SOUND VOLTEX (officially abbreviated as SDVX) is the newest member of Konami's Bemani series of Rhythm Games. Its a variation of beatmania with pretty much identical gameplay, in regards to the "hit the keys when they hit the line" part (but thenagain, aren't most rhythm games similar to that in the first place?). But instead of the familiar piano keys, it uses four square buttons in a row, accompanied by two larger "FX" buttons directly below them, along with effector knobs on both sides (which you must either slowly rotate in a certain direction, or quickly slam between sides).The other big distinction is that most of its soundtrack consists mostly of remixes of songs from other Bemani games by doujin musicians; but through Downloadable Content, this aspect quickly went out of control as the game began to be flooded with Vocaloid songs and Touhou remixes (and even long-time meme songs like "Bad Apple", "Help me, ERINNNNNN!!", and even the Nyan Cat song!).There are currently two games in the series:
Sound Voltex Booth (2012)
Sound Voltex II: Infinite Infection (2013) Released as an online update, making it the first BEMANI game to be released in this manner rather than through an upgrade kit. Unlike Booth, where bottom notes can only be hold notes and top notes can only be tap notes, both rows of notes can either be tap or hold notes. Sound Voltex II also introduces the Infinite difficulty, available only on specific songs.
Sound Voltex III Gravity Wars (TBA)
Sound Voltex songs are considered licensed songs, and therefore traditional Sound Voltex soundtracks are not available. However, there is an album of Touhou remixes featured in the series available for purchase: SOUND VOLTEX ULTIMATE TRACKS -Touhou Koumakyou REMIX-, which is a compilation of songs chosen from the Touhou Project EOSDnote Embodiment of Scarlet Devil Remix Contest.
Touhou has a particularly large presence, featuring Appeal Cards of the characters and over 50 Touhou arranges. In fact, Sound Voltex II had a location test at the Touhou-centric Reitaisai 10 convention in 2013. It certainly helps that Mayumi Morinaga, a prominent BEMANI vocalist, is also a vocalist for Touhou arrange circle Yuuhei Satellite. There are so many Touhou arranges that they get their own category in SDVX II.
As far as BEMANI crossovers go, generally subverted in that most songs that make it over to SDVX get remixed, often by a artist contributing via Sound Voltex Floor.
Played straight with the POLICY BREAK and FLOOR INFECTION events beginning in SDVX II. POLICY BREAK is a type of SDVX event in which songs are crossed over from other BEMANI games and left in original form (excluding in-game filters). Examples include "VALLIS-NERIA", "I'm So Happy", and "BabeL ~Next Story~". FLOOR INFECTION is a type of event for other BEMANI games, which goes the other way: Sound Voltex songs get crossed over to other BEMANI games. Examples include "Joyeuse" in GITADORA and "Max Burning!!" in Reflec Beat.
Double Unlock: Infinite-difficulty charts require you to fulfill another condition before you are allowed to purchase them.
Doujinshi: Doujin music is a major staple of the series.
In normal play, you get a special Life Meter called the "Effective Rate". It doesn't end the game if you hit 1%, but you do need to end the song with the meter at 70% or higher to pass.
In Skill Analyzer, you get a straight lifebar, the "Permissive Rate", that results in a TRACK CRASH if it hits 0% at any point.
Another straight lifebar is available in normal play, called the "Excessive Rate", with a higher penalty for missing. In Gravity Wars, reaching 0% on this gauge will switch you over to the standard Effective Rate gauge instead of resulting in a TRACK CRASH.
Lost Forever: POLICY BREAK songs can only be unlocked for two weeks each. Fail to unlock a song during its availability period and they can't be unlocked anymore, although it may come back in a future update.
Sequel Difficulty Spike: The maximum difficulty level was previously 15. However, during the Sound Voltex II tournament at KAC 2013 in December, two songs with Exhaust charts rated level 16 were introduced to the finalists: "Bangin' Burst" and "For UltraPlayers". Both songs were added for non-tournament play later that month. A third level 16 chart, "Max Burning!!" on Infinite, was added in September 2014.
Vocaloid: as noted above some of the songs use them.