What would cause infrequent buzzing sound when turning or driving straight.

What is your question?

Uncertain when the high-pitched buzzing sound started, it's my wife's car, but it seems she started to mention the noise some time after we bought new tires. It's difficult to explain the noise; I do have a recording of it but there's no option to upload the audio file on this web site. It appears the noise is coming from the front of the car on the driver's side. It is not grinding, scratching, growling, thumping, humming or any of the usual sounds I have encountered before. I have checked the structs and the brake pads for excessive wear, they're both okay. I have been under the car and have not found anything to be loose or missing. The timing belt and water pump were changed about four years ago. The car is basically for work commuting so only about 6,000 miles per year are put on it. The car does not have power steering and is a three speed automatic. As stated above, the sound comes and goes in both frequency and loudness, it is not predictable. Any ideas?