I love my 2020 GLC300 but I’m getting a little tired of road noise: sometimes I can’t even hear my wife telling me how to drive! My Michelin Defenders are silent over smooth surfaces but there aren’t many of those around. Has any body tried any aftermarket noise cancelling strategies?

Sell the car and buy an S-Class?

Seems like a boon :-). The defender is a touring tire and supposedly has some of the lowest noise levels compared to other AS tires. You may need a new set. Tires get noisier as they wear and especially if the wear is abnormal. How much tread depth do you have left? You also may have saw-tooth wear.

The tires are silent on smooth roads (very pleasant and only have 20K miles. I’m complaining about non-smooth surfaces like grooved concrete or tar snakes.

You are barking up the wrong tree. Air suspension or a much larger vehicle (size matters) are the only solutions for you. Or new tires, but you declined that suggestion.

You are attempting to make a silk purse from a sow's ear.

You are attempting to make a silk purse from a sow's ear.[/QUOTE]

There is such a thing as active noise cancelling and some say it is offered as an option on some premium cars. The reverse is offered by several carmakers whose customers want to hear more engine noise out of their stereo speakers; such as the Fiat Abarth.
I was trying to find out if any one has found a way to make noise cancelling work in our cars.

I really would like to avoid discussions about whether your S class is bigger and longer than my C class.

I did see that and my suggestion still stands. The more worn the tires are the noisier they get on the crappy surfaces. These are heavy cars, so they eat tires. AS tires last a bit more, but for comparison I change tires around every 10k miles on my C63. Yes, different, more powerful car, but also lighter and summer performance tires. At 20k I would give those tires a good inspection. Active noise cancelling has to be engineered into he car. That's not something you do after the fact.

There is such a thing as active noise cancelling and some say it is offered as an option on some premium cars. The reverse is offered by several carmakers whose customers want to hear more engine noise out of their stereo speakers; such as the Fiat Abarth.
I was trying to find out if any one has found a way to make noise cancelling work in our cars.

I really would like to avoid discussions about whether your S class is bigger and longer than my C class.[/QUOTE]

I don't drive an S-Class. You are seeking an experience which cannot be delivered by the GLC-Class. Live with it, buy new tires, or buy a new car. That's all you can do.

So I have a saying that goes: “smooth road, therefore smooth car”. I think it’s pretty catchy because I can logically prove my tires are in excellent condition. I know that tires can be somewhat out of balance, or out of round, or scalloped, or with separated tread, but still may occasionally be experienced as being smooth when the stars/tires are in alignment. My tires are always quiet whenever the road surface is visibly smooth. I drive the same roads several times a week and the car is glass-smooth every time when it is on the smooth section - no stars need alignment. I know how tire problems show up and I have none. FWIW, I understand how some cars may not get ideal tire life: I had an RX-8 that wore its tires to the steel belt in less than 11,000 miles. I don’t drive like that anymore and expect to get the full 70k miles on my Defender 2’s.

OK, done with tires. I agree some manufacturers add noise-canceling during the build and I am past that point. I was hoping one of us is nerdy enough to run a noise-cancelling app like a hearing aid app through MBUX to achieve a quieter experience.

Still hoping!

Got AirPods? Or a Bose headset?

I have NOT looked into this

https://www.akm.com/us/en/products/a...-cancellation/

Thanks. I saw that but stopped looking when it became obvious Silentium was not yet ready for retail applications.
Notice their example vehicle was an M-B?

Tires was a good option especially foam filled but OP don't like the idea of new tires....

Still tires though, OP, what tire pressure do you have filled? Tire pressure affects noise levels as well.

32psi all around.

this won't help....

What I PERSONALLY have noticed was my own adaptation to the GLC's noise. My example was trading in my econobox Honda over to a new GLC, and all the noise level drops were astounding: less wind noise, less bump noise, less road noise, quieter cabin, just way way way better. Now, months down the road, I have ACCLIMATIZED to the normal sound of the Benz, and it seems noisy to me. I hear wind, bumps, noise.... my bar has moved. Then after riding in someone else's SUV for a bit, I go back to mine and it is "quiet" again.
It's my perception, I know this, but I can't get around it. It IS much quieter than my other rides, yet, sounds like it is not anymore. But it is.
I even did sound level tests before purchasing from several different vehicles, catalogging the differences, yet my perception bar keeps moving around. Oh well. I do plan to buy THE QUIETEST tires when the next tire trade out time comes around, and may look into more sound deadening in floor and doors etc, but there are limits in physics. And pocket book.

I totally agree. I traded in a Nissan Murano and experienced the abrupt change in overall quality of the GLC. I wasn’t complaining, but a little less wind noise would be nice.