With a one-sided conductive component the combined use of both the Weber and Rinne tests is useful. If the Weber test is used, in which a vibrating tuning fork is touched to the midline of the forehead, the person will hear the sound more loudly in the affected ear because background noise does not mask the hearing on this side. The following table compares sensorineural hearing loss to conductive:

Tympanometry
Tympanometry, or acoustic immitance testing, is a simple objective test of the ability of the middle ear to transmit sound waves from the outer ear to the middle ear and to the inner ear. This test is usually abnormal with conductive hearing loss. A type B tympanogram reveals a flat response, due to fluid in the middle ear (otitis media), or an eardrum perforation. A type C tympanogram indicates negative middle ear pressure, which is commonly seen in eustachian tube dysfunction. A type As tympanogram indicates a shallow compliance of the middle ear, which is commonly seen in otosclerosis. Audiometry
Pure tone audiometry, a standardized hearing test over a set of frequencies from 250 Hz to 8000 Hz, may be conducted by a medical doctor, audiologist or audiometrist, with the result plotted separately for each ear on an audiogram. The shape of the plot reveals the degree and nature of hearing loss, distinguishing conductive hearing loss from other kinds of hearing loss. A conductive hearing loss is characterized by a difference of at least 15 decibels between the air conduction threshold and bone conduction threshold at the same frequency.
Blocking of the eustachian tube leads to decreased pressure in the middle ear relative to the external ear, and this causes decreased motion of both the ossicles and the tympanic membrane. Acute or Serous otitis media
Chronic suppurative otitis media (CSOM)
Perforated eardrum
Tympanosclerosis or scarring of the eardrum
Cholesteatoma
Eustachian Tube Dysfunction, inflammation or mass within the nasal cavity, middle ear, or eustachian tube itself
Otosclerosis, abnormal growth of bone in or near the middle ear
Middle ear tumour
Ossicular discontinuity as a consequence of infection or temporal bone trauma
Congenital malformation of the ossicles. This can be an isolated phenomenon or can occur as part of a syndrome where development of the 1st and 2nd branchial arches is seen such as in Goldenhar syndrome, Treacher Collins syndrome, branchio-oto-renal syndrome etc. Barotrauma unequal air pressures in the external and middle ear. This can temporarily occur, for example, by the environmental pressure changes as when shifting altitude, or inside a train going into a tunnel. It is managed by any of various methods of ear clearing manoeuvres to equalize the pressures, like swallowing, yawning, or the Valsalva manoeuvre. More severe barotrauma can lead to middle ear fluid or even permanent sensorineural hearing loss. Inner ear
Third window effect caused by:

Superior canal dehiscence – which may require surgical correction. Enlarged vestibular aqueduct
Labyrinthine fistula

Presentation
Conductive hearing loss makes all sounds seem faint or muffled. The hearing loss is usually worse in lower frequencies. Congenital conductive hearing loss is identified through newborn hearing screening or may be identified because the baby has microtia or other facial abnormalities.