Readily available in most venues, stage monitors are a convenient option for musicians without touring sound systems. Each musician in a band can have a customized mix run through his own stage monitor. Stage monitors also help ensure that the stage sound is adequately loud and as balanced as possible. Although stage monitors are prone to feedback, simply moving back from the monitor or microphone can stop it.
The mix coming from stage monitors can leak into microphones, which can interfere with an audio engineer's ability to create a clear front mix. Stage monitors must also compete with one another. Amplifiers and drums must be audible and clear to each musician. Combined with the volume of each instrument, the stage sound can become very loud and dangerous to a musician's ears. Monitors are also prone to feedback and can negatively affect a musician's hearing.
In-ear monitors don't have to battle with instruments or other monitors, which benefits the main and monitor mix, as there is no unwanted sound leakage from monitor to microphone. This allows for improved sound clarity and for musicians to hear quiet and intricate elements of the mix. Click tracks can be played through in-ear monitors that help musicians keep better time. High-quality in-ear monitors block out on-stage sound, can be mixed quietly and are therefore less likely to cause hearing damage.
In-ear monitors isolate mixes and can therefore also create an environment in which musicians can't share a musical moment. Unidirectional microphones can be set up on stage to capture the stage ambiance, which can then be included in each monitor mix, but not every band has the equipment or expertise for this. In-ear monitors can damage hearing if they are too loud. These monitors can also feedback that can only be controlled by a limiting circuit, which complicates the mixing situation further.