Rock Band 3 allows for 1–7 players, either locally or through online game services, to use various instrument controllers to accurately simulate the playing of music. In addition to supporting the four Basic instrument controllers from previous Rock Band games (lead guitar, bass guitar, drums and vocals), Rock Band 3 adds support for two additional microphones for singers to provide backup vocal harmonies (previously found in The Beatles: Rock Band and Green Day: Rock Band), an electric keyboard as a new instrument (or any MIDI-compatible keyboard), plus support for a specially made 102-button MIDI bass, and an actual Squier guitar by Fender. Support for MIDI compatible electronic drum kits as well.
Prior to a song, each band member selects from one of four difficulty levels, Easy, Medium, Hard, and Expert, which influence the number and rate that notes appear on the note track; they also can select the Pro mode for real guitar, bass, keyboards, and drums. As the band performs, they score points. Each player can build up a multiplier by hitting consecutive notes correctly, which increases how many points each note is worth, but the multiplier is set back to 1× if a note is missed. After successfully completing a song, the performance of each player and the band as a whole is rated on a 5-star scale. The best performance by a player for each song in the player's library is tracked separately based on instrument, Basic or Pro mode, and difficulty, then is used to provide and compare leaderboard statistics at the end of the song.[4]
The overall goal of the band is to successfully complete a song and earn as many points as possible by using their selected controllers to play the notes shown on the screen at the proper time; or, in the case of the vocalists, to sing in relative pitch to the original artist. Players can also gain additional points by using "Overdrive". Once a player has enough energy, which is collected by perfectly playing marked sections of the song, he or she can activate Overdrive to double the number of points the whole band earns while it is deployed. Each instrument deploys overdrive differently, and some instruments have multiple methods of activating it.
In point competitive mode (without the "no-fail" option on — not recommended for Pro mode), players who are doing poorly might be forced to drop out of the band, which silences their part temporarily while the rest of the players continue to play. A dropped player can be saved up to two times by another player activating Overdrive; if the player is not saved soon enough, the whole band may fail the song and need to restart or exit to the song library. In some game modes, an option is also available to continue the song right from where the band failed at the cost of not being able to record a score for the rest of the song's playthrough.
Although Rock Band 3's gameplay in Basic mode is very similar to that of previous games in the series, it does introduce a new gameplay mechanic designed to make fast sections such as trills, tremolo picking, and drum rolls easier to play. In such sections, players are rewarded for being exactly on cue, but they are not penalized for small differences.[5]
