Boris at Last -Feedbacker- (or simply called Feedbacker) is the sixth album by the Japanese experimental music band Boris. Much like their debut album Absolutego or Flood, Feedbacker consists of a single track which has been split into five parts on the disc. There is also an official DVD released on 2005 and limited to 500 which was released by Diwphalanx Records. This DVD was originally an unofficial recording of the band performing the entirety of "Feedbacker" live in New York and entitled Bootleg -Feedbacker-. The official DVD release depicts a different member of the band lying in a pool of blood similar to the album cover.
The album incorporates many different rock elements and because of it has become a song that the band frequently revisits on tour. On 13 September 2009, as a special set for the Flaming Lips-curated day of All Tomorrow's Parties New York 2009 in Monticello, Boris performed the album in its entirety. They performed the album again at the Pavement curated ATP at MineheadButlin's on 15 May 2010.
Written and released after the drone doom-meets-shoegaze one song album Flood and the stoner rock-based, song-centric, uptempo flavour of Heavy Rocks, feedbacker sought to unite the two sides of the same band in one song. Liberal use of the Roland Space Echo pervades the album, not only on guitars but also Atsuo's snare drum throughout. As with "Flood," only one song is listed, but it is split into 5 parts on the disc; each split corresponds to a movement. The first is a lengthy guitar drone introduction with Space Echo effects; the second, a shoegaze-style slow jam with the full band while Wata solos atop, first quiet and somber, then bridged with an echo-laden clean guitar refrain into an increasingly louder second solo, climaxing with Wata switching to loudly accompanying Takeshi's soaring lead guitar, which calms across the clean refrain into a vocal section; the third, a drone break leading to a stoner rock section with a quicker tempo and multiple riff changes with Takeshi switching to bass and singing lyrics, reminiscent of the style on Heavy Rocks; the fourth, a second, full-on noise drone crescendo and decrescendo that also distorts Atsuo's drums; and the fifth, a quiet return to movement II to finish the song.
The vinyl editions split the song in half, with side B beginning at CD track 3.