liveperilous

Is it me or does it make absolutely no difference wheather it is on or off? I can't tell the difference at all? Also does the car sound a little noisy, kind of like it is not insulated well.

jftjr

It makes no difference because you can't turn it off.

The ANC cannot be turned off by the user.

liveperilous

Humm, I thought it can be turned off using the controls. If you are in the audio mode, you can go in and choose to turn it off, it is right above the centerpoint option.

jftjr

Search the forums.

What you're turning off, AudioPilot, isn't the ANC. It's the active equalization of the music that increases loudness and changes EQ based on things like vehicle speed and whether the windows are open.

The ANC is a separate but related system, and cannot be turned off.

CGTSX2004

iTrader: (1)

True, yet false. While the system cannot be turned off, you can temporarily disable it by placing a hand over the mic opening to prevent the input to the system which prevents output.

The mic is located in the overhead console between the front seats.

jftjr

That's not turning it off. That's covering up the microphone. Big difference.

Treblig

There's also one in the rear just ahead of the rear reading lights.

sambiam

Is there any way to test it to see if it is effective???

jftjr

Sure. Cover the holes with your fingers.

Or, sit at idle in a quiet area with the AC off. If you gently tap on the headliner around the microphone (really gently...) you can hear the subwoofer and speakers thumping back at you.

It's subtle.... but you can hear it. Gentle rhythmic tapping works best. IF you hear that, it's working.

bobwied

You're absolutely right, there isn't any insulation in the doors or trunk lid. I've had all my door panels removed, the whole interior gutted, and the trunk panels removed to add insulation. The car is now much quieter, although I can't wait to get a new set of tires (which I think are the main contributors to the problem) to see how quiet it can actually be. Nevertheless, I was shocked to see how poorly the RL was soundproofed. I think they counted on the noise cancellation to do the job. They should have added insulation from the start, NC is not enough by itself.

stingerbtry

That's just it, it's not poorly done. They made it that way to be lighter since the active noise cancelling takes care of most of the sound that heavy insulation normally would. You make it sound like they just cheaped out and hoped for the best thinking oh well, hopefully the noise cancellation works. I'm sure much more went into it then that. I think the car is pretty damn quiet considering and once I get new tires I'm sure it will be a whole lot better. I think they were most concerned with weight savings since the car already weighs ~5000 pounds. I'm guessing that by simply tearing the car apart to add the extra noise dampening you're going to scare up a few extra rattles and squeaks yourself.

jftjr

You did all that BEFORE changing the tires?

No way that tearing the interior apart isn't going to cause you more rattles down the line, especially in a car that's rattle-prone to start with.

liveperilous

HOw much did all that cost you to tear down the car and put insulation in it? Do you have rattles now?

Rob L

Yep no doubt the ANC is a substitute for actual sound deadening materials. It works ok but IMO the car isn't as quiet as some make it out to be. At idle the RL is damn quiet but under way it isn't as quiet as the new GS, the new IS and isn't close to the LS430.

I realize tire noise of the crappy OEMs is a main culprit but that isn't just the noise.

liveperilous

yeah my concern was comparing the car to the E500 or even the 545i. I am surprised that the noise level on the car is as loud as it is. Heck a Honda Pilot sounds quiter! You know what is another 75lbs for the car? It already weighs as much as it does, Acura should of put insulation on the car.

eaRL

But they did put sound insulation in the car. Because of the properties of sound, when the ANC produces the out of phase signal the original sound wave (the wave that would have introduced additional sound into the cabin) does not exist anymore. That said, I agree the car does become louder than I would expect at highway speeds. The TL has sound insulation in the wheel wells which I think is a good idea. That feature could be beneficial on the RL as well or something along those lines.

Example: Sit in your car with with all windows rolled up. Turn everything off except the engine. Place only the fingertips of your left hand in the middle of the driver's side window. Place the index finger of your right hand over the ANC microphone making sure that you are covering the microphone as best you can. Once you do that you will hear a low rumble fade in and you will "feel" the driver's side window vibrate slightly. That slight vibration represents sound that is present inside the cabin. Remove your finger from the ANC microphone and the vibration on the window and the noise itself will go away. That vibration was introduced when the "sound insulation", in this case ANC, was for the most part removed.

bobwied

I guess we'll see down the road whether rattles are a problem or not. So far the car is as rattle free after the work was done than before. I suppose I'm more concerned about how the vehicle performs now than what might happen at some later time. If it develops some rattles I'll deal with them at that point. You may get rattles without ever removing any of your interior.

That said, the sound deadening (www.cascadeaudio.com) that I used (including the installation) cost less than a set of new tires. The car is quiter already and will be more so when the OEM's are replaced. But now I don't feel quite as compelled to run out and replace a set of tires that have only 5k on them.

bobwied

I can't yet say how much quiter the car will be with new tires, but from the factory it is not as quiet as I think a car of this caliber should be. The amount of noise in the cabin varies greatly with the composition and make-up of the road. To be fair, on newly paved roads the noise wasn't too bad, but otherwise, at 60 mph it was just too loud for my tastes.

As for the weight, I've logged every tank-full of gas I've put into this car. Adding the insulation did not affect my mileage at all, nor did it affect the performance. As an added benefit, the doors now close with a reassuring thud, and I can listen to the same CD's as before the work was done but with the volume levels 2-3 clicks down. IMO it was worth the upgrade.

Ken1997TL

New tires make all the difference.. your best bet is to use some sort of spray in the wheel wells that will absorb the "roar". Due to double-wishbone suspension systems eating up a lot of room, you have these larger than usual wheel wells that make a lot of racket.

Nocturnal

I wonder how quiet this engine is compared to others on the market. I sold my S4 (2.7TT) the other day and when I drove it the last few days it again struck me how quiet and smooth that engine was at 55K miles compared to my RL at 5K. Maybe it's simply that the S4 had better insulation or perhaps the engine is quieter? Certainly 3.5L is about as big as you should make a V6 before the engine becomes rumbly.

General quietness of the car is fine though. Some roads cause too much noise for the HFL to be effective but I shouldn't yap on the phone anyway.

bfeng

Try sitting in the back seat and listening to any amount of deep bass droning from the engine.

bfeng

bfeng

Then put something removable (bit of clay, your hand) over both the front and rear microphones (make sure AudioPilot is turned off). You should hear a difference.

BTW, the amount of sound isulation a carmaker uses is a very delicate tradeoff between cost, weight, and space. Every pound of extra weight reduces the effectiveness of the engine, might hurt fuel economy, and is probably not good for handling. Acura does an amazing job with a V6, when compared to everyone else's V8.

Bfeng

jftjr

I'm curious, however, about weight loading v. alternator loading. I mean, the really low-freq stuff they can tune out with chassis stiffness and suspension... it's the mid-level rumble (say, 30-100 hz) that the ANC probably deals with. Certainly, the ANC has to crank out an appreciable amount of wattage through the audio system, at all times, to surpress that noise. And LF requires more amplifier power to reproduce than higher frequencies... so if the amplifier is drawing, say, 60 watts at 12 volts nominal, then that's 5 amps of current drawn at all times -- which is a pretty good alternator load. How does that compare to, say, 20 lbs of sound insulation?

bfeng

You've made a bunch of assumptions.

Chassis Stiffness: do you mean static or dynamic? How does it correlate to the chassis drivepoint for the transmission of engine "noise" to the interior? A stiff chassis could also be a less lossy chassis (e.g. more efficient at transfering noise energy and resonating in the audio band). A more flexible chassis moves the resonance down to perhaps a subaudible frequency range (which you then feel thru the seat of your pants).

One thing you mention is important, lower frequency means more energy.
As far as the canceling energy required ... first you have to know the energy of the sound you want to cancel. Then you have to decide how much cancellation is enough to make the sound no longer annoying. Finally, you have to know how efficient your audio system is.

If a hypothetical audio system has a 100watt woofer (that's could be a pretty darn loud woofer), and the loudest engine noise you wanted to completely eliminate is 10dB less loud than the loudest the subwoofer can play, then you need 10dB less power for cancellation than for music. What's 10dB less power than 100watts?

Bfeng

jftjr

Well, that's what I'm asking you... and if you can't tell us, you can't tell us, but I imagine a lot of details are available in the patent....

Anyway, yes, I'm assuming that the real LF frequencies are dealt with in more conventional ways such as chassis tuning. I can't imagine that the Bose system deals with the ~15hz stuff, because it would require too much energy, and too big of a woofer.

You mentioned harmonics, however -- and harmonics have less energy than their fundamentals, so they require less energy to dampen.

Assuming that the amplifier has a linear power curve (it doesn't... but bear with me, I only had 1 year of engineering school...) 10db less power than 100W should be 10W, since the db scale is powers of 10, right?

The simple question, though is... about how much current is the ANC drawing from the electrical system to dampen the noise? That's what I'm really curious about -- what's it take to run the system all the time, and how much amplifer power is being dumped around my head at all times.

bfeng

Engines are funny things. The harmonics can and are typically larger than the fundamental (true for a few musical instruments as well). A V6 typically has more 3rd order than any other harmonic. Different vehicle designs can alter this some, but it's not a bad generalization. I4's are dominated by the 2nd harmonic. Why? An I4, 2-stroke has 2 firing per rotation. Hence there are 2 impulses per rev (the other 2 cylinders will be on their intake strokes), and 2nd harmonic dominates.

Power: Lets say, just hypothetically, your RL system can hit 115dB SPL at 40Hz.
There aren't may engines that loud ... maybe the one in my open exhaust race car is louder. Check some test reports. How loud is an RL at wide open throttle. Maybe 80 odd dB SPL. So, the engine, in this jypothetical case is 35dB quieter than the max bass of the audio system. If the audio system had 100watts on a woofer, how many watts do you need to generate that cancellation signal. Not all that much. Caveat. dBSPL in a car is normall 1 or B weighted. So, the linear dB SPL level is higher, but not 115dB. So, yes it takes some power, but not as much as you think.


bfeng