I just got a RWD M3 yesterday. Based on what I’ve read on forums, I expected the interior noise of the 3 to be noticeably loud. Driving 30-40 miles home from delivery I didn’t really notice it being loud, except when I got on the freeway and hit 75+. There was definitely more noise from the tires. Still, it was quieter than our Ford Flex which generates a lot of tire noise.
I’ve also owned a Model S since 2015 (RWD 85) so I decided to compare the sound levels in each. I assume the current S is better/quieter/more refined, so a comparison between a current S and 3 might give a different result.
I used the dB Meter Pro iPhone app by Performance Audio and went on the same drive with each car. I can’t say how accurate this app is a measuring real dB levels, but it’ll do for comparison purposes.
I went for back-to-back drives with each car over the same route. I went for a few miles along a recently paved (and smooth) four-lane arterial that runs parallel to a river with a freeway on the other side; turned onto a mixed-paved and heavily-traveled bridge; then onto the freeway traveling back in the opposite direction for a few miles before exiting and taking a poorly maintained road that transitions to a rough concrete-paved bridge. From there I turned back onto the same smooth arterial I started on and then into our neighborhood and back home.
I measured the dBs at various points and noted the readings for each car. Here is a sample of some of them:
At lower speeds the difference is about 2 to 3 dBs (a difference that is not really noticeable to the average person), but at higher speeds or rougher roads it’s roughly 4 to 6 (noticeable but not annoyingly so).
It is said that 60-65 dBs is equivalent to a conversation in a quiet room at 4 to 8 feet. I was in a coffee/pastry shop this morning and with talking and workers making coffee, the levels were 62-64, for what it's worth. These levels are easy to deal with and present no problem for talking or music in the car. I think the issue is the kind of sound the tires generate relative to how the rest of the car sounds.
For example, as a musician, I’ve played with dudes who haven’t managed to dial in their guitar/amp tone so that, even at lower levels, playing in tune still sounds off and unpleasant. I’ve also been in music venues where the dB level is high, but the mix (of frequencies really) is so good it doesn’t
sound loud. And years ago (before computers), I read an article about automotive frame and suspension design that actually took into account the types of squeaks and noises the frame and body could generate and attempted to tune them to frequencies that would either cancel each other out or were more tolerable to the human ear. Here is an article that touches on that and more:
How Engineers Fight to Wrap Cheapo Cars in Luxurious Silence
So the 3 isn't that loud. The problem seems to me to be the kind of noise the tires generates at higher speeds--it doesn't fit the soundscape of the car as a whole. Maybe Tesla couldn't really address this because, by offering three different wheel sizes and tires, there were too many variables. But what do I know?
