Road noise (on some pavements more than others) - targeting fix?

[Kevy kev kev]

HI,

Road noise is making it hard to hear in my normally quiet 2017 prius 4.  When I think of where it is coming from... I think

1) wheel wells around the tires
2) Door panels, which are thin

3) Seals around door may or may not be getting old (I see black marks where they sit against the metal of the chassis.

4) Floor panels?

5) Roof.

I have been searching for articles on any testing that was done and the internet is resisting or there is not much on it that is not trying to hard sell you a specific product from non trustworthy sources.   My last Prius I replaced that tires with some quieter ones... but 15/20K miles (yeah I am from the US) down the road the tire noise was back to loud.

on smooth asphalt the car is so quiet... it can get loud as the speed gets over 60mph as the wind noise picks up a bit.   Rough pavement at 70mph is just too loud.  The stereo is nice, but I am unable to heard the subtleties of the music and instruments get drowned out.  Conversation is hard with people who do not project their voices.

I would like to quiet it down and know the areas that will have the most effect to start with.   Money and resources are at a minimum... so the best bang for a buck is a must.

[Roy124]

Kev, you answered your own question. Different tyres and smooth roads. 

You could change wheels to smaller metal and larger rubber.  Drive at a slower speed, reduce noise, save fuel. 

[Kevy kev kev]

I appreciate you, but I am looking to hear about dampening or deadening mods.  Tires are expensive and the properties only last 15-20K miles.  I do not have low profile tires.

[Hybrid21]

My RAV4 is similar with the Toyo tyres.

But I'm too mean to change them to a quieter tyre unless they are worn enough 😀

[TonyHSD]

Which part of the country are you in? If on the colder northern side you can buy Michelin cross climate 2 all season all weather tyres that has V shaped tread pattern and these usually dampen the road noise caused by rough road surface. No summer tyre or any other tyre can dampen so well as V shaped winter it all season ones. Here in uk we have mostly these rough asphalt and when I am on my winter set the car is quieter as German premium brands, summer tyres even best in business are not as quiet. For mods there are many posts but not sure if anyone actually has achieved any excellent results that worth the money and effort. Simple tricks, use quieter tyres, use carpet matts, add extra carpet in the boot. Treat all door seals with silicon paste or spray once a year. Well that’s all. 

[Trewithy]

Over inflated tires can add to the noise levels.

[Roy124]

Combining Tony's suggestion and Trewithy's comment, does the recommended pressure change from winter/summer tyres.  How much underpressure would be acceptable. 

Clearly if you run 'soft' you would need to Che l pressures more frequently.