When you do get one please take a sound meter to it. B cool to see what it reads at idle & cruise.

 

With all that spent on the audio system, did they go through and place additional Dynamat in the car?

 

Yes, that's true to some extent (less isolation, firmer suspensions, more aggressive wheels/tires, etc...). But it also has to be taken in consideration with my earlier comments on different road surfaces today, what happens when you get the natural wear of rubber and sealing-materials over time and mileage, and the effects of colder weather. Even today's firmer-riding new Toyota and Lexus products are probably going to show some increase in road and wind noise, over time, from when they were brand-new....there's almost no way around it.

 

Yes! I did the doors and when deciding on the placement of the sub my final decision to have it in place of the tire tray was not an accident. In addition to placing Hushmat & Ensolite back there along with the sub was to mute the road noise. Also having it be down firing sub and "corner loading" helped the overall sq. This helped achieve some of that but it's still pretty loud back there as the back passenger doors and the area of strut towers were not sound deadened.

 

I didn't think the RX350 was particularly quiet either. But then the Euro cars aren't very quiet at that price point either so I suppose its normal

 

This is crazy. Just went over the concrete causeway leaving the city. The meter avg was 80 DB spiking at 82 DB. Now that I'm back on asphalt its bouncing around at a more "acceptable" 75 DB. I mean I can't make this up. Unreal.

Let's break it down. I have the following back there.
Sound deadener
Ccf Ensolite.
A sub woofer box that's 3/4" wood that measures 6"H x 21" L x 12" W. Next to it is 7" of ccf that hold the wine holder.
A 1-1/2" beauty shelf double padded over mdf.
The regular Lexus cargo flap.
Lexus carpet.
MLV all weather rubber mat.
After all that & it's still loud. There is only so much attributed to tires. Maybe pour sand back there?

 

That's insane. 50k+ and the interior normal operating sonic signature should not have to make you listen to your music at 85 DB.

 

had a 2014 rx350 as a loaner as well. very disappointed in how loud and uncomfortable it was

 

My mom's 2013 makes a lot of engine noise at all rpm's. It's not a quiet ride, but the noise from hers comes from the motor and not tires. She has the stock Michelins by the way. It's been known the latest RX is not quiet. I can't speak for your older model though, but perhaps the RX line has not been in tune with Lexus's quiet mantra for some time. Just guesses. I am convinced the redesigned model will be much quieter. In the meantime, you have a very nice SUV that delievers on many accounts. Try to get used to the noise and focus on the positives. It's a great vehicle.

 

I'm not saying this is definitely the case with your mom's RX, but there are several things that can cause unwanted engine noise. Generally, the colder it is outside, the louder the idle and cold-acceleration until the engine warms up. Are you certain that they are using the correct recommended-grade oil where and when it gets oil-changes?.....improper-viscosity oil will sometimes not provide proper lubrication. Is the underhood insulation pad securely attached and in good condition? And are there any check-engine lights or codes active?...bad sensors can sometimes make an engine run with noise and vibration.

 

Having a drove a 2013 and a 2004, 2007 RX models, I think the 04 -09 generation is pretty quiet. I get surprised in the current one that it's louder than expected, didn't find it much quieter than my 02 Pathfinder I had.

 

Part that is may be the lighter materials Lexus uses today for trim, body panels, interior parts, etc.....

In that area, there is a noticeable difference between today's Lexus products and those of, say, 10-15 years ago. Not that today's Lexus products are loud by any means (actually, they are not).....but some of them seem to lack the tomb-silence of what we saw in the past. Having owned a 1Gen IS myself, I notice it the most in today's 3Gen IS.

 

My 01 GS and 06 GX were very quiet.
But 07 ES, 10 RX450H, and 11 CT were very loud, they are not Lexus at all.
My friend who has an Audi told me that my RX is very loud on the highway.

 

The CT, of course, is loud at least partly from its small wheel wells (not much room for insulation/inner-liners) and small body size also not having much room for added insulation, though Buick proved with the Verano that a small car can be quiet. Also, one sits quite close to the ground in a CT....close to the source of road noise. I said, when I first reviewed a CT, that, although its NuLuxe upholstery was fabulous (better, IMO, than some real leathers), IMHO it was actually more of a Toyota than a Lexus.

 

Good tips above, but not applicable here. Every late-model RX I've driven sounds identical. It's just the way they are. I wouldn't go out on a limb to say they are loud-loud, as in the true definition of the word. Just that it is a shade louder than what I would have expected from Lexus (coming from my older IS) and my mom's former 2005 MDX. I am sure the redo RX will tone down the noise.