To make a very long story short, I have been on an insane crusade over the last decade to measure vehicle cabin noise in the expensive / super expensive categories. I take it to an extreme level but I won't go into detail here.

tl;dr Car & Driver also takes this extremely seriously. Their full methodology can be found in the * below (updated for this year). They've also been testing it in the same location (They have two facilities) over the last decade or two.

Anyway, per https://www.caranddriver.com/news/a3...highway-range/

"In our testing, the BMW iX recorded an average of 66 dBA with the accelerator pressed to the floor, and 63 dBA when driving along at a steady 70 mph. This puts it among the quietest cars we've ever tested. Only four cars have been quieter at highway cruising speeds—a 2019 Bentley Bentayga V-8 (61 dBA), a 2019 Rolls-Royce Cullinan (62 dBA), a 2020 Audi S8 (62 dBA), and a 2019 Jaguar I-Pace (62 dBA). The iX was significantly quieter than this quartet at wide-open throttle, even beating the fully electric I-Pace, which measured 71 dBA under heavy acceleration. And the iX is far more serene than the quietest Tesla we've ever tested, a 2021 Model S Long Range Plus, which came in at 66 dBA.

BMW's EV SUV outdoes some seriously luxurious vehicles at keeping it silent on the highway. The iX measured one decibel quieter than a 2020 BMW 745e plug-in hybrid, a 2021 Mercedes-Benz S580 4Matic, and a 2021 Cadillac Escalade 600. The iX also easily betters these three gas-powered land yachts when it comes to lack of noise during maximum acceleration."

So iX is 66dba under WOT, 63dba at 70mph
S8 (with 23" rims) was 62dBA at 70mph
S class (W223) was 64dBA

So an S8 is quieter than a W223 which is shocking because previous generations of testing with C&D (D4 model) had the A8 quieter than the S8 by "a fair bit".

Why did I post this?

-I'm genuinely shocked. The W222 was only a fraction louder than the A8 and that had RFTs in MY testing at 1xx kph and I have no doubt the W222 would be even quieter with non RFTs. The W223 is generally reviewed to be quieter than the W222, and C&D found otherwise. Do most people care? Of course not. Did I find it interesting? Yes.

--Now before the haters come after me - I am simply sharing data from C&D. I am in the market for a W223. I have absolutely *0 interest* in vehicle bashing or whatever. I'm too old mentally for that sort of behaviour!




*https://www.caranddriver.com/feature...r-noise-sones/

 

Lexus LS 500 reference per: https://www.caranddriver.com/reviews...i-rs-q8-drive/

" Another typical drawback of performance cars is the rolling noise generated by rubber this wide and grippy, but this Audi sails along at 70 mph with just a 67-decibel whisper of background noise, one more than a Lexus LS sedan."

​​​​​​​Lexus LS500 - 66dba

--

I'm not shocked. The LS500's noise levels stood out to me immediately, especially on the highway

 

Because this is all volunteer work on my part, Im' not going to cite all of my work but it's all public info from C&D. Just dumping stuff

Range Rover on 23s: 66dba
Cayenne Coupe/Regular: 65/66
RSQ8: 67 per above dba
Rolls Royce Ghost: 62dba
Rolls Royce Spectre: 63dba
RR Phantom (older model): 64dba

 

Low to high sorted all at 70mph

Rolls Royce Cullinan- 62dBA
Audi S8 (23s) -62
Jaguar I-Pace - 62
Rolls Royce Spectre: 63
Mercedes S class - 64
Rolls Royce Phantom (old model) 64
Cayenne Coupe/Regular: 65/66
Range Rover - 66
Lexus LS500 - 66

 

Well after four years on the road and onstage with the dead my hearing even with my hearing aids is not great, top of that old age. To give you an idea I think the stereo in the 4C sounds good. I see that you are here as well as the Range Rover forum OP. With the exception of my Range Rover and my G70 760 all of my cars are loud so while I’m not surprised that EV’s would not be as loud as gas powered cars, my friends that own them often complain about wind and tire noise.

 

Curious how the noise is with the Maybach W223.

 

I wouldn't overthink small variables, and also note that sound pressure does not necessarily translate into perceived noise. Temperature, pressure, weather, wind of varying days all change results and much of that can't be controlled for. I am also nuts about a quiet car and have driven everything of note and own my own sound meter I use to test cars, all of these cars are very similar in terms of cabin noise. Having had a 222 and a 223, my 223 is definitely quieter than my 222. The 222 isolated from road noise very well, but didn't isolate from wind or outside noise as well. My 223 isolates from outside ambient noise better. My LS460s actually isolated from wind and outside noise better than my 222, but not road noise. My 223 isolates from wind and outside noise as well as the LS460s while isolating from road noise better. My LS460L and my S560 and my S580 all measure about the same dB rating, 59-60 at 75 MPH, yet there are differences in how they "feel".

Also, the S Classes have active noise cancellation while those LSs didn't, that doesn't come across in a sound pressure reading but does in your perception.

With the exception of the LS500, A8, W223, G70 7, G90 all very quiet and similar.

 

OP, you bring an excellent point about the iX as well as how these cars stack in terms of noise level. It is extremely surprising how only 1 dBA difference translate into noise level that we can easily notice when testing these cars. A Rolls Royce (although I’ve been only in 2 modern models recently) is noticeably more quite that these cars on this list although the difference is only 1-3 dBA. Same for the iX (I was shocked, and I think BMW is adding Rolls Royce secret sauce into some of their EV lineup, particularly in the sedan and the rubber and thick beefed up double weatherstrip around the doors). Nobody knows how to do that better than Rolls. Where the iX did not do very well was against wind because it is an SUV, but door seals did well. I bet if they replaced the tires with NRF that would reduce the dBA even further. EVs come with the most noisy RF tires every because of the low rolling resistance that they emphasize (and they are still more quiet perhaps because of how batteries insulate the most noise part of the car, the bottom side, while rest of the car is well sealed against wind). Replacing those RF in an EV with NRF improves the road noise much more than the same impact of replacig RF with NRF in a typical gas vehicle, and widen the gap even further. It is outstanding to see Audi up there; am excited to test drive a new S8 honestly.

 

The human brain is a very interesting thing. The A8 is a 7 year old car and no doubt is on 0 people's shopping lists here so hopefully I can say this without people coming after me. That vehicle predated the Ghost and then the Phantom and is truly an underappreciated car (thankfully). My thoughts were echoed when Savage Geese reviewed it.

The A8 is disorientatingly quiet and the massage seats truly work - no other Audi has the same massage seats (I've tried them all). I'm relatively skinny, and the W222's massage seats are like a 1/10 and the A8's are ~10/10. That's how big of a difference it is. The quietness though almost made me fall asleep a few times driving home from work. It is so...comforting to the point where I would get sleepy driving it. It's a work of insane engineering and that's why I'm keeping it forever and I genuinely hope people don't know it and don't buy it. It's much more rare in Canada than even a Ghost.

Why weird? Well one day after putting a pet down I drove home in the A8 and all I could hear was wind noise. Funny how that works out, huh?

In all seriousness, these objective testing results serve as a great baseline to what is otherwise subjective opinions of cars. You're right, getting rid of RFTs and such would help, as would going to smaller rims. C&D did testing on an A8 vs an S8 in the previous D4 A8 model and they were 2-3db apart so that 2020 S8 at 62DB in my OP is probably a 60db or whatever for an A8. It's a big difference.

I think we're at a point though where carmakers have all but given up on this front. In the 66DB range per C&D are these cars: Range Rover, EQE, EQS, LX600, LS500, ES350, Grand Wagoneer, Escalade, Navigator Black Label, GX500, Defender & G class MErcedes.

All 66-68db. Yawn - I'm bored.

On the 62db side, they all do the same thing - triple seals and acoustic glass. Someone wake me when Rolls Royce does 4x seals and triple laminated glass (PLEASE!). I really want OEMs to push into the mid 50s for DB.

I sold the Ghost but kept the A8. I could buy 3 A8s for a Ghost and I kept the A8. It's that quiet, but it has minimal presence which I like most days. It is after a long and stretched Beetle And when I want to be gaudy and do the whole "LOOK AT ME", I just take out the other two cars, haha.

Appendix:

A different reviewer, but believable.

Ghost at 58dba at 70mph, and Phantom (new model) at 60db.

https://www.autocar.co.uk/car-review/rolls-royce/ghost

Seems reasonable to me (given Cullinan was 62 per C&D). So we've hit the floor of 58db. Yawn. We can send men to the moon...surely...we can do better here.

 

It is also very interesting to see that even within the same testing agency / car reviewers, data is a bit all over the place.

Autocar.co.uk does some serious proper noise testing and they use the same road, etc.

W223:

Cabin noise - idle
38dBA
Cabin noise - 30mph
54dBA
Cabin noise - 50mph
59dBA
Cabin noise - 70mph
62dBA
Cabin noise - max revs in 4th gear
74dBA

Range Rover:
Cabin noise - idle
37dBA
Cabin noise - 30mph
52dBA
Cabin noise - 50mph
55dBA
Cabin noise - 70mph
61dBA
Cabin noise - max revs in 4th gear
70dBA (fifth gear)

Per: https://www.autocar.co.uk/car-review...lass-2020-2026
https://www.autocar.co.uk/car-review...er/range-rover

Misc: I made a mistake in my OP. The S8 had *21s*. Most A8s have 19s or 20s.