A heads up for those with the 07 TL-S with noise cancellation in the audio system.....I was driving to work the other day and reached about 30 mph when all of a sudden, the car started vibrating and shaking as if a wheel was going to fall off. At the same time, the audio system was cutting in and out.....I had to pull the car off the road before it self destructed. As I slowed, the vibration stopped and the audio returned to normal...... Off I went again and again the wild vibrations and audio cutout started.....I pulled over, ready to call Acura for a tow.....then I noticed the rear windows open about an inch. I had opened to let some of the hot air out of the car before I started. I suspected that perhaps the noise from the air rushing by and through the window was somehow being picked up by the audio noise cancellation system and getting amplified by some weird feedback loop. (Note: I am a HS physics teacher, so, I really did think that). Sure enough, I closed the window and the vibrations and audio cutout went away. I repeated with the audio system off and the window cracked open and again, no vibration.

Lesson learned.....do not drive with the audio on and the rear windows cracked open.

 

I do that all the time. Not a problem for me.

 

what is the noise cancellation? makes the cabin quiter or something? more insulation?

 

The Type-S have a microphone located near the rear light. It listens to low frequency sounds that come from road noise. The audio system willl automatically send an inverse wave through the speakers (I think just the rear) to cancell the sound waves originating from road noise. In effect, the cabin is quieter.

People with after-market subs usually will disconnect the wire from the microphone, because the noise-cancellation system can conflict with the low frequencies from after-market subs.

As far as getting weird vibrations from the car...that's really weird. Something else might be wrong with the car.

 

I'm not so sure. Most modern cars are fairly sensitive aerodynmically (not F1 sensitive, but generally). On my RepMobile, if I open a window part way (just a few inches), I will get a great deal of noise and shaking (you can tell it's from wind) at around 45 MPH. At higher or lower speeds, the effect is not as noticable. Close the window - all gone.

Add to the TL-S the Sub working OT to cancel the wind noise and I can imagine what the OP described happening.



I really don't understand how ANC works in a practical sense. Conceptually, no problem - one wave, 180* out of phase with another, cancels both.

But, it seems to me, that by the time microphone hears sound, sends it to be processed and a new out-of-phase sound comes from the speaker, the timing should be off (by just a tad). So that the "cancellation sound" is for noise that occured just a moment before. I'd think that while you get x amount of canclellation, you're also going to get y amount of amplification.

Is there a HS Physics Teacher in the House?

 

Since I've installed an aftermarket system in my Type-S, I don't have to worry about it, however I DO get the same type thing going on in my 07 Odyssey which also has ANC. It's a shame that you can't switch it off, because it really means that you can't roll with the windows down!

 

Had 4 people in my car for lunch the other day. The guys in the back opened the windows, had the stereo on, and I had exactly the same thing happen. It was a DEAFENING rumble. I thought it was buffeting at first, but now reading this thread PLANGP...I realize you're right. ANC did it. And it happened at only about 30 MPH. Now THAT is a bad design.
Glad you posted, I was sure it had everything to do with bad aerodynamics.

 

No problem...

by the way, the problem is repeatable in that I drove yesterday with the same conditions to check out my theory and the sound/pressure waves in the car made my ear drums feel like they were going to pop.

 

Mabey Acura should have made the ANC turn off when the rear windows are open....i mean, when the rear windows are open, it is going to be louder anyhow, thus defeating the point on ANC.

 

I have an 04 TL, so I don't have the ANC in mine. I can get mine to do the same thing as I believe, you are describing, by simply putting the back windows down. You might want to see if you can or get the same results with the radio off.

 

This is not anything unique to the TL or unique to cars with ANC... it happens to many cars. It isn't "bad" areodynamics perse, it's just the way some cars are. Remember areo is designed with window closed, that's where the focus is.

ANC works best for consistant low frequence noise, like road noise from tire. For the most part, road noise if fairly consistant over a stretch of road.