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Discussion Starter · #1 ·
Just started a long road trip and noticed that the engine/exhaust sound in the Hellcat "pulses". Over about a 5 second period, it gets louder and louder, like accelerating, and then falls off quickly. Rinse and repeat over and over. The noise gets to about the same volume every time before falling off.

This seems to happen with or without gas and on or off cruise control and up or down hill. That is, I don't seem to be able to affect it. The only thing I noticed is that if we are going slower (e.g., 50mph) the period is like 7 seconds whereas going 70mph the period is more like 5 sec. One thing that does stop it is going over 85mph :) Works as we pass through Montana but less helpful elsewhere.

Having just learned about the Active Noise Cancellation feature (cool) I wonder if it could be that we have the back of the Durango (everything behind the second row) absolutely (like really) stuffed with luggage, blankets, boxes, ... My theory is that the stuff is blocking some of the microphones causing it to get louder than normal in the car before tripping the cancellation and the cancellation effect drops over time (so the car gets incrementally louder). Either that or we are blocking some of the noise generating speakers (ones on the D pillar perhaps).

Obviously taking the stuff out would answer the question but that's super hard to do right now and we still have several days to go. Anyone got any experience with this sort of on again/off again noise? Could it be something completely different? It all sounded normal before this trip.
 

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Why would you want to cancel the song of a Hellcat? :unsure:

Can you turn that off?
 

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I believe the ANC microphones are in the roof so yes, having a full cargo area might impact some of what they pick up, but one would hope the algorithm would factor that in and you might be seeing the lag as the system compensates at different speeds. Another thing you can try is put your Hellcat into Tow mode. That drive mode is supposed to have the most aggressive noise cancellation setting of all the modes. See if that changes anything.
 

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Discussion Starter · #4 ·
Why would you want to cancel the song of a Hellcat? :unsure:

Can you turn that off?
Uhhh, 6000 miles is a long time for that one note song.

I don't think you can turn it off but it does seem that you can defeat it. Apparently by muffling the microphones.
 

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I have not filled the back of mine to the rafters...and I have not noticed any noise cancellation or artificial manipulation...so must work well for me..🙉
 

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Just started a long road trip and noticed that the engine/exhaust sound in the Hellcat "pulses". Over about a 5 second period, it gets louder and louder, like accelerating, and then falls off quickly. Rinse and repeat over and over. The noise gets to about the same volume every time before falling off.

This seems to happen with or without gas and on or off cruise control and up or down hill. That is, I don't seem to be able to affect it. The only thing I noticed is that if we are going slower (e.g., 50mph) the period is like 7 seconds whereas going 70mph the period is more like 5 sec. One thing that does stop it is going over 85mph :) Works as we pass through Montana but less helpful elsewhere.

Having just learned about the Active Noise Cancellation feature (cool) I wonder if it could be that we have the back of the Durango (everything behind the second row) absolutely (like really) stuffed with luggage, blankets, boxes, ... My theory is that the stuff is blocking some of the microphones causing it to get louder than normal in the car before tripping the cancellation and the cancellation effect drops over time (so the car gets incrementally louder). Either that or we are blocking some of the noise generating speakers (ones on the D pillar perhaps).

Obviously taking the stuff out would answer the question but that's super hard to do right now and we still have several days to go. Anyone got any experience with this sort of on again/off again noise? Could it be something completely different? It all sounded normal before this trip.
Hi Ddhc24,
Please be sure to keep us posted as you continue to monitor this. If you find yourself having to work with your dealer, we're more than happy to get you connected with case specialists who can work alongside your dealers to explore all potential solutions. Feel free to follow up with us via private message if this would be of interest.

Rob
Dodge Cares
 

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Just started a long road trip and noticed that the engine/exhaust sound in the Hellcat "pulses". Over about a 5 second period, it gets louder and louder, like accelerating, and then falls off quickly. Rinse and repeat over and over. The noise gets to about the same volume every time before falling off.

This seems to happen with or without gas and on or off cruise control and up or down hill. That is, I don't seem to be able to affect it. The only thing I noticed is that if we are going slower (e.g., 50mph) the period is like 7 seconds whereas going 70mph the period is more like 5 sec. One thing that does stop it is going over 85mph :) Works as we pass through Montana but less helpful elsewhere.

Having just learned about the Active Noise Cancellation feature (cool) I wonder if it could be that we have the back of the Durango (everything behind the second row) absolutely (like really) stuffed with luggage, blankets, boxes, ... My theory is that the stuff is blocking some of the microphones causing it to get louder than normal in the car before tripping the cancellation and the cancellation effect drops over time (so the car gets incrementally louder). Either that or we are blocking some of the noise generating speakers (ones on the D pillar perhaps).

Obviously taking the stuff out would answer the question but that's super hard to do right now and we still have several days to go. Anyone got any experience with this sort of on again/off again noise? Could it be something completely different? It all sounded normal before this trip.
Hi Ddhc24,
Please be sure to keep us posted as you continue to monitor this. If you find yourself having to work with your dealer, we're more than happy to get you connected with case specialists who can work alongside your dealers to explore all potential solutions. Feel free to follow up with us via private message if this would be of interest.

Rob
Dodge Cares
 

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Discussion Starter · #8 ·
Sure. Thanks. Quick update. Tow mode is definitely better. Slightly louder than the quietest but no rhythmic pulsing. Mileage didn't seem much different than eco mode.

We did clear out some of the blockage around the rearmost mic. That improved things a bit at high speeds but not a solution.

We'll be unloading a bunch of stuff tomorrow and that should let us clear the speakers and mic in the rear. Will report more then.
 

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Discussion Starter · #9 ·
Following up on this. After dumping most of the stuff in the back of the vehicle (from the middle row back), the rhythmic thrumming is gone. That and the fact that putting it in Tow mode helped a lot strongly suggests it is either the Active Noise Cancellation failing to work well or over-compensating. With one of the mics (rearmost) and both D pillar speakers (and perhaps others) blocked either the ANC was unable to detect, and thus cancel, the noise or it detected the noise and kept boosting the cancellation until it decided enough was enough.

In any event, for folks finding this later, look to clear both the headliner mics and the speakers to ensure the ANC system can work as designed.
 

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So can you notice the Active Noise Cancellation when driving normally? I question whether it actually does anything on my Tow N Go. I have never been able to notice whether its functioning or not. Is there any way to test it???
 

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So can you notice the Active Noise Cancellation when driving normally? I question whether it actually does anything on my Tow N Go. I have never been able to notice whether its functioning or not. Is there any way to test it???
I'm interested to know this as well.
 

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So can you notice the Active Noise Cancellation when driving normally? I question whether it actually does anything on my Tow N Go. I have never been able to notice whether its functioning or not. Is there any way to test it???
i've been wanting to test an on/off with this in my ram forever! i wonder if the only way would be to pull the fuse for the radio....but who knows what else that would eff up (since most non-radio controls are part of that system)
 

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Discussion Starter · #13 ·
I noticed a marked difference between Tow mode and all other modes when the back was completely stuffed blocking the mic and speakers. (Tow did a better and more consistent job). Yesterday i tried just switching between driving modes and did not notice any difference in sound levels but I haven't done careful testing.

There are several threads around on how to disable ANC. Not sure if any of them work but may be worth a read if you want to go that route. You could try just covering the mics and speakers with some sense foam or some such to see if that does anything.
 
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