Road Noise?

I have an 03 Miata that I bought with 93K miles on it a few weeks ago. It has a road noise (I think) that starts at about 20 mph. The noise seems to be coming from the front left. It does not matter which gear you are in or if the clutch is in or out, or if the brakes are on or not. I have changed the front left wheel bearing, although the existing bearing looked fine and checked the right bearing. It had already been replaced and it seems ok now. I also jacked the car up and visually inspected the u joints they showed no signs of fretting or looseness. I also turned the rear wheels, looking, listening and feeling for anything that might not be right. All of that felt tight and smooth. I spun each tire and looked at the rotors and they seem to, at least visually, be true and not warped. The noise is is kind of a low roar. You can't really hear it when the top is down. I have noticed that it seemed to change when I aired up the tires form 24 psi to 27 psi. I am thinking that the problem might be the tires. The car has relatively new Falken tires on it.

Any ideas?

what is the sound?

Ditto here. Same noise on my '03. Did all of the same things you did--and checked for dragging brake pads. Dang noise drives me nuts and makes me nervous. I will lurk on this post and see what the pros say about your issue. Thanks for your post!
Paul

Miata has no sound proofing stuff. It is a noisy car! Some tires are louder than the others. Tire pressure also affect the tire noise too. After all this a convertible. If you're bordered by tire noise, this car is not for you. You can drown out the noise by turn up your radio, or better yet get a new header, high-flow CAT and a exhaust. After you've done all these, tire noise is the last thing you will hear. :-)

Have you changed the tires from front to rear to see if the noise follows? Perhaps have a friend drive your car and you drive next to it to see if you can place the sound? Find a Miata pal and swap wheels/tires and see if it goes away.

Did the noise start with the new tires?

The new tires were on the car when I purchased it. They are inexpensive Falken's. When I rotate the tires front to back the sound seems to change but it does not go away. The sound is kind of a low roar, it is not real loud, but it is noticeable. Also, if the top is down I don't hear it. If I am driving in an enclosed parking garage with the windows down I don't hear anything unusual coming from out side the car. As one of the earlier poster mentioned, in effect, I am probably being just too picky. Turning the radio on, even on low, does solve the problem! I am certainly not willing to spend any money to chase it right now!

Sounds like your tires have cupping.