Designed to allow stage performers to hear themselves properly, a floor monitor is an important feature in a live situation for accurate vocal tuning and timing, and for the use of acoustic instruments.
Also known as wedges, or foldbacks, a floor monitor unit is fed from a separate mix supplied by the desk or front of house system, which is equalised to highlight just the required vocals or instrument and nothing else.
They differ from normal PA speakers in that their cabinets are designed to lay horizontally, and the front panels are angled up towards the performer, usually at around 30 degrees. They generally feature a two way system of woofer and tweeter, which tend to be high power 12 inch drivers and bullet tweeters to allow accurate clear sound reproduction at any volume.
Construction on many monitors has generally stayed with the traditional wood and carpet pairing rather than the newer polycab materials. This is partly for the tighter bass and midrange on offer from the wooden enclosure, but also due to its absorption of the other amplified signals on a live stage that could cause vibration issues in a lighter weight cabinet.
Monitors are available in Passive and Active types, and choice of which to buy is dependant on your intended usage, and the equipment you already have. A small band or mobile solo performer obviously has very different needs from their system compared to a full stage installation, so will often often go for the ease of use provided by an active unit, whereas a school, church, theatre or college will often have amplifiers and crossover units as part of a main system so would only require a standard passive unit.