It sounds like hot metal expanding.It is not the brakes but it only occurs when l brake and comes from both sides. It used to do it only after it warms up but now seems to do it as soon as l start driving.I've had a couple of different mechanics look at it but can not figure it out.l replaced both upper ball joints, too.l am at a loss at what it can be.

Look, it may be calipers,brakes,rotor,pads.Some cheap pads make a noise like this when they ''glaze''.This is caused by the pads heating up look at pads to see if
the side that sits on the rotor to see if they are shiny. If it is not
the brake system it may be the hub bearings. They run around 300 a piece.Good Luck