I have Falken Azenis 225/45R17 running on 43psi and max is 50psi...yesterday night, i was hitting 120 on the fwy and i noticed a hum coming from my car

. it only made it at that speed because as soon as i slowed down, it would go away and come back when i would hit 120 again. i'm assuming its prob the tires. anyone had this prob before??? could it be anything else???...and i don't often hit that kind of speed

Please help. tnx everyone for any info.