draw out and test the logical consequences of active noise destruction. I am not aware of, nor could I locate any information on a long term studiy associated with the effects of this noise control technique. I am not assuming there are, or are not detrimental effects. My curious nature begs for factual answers, not generalizations, assumptions, propaganda, or hearsay.