For example, a 1000 Hz tone in an unaffected ear may be heard as a slightly different pitch in the opposite ear, or have an imperfect tonal quality in the affected ear. Biological explanation via theories of pitch of pure tones
There are two theories on the cause of diplacusis: place theory and temporal theory. Place theory posits that  the cause is looking for the edge of the wave for the pitch and could explain diplacusis as a small differences between the two cochleas.Temporal theory posits that the cause is from looking at the phase locking to tell what the pitch is. This theory has a difficult time explaining diplacusis. There are some examples of pitch which do not have an "edge" on the basilar membrane, which this would account for—e.g., white noise, clicks, etc. Both theories are under debate. Effects of sensorineural hearing loss
Normal human ears can discriminate between two frequencies that differ by as little as 0.2%. If one ear has normal thresholds while the other has sensorineural hearing loss (SNHL),  diplacusis may be present, as much as 15–20% (for example 200 Hz one ear => 240 Hz in the other). The pitch may be difficult to match because the SNHL ear hears the sound "fuzzy". Bilateral SNHL gives less diplacusis, but pitch distortions may persist. This may cause problems with music and speech understanding. Treatment
Treatment of diplacusis includes a full medical and audiological examination that may explain the nature of the problem. If needed, amplification may relieve the symptoms of diplacusis.
Therapy in helping the patient understand the cause of the symptom and tinnitus retraining may provide some relief. In at least some cases, amplification makes no difference and there is no treatment other than waiting for natural resolution. Some individuals may find the provided amplification also increases the audibility of their pitch discrepancy. If onset is linked to an underlying medical cause, i.e. sudden sensorineural hearing loss, appropriate medical treatment is recommended. Etymology
Diplacusis is from the Greek words "diplous" (double) and "akousis" (hearing). See also
Hearing
Hearing loss
Pitch (psychophysics)
Auditory system

External sources
Diplacusis: I. Historical Review
Turner, Christopher. "Perception of Pitch." Wendell Johnson Speech and Hearing Center, Iowa City. Dec. 2008. Plack et al. (ed.). Pitch : Neural coding and perception. Springer. 2005. == References ==