sebljo

Has anyone found any info on the net about how this system works?

talon90

There are microphones mounted in the cabin (door panels) that "listen" to the sounds present from road noise, engine noise, exhaust sound and other ambient noises and the system generates "white noise" to cancel the sound waves.

NSC5

Paul, Doesn't Bose actually produce a phase inverted waveform to cancel the targeted noise? This is what they do with their other active noise cancellation products.

Mike Mercury

close.

The audio system generates the same sound being heard in the car - but 180 dgrees out of phase. The output of the radio negates the noises.

Z0Sick6

is this on all the BOSE or only the upgraded 2LT and 3LT?

george vee

I wonder how this will help with the rear tire noise the coupe generates?
I will know soon enough since my C7 went to 4D00 today.

-CM-

So the system is listening all the time. I wonder if the NSA will tap into C7 audio systems. Oh, wait, that was a different thread.

Mike Mercury

AORoads

I'm not sure how to read the "box" description but it seems to me it's listening only to the engine noise in the cabin? That may be wrong; someone correct me plz because otherwise it's not listening to all the other ambient noise (such as the tire noise).

2014greenstingray

According to the Bose website, its AudioPilot technology is noise COMPENSATION, not noise CANCELATION. It selectively and continually adjusts the waveform of the program music to compensate for the background noise, meaning that it increases the volume of some parts, generally the softer sections, while leaving other parts unaffected. This is better than an overall volume increase with speed (standard on GM for a long time) or general background noise, but it does not appear to generate a noise-cancelling waveform similar to Bose headphones. Therefore the system will not reduce cabin noise in general, at least as I understand their explanation.

stevebz06

Ford, and some others, are piping engine noise into the cabin. Chevrolet is trying to make a limo out of the Corvette. I see where a minvan now has a built in vaccuum. Maybe we should be trying to get one of those in later year models.

robvuk

I have heard it referred to as a noise "canceling" system, not noise compensation. I don't really know for sure either way. But if it's noise compensating, that would be fairly disappointing in theory and I would definitely have to hear it to experience it's value. If it's noise canceling, I'm going to use an educated guess that its effectiveness will be limited to mostly low frequency noise (below 200-300hz). Digital technology is quite remarkable and its possible I could be surprised but this is jmho at this point.

Oh and its funny that no one has even mentioned it in any of the reviews we've read so far.

sebljo

So, does the entertainment system [radio] have to be "on" for it to work or is it something that is "always on"?

NSC5

The early Bose press release that goes into some detail makes it appear the C7 only has the audio pilot which is an "improved" version of what Bose has used for years. The Bose system in my 2006 GMC Sierra simply increases/decreases the total volume level based upon ambient noise level and it has three sensitivity settings. Jump forward to 2014 and the audio gain is changed only in specific frequency bands to overcome specific noise sources. So to compensate for tire noise low level audio signals from the entertainment unit would be further amplified as necessary to overcome noise in this particular frequency band. Audio signals outside of that band and signals within that band that are sufficiently loud would not be modified.

I assume the amount of gain change is subtle or this will create some really odd modifications to the overall sound of the original program material. I am not a "Bose basher" and have two different home systems with 901 series speakers along with Bose in my other GM vehicles but I do have reservations about this system. I much prefer my CTS sound system with it set to normal instead of the processed "Centerpoint" sound from Bose and I don't think I am going to like Audio Pilot either. From the Bose description it sounds like the British expression, "too clever by half". If some of you have experienced the DBX range expansion devices which can undo some of the dynamic range compression applied during the audio production process it has the potential to sound very good but overdone creates very noticeable effects along with some strange artifacts depending upon source material. Audio Pilot certainly sounds like it has the same potential and could be responsible for at least that one reviewer who did not like the muddy sound.

Here is the Bose webpage explanation, click on explore for further detail: http://worldwide.bose.com/axa/en_au/...logy/page.html

robvuk

Thanks NSC5. Well that clarifies a lot for me. It didn't seem right to me from the very beginning that microphones built into the door panels a foot and a half away from your head could be effective as noise "canceling" devices.

SO let's make sure that this system is referred to in the future as "noise compensating audio" NOT "a noise canceling" system. This would explain the lack of comments in the reviews as well. Its effectiveness can then be determined, used and adjusted by the user.

DEciiBel

Elsewhere on the forum a number of audio aficionados spoke of retro-fitting. If this form of noise compensating is employed by GM, it will only urge them on.
Why?
I am so glad you asked.
To meet the demands of noise induced increased amplification, the amplifiers will need to be robust (costly) or there can be the consequence of increased distortion (which Bose has a history of ignoring), when they begin to clip the audio form.
The deliberate introduction of distortion in the synchrony of the volume, the departure from a flat response across the entire bandwidth of a signal, may be appalling. Like added swells on a drag track.
Noises that you may hate, tire roar f'rinstance, may balloon instead of being swallowed. Your conscious self may be able to ignore this but nothing is ever completely ignored. They call it listening fatigue.
Bose has been huge in psycho-acoustics and these groanings could be misplaced. That's OK though because according to them, you could just turn up the yeahing and simply overwhelm my naying.
Identifying what is noise and eliminating causes, followed by sound isolation and insulation is where you start to control unwanted sound. Noise suppression can be done actively and far more efficiently after the first actions.
Ramping up the volume is a freaking kludge no matter how specifically you apply it. The current system's sledge hammer approach (Make it all louder.) is an irritation to me.
If they used microphones and speakers near the ears, noise cancelling could be optimized and would make a nice add-on. When you want to be deafened (or listen to the passenger) turn it off. Selecting the frequencies of the out of phase cancelling would be cool. To direct the effect to the cabin's speakers or seat speakers when you do have someone aboard would be cool.
If you could mute them for a bonus, wow!
Imagine a mini-van application. The kids are screaming? What kids?
I wonder if you could still shift by ear? Although that's a vanishing concern with the coming of auto-everything and electrical motors.
Sigh.
The new world will have no rough edges.

DEciiBel

You have to remember that you are dealing with sound. Expansion and compression of the air at timed intervals say 30 hertz (or Cycles per Second) means that a full wave (pulse) takes a thirtieth of a second.
Since sound travels at about 1000 feet per second, this 30 Hz sound takes 30+ feet to be fully deployed.
A couple of feet are not an impediment for controlling this.
When you get to the shorter frequencies, moving the ears at all can make it impossible to overcome those sounds.
That's the reason those headphones are so effective at buffering noise.
You also get involved with the how large the compensating diaphragms and enclosures need be for those very low pitches. Low notes cost more money, ridding yourself of them will cost at least as much.
There are rea$on$ why this stuff isn't common.

Michael A

I saw a number of news releases saying the car has noise cancellation. The term noise cancellation to me does not imply a form of speed compensated EQ.

Also Motor Trend said the 2LT/3LT Bose system with the sub box better cancelled the AFM drone than the 1LT system without the sub box.

I definitely would like to get more info on this.

Michael

robvuk

Kirk Benion himself used the term "noise canceling". And I still stand by my conviction that it would be extremely difficult at all but the lowest frequencies and the distance of the mics from the ears. We definitely need more clarification on this subject.

Glen e

I believe it works just like Honda or Bose's noise cancelling headphones...

http://www.honda.co.nz/technology/driving/anc/

Note to those that are going to mount their own subs...these systems do mess with them....