Conductive hearing loss is a phenomenon in which there's some blockage in the External Ear Canal (EAC) preventing the transmission of sounds from the air (AC-Air Conduction) to the oval window of the inner ear creating signal transmission to the Cranial Nerve VIII.
~By Qt


References:
https://books.google.com/books?id=si1Bm6bJhhQC&pg=PA1073&dq=weber+test&hl=en&sa=X&ved=0ahUKEwjZo5TgoZ3SAhVPyWMKHT6aCpwQ6AEIJzAD#v=onepage&q=weber%20test&f=false