Final answer:
A bearing noise that gets louder with speed and is unaffected by turning likely indicates bad wheel bearings. Wheel bearings allow the wheel to spin freely, and when they wear out, they produce a grinding noise that increases with speed.
Step-by-step explanation:
If a bearing noise only gets louder with speed and is not affected by turning, it may indicate that the wheel bearings are bad. Wheel bearings are designed to enable the wheel to spin freely and with minimal friction. When bearings wear out, they tend to make a grinding or growling noise that increases in volume as the vehicle's speed increases. This is because the damaged bearings are not as smooth as they should be, causing more noise as the wheels turn faster.
Signs of a bad wheel bearing can sometimes be subtle, but the key characteristic is the change in noise level with speed, rather than with changing direction. If turning the steering wheel doesn't affect the sound, this typically rules out issues related to directional components like CV joints or front differential issues in vehicles with all-wheel drive.