What is an ALD (Assisted Listening Device) recording?
Bootleggers can request an ALD (Assisted Listening Device) headset at an arena concert (required by law for hearing impaired fans), which provides a high-quality feed of a live show using a low-level FM frequency broadcast inside a facility. Bootleggers will tape this headset feed, giving the bootleg not usual problems like random crowd noise or distortion.
What is an IEM (In Ear Monitors) recording?
In Ear Monitors are devices used by performers to hear a mix of microphones and/or instrument pickups that are on the stage. They are often custom fitted to the individuals ears and provide a high level of noise reduction from stage noise. An IEM recording is a recording of this wireless audio feed, there can be a difference between an IEM recording from Bono's feed and the recording from Adam's for instance.
