Diagnosing car sounds really isn't that hard. Just requires some simple application of deductive logic.
For example, does the sound change rhythm and pitch to the engine rpm regardless of vehicle speed? Then the problem is probably with the engine. Unless the sound goes away when the clutch is engaged, then the problem is in the transmission (assuming a manual, this is because the transmission stops spinning when the clutch is in and the car is at a stop).
Does the sound change according to vehicle speed regardless of engine speed? Then the problem is in the wheels/axles/brakes (everything before the output side of the transmission). If it's a whir, whine, or clicking, then problem is likely in the axles, joints, or differential(s). If it's a metal-on-metal grinding noise, then the problem is likely in the brakes or hubs. Does the sound change under braking? If not, then it's the wheel bearings.
Now, I'm not there and haven't heard these sounds, and am just basing my assumptions on what the OP said, but I am showing how I came to my conclusion. Judge or critique as you will.
Sorry, OP, cars suck sometimes. If you really want to test the brake possibility, find a safe area (like an empty parking lot) and do some really quick stops down from about 20 mph. Lock 'em up even once or twice. Then go in reverse a few feet after each run. If the sound doesn't change during or after, then the problem is likely not the brakes.