1999 Chevy Venture humming sound

Sounds like a wheel bearing. You can determine which side it's coming from. Steering either left or right, the noise or hum should increase or decrease. If the noise gets worse when you turn the vehicle to the right, then the left bearing needs replaing, (steering to the right puts more weight on the left front wheel). If the noise gets worse when you turn the vehicle to the left, then the right bearing needs replaing, (steering to the left puts more weight on the right front wheel).