Loose belt will also cause a noise like that. Simple check, pull the belt and run the car for a few seconds, see if it still makes the noise. If the belt is worn, go ahead and replace the tensioner and the idler pulley. These have springs and/or bearings inside and are wear items. Careful on the idler pulley, make sure to get the correct size. Parts stores will say it's a 90MM pulley but it's more like a 72mm or 74mm or something, can't remember the exact size. Mine needed the smaller one. Noise will also travel in funny ways, so what sounds like is coming from the intake, may not be.