Typically a static/hum/hissing sound in the infrared headset is caused by one of the following events:
1) One of the RCA cables (red/white) is connected into an input rather than an output or the 3.5 mm connection has been plugged into a digital output rather than an analog output. To resolution is to make sure the audio cable is connected into analog audio outputs.
2) There is some form of interference with the infrared beam of light from an external source (ie: a lamp or other form of light is disrupting the infrared light). The resolution is to remove this external interference. NOTE: If the unit is connected to an LED or plasma TV the light from the screen can actually be causing the interference and we would recommend switching to a radio frequency (RF) model rather than use an infrared model.
3) The hiss is being created by the audio connections themselves through a faulty connection. The resolution is to try the unit on a separate independent audio source (like a cable box, DVD player, iPad, stereo, etc). If the unit works correctly on the new audio source you can then determine that the issue lies with the original audio connections and new connections with the original audio source need to be established. NOTE: For testing purposes we would recommend connecting directly to the audio source with the 3.5 mm connection on the audio cable as it is possible that a faulty 3.5 mm to RCA adapter could cause the issue.
4) The audio signal itself is corrupted and the hiss is actually part of the audio signal. This typically occurs when a cable signal is involved. The resolution is to call the cable company and request that the audio signal is reset.