Question: The band whose style is typified by the blurring of component musical parts was formed when?

Context paragraphs:
Portal (band): Portal is an Australian extreme metal band whose style is an unorthodox fusion of death metal with black metal.  The band's hybrid musical style is characterised by heavily distorted guitar riffs, down-tuned rhythms, and vocals ranging from "menacing, echoing" sound effects to guttural grunts.  Writing for "Popmatters", Adrien Begrand noted that "death metal always pretends to be scary, but [...] it's all rather harmless.  That said, however, I make no mistake in saying that the death metal peddled by Australia’s Portal is truly friggin' terrifying".  Lead guitarist Horror Illogium has described Portal's intent as "to capture a cinematic horror scope".  They have released four full-length albums to date, as well as a number of EPs and split releases.  Their most recent album, "Vexovoid", was released in February 2013 on Profound Lore Records.

Four-part harmony: The term "four-part harmony" refers to music written for four voices or for some other musical medium—four musical instruments or a single keyboard instrument, for example—where the various musical parts can give a different note for each chord of the music.

Weekend (American band): Weekend is an American lo-fi or shoegaze trio from San Francisco, California.  The band formed in 2009 and released two EPs, with the full-length debut album "Sports" coming on Slumberland Records in 2010.  The album received an 8.2 rating from Pitchfork Media.  It also received 4/5 stars on Tinymixtapes and was also reviewed by National Public Radio, the "Portland Mercury", "Boston Phoenix", "NME", Drowned in Sound, Brooklyn Vegan, The Onion's AV Club, and PopMatters.

The Mountains and the Trees: The Mountains and the Trees is a Canadian folk rock band whose sole constant member is Jon Janes of Pasadena, Newfoundland and Labrador.  The band is now based in St. John's.  Canadian singer-songwriter Hayden is a significant musical influence.  In addition to Hayden, the musical style has also been likened to that of Iron & Wine and Julie Doiron.  Critical reception has been generally positive.  Rachel Sanders of "Exclaim! " wrote, "[Janes'] thoroughly modern folk style combines traditional instrumentation with subtle but perfectly integrated effects."

Ádammo: Adammo was a Peruvian rock band whose style, described as Power pop that combines hard rock with a touch of melodic rock Adamm achieved consolidated as the pioneer of power pop band in Latin America.  The band name comes from a Greek dialect which means "Pleasure to do something", in this case pleasure of making music.

Eden's Bridge: Eden's Bridge is a Christian band whose style covers elements of Celtic folk, pop, and rock.

Folkhop: Folkhop is a genre of music that came about after the death of Bhangra in the mid 1990s.  It is diametrically opposed to Bhangra music in that it is not a live music but instead relies on pre recorded musical parts with only the vocals being sung live along to a live repetitive dhol drum.  The pre recorded music consists of primarily looped rhythm parts from both eastern and western percussion instruments and little to no melody on instruments.  It borrows heavily from hip hop, however it is more traditional than its predecessor, Bhangra which rebelled against tradition and authenticity.  Traditional folk instruments like dhol and tumbi are central to folkhop productions.  Folkhop songs tend to be heavily produced by DJs on computer software.  In the beginning, all songs start out as vocal only recordings that the folk singer records in India.  This 'vocal only' recording is then sold on websites involved in the buying and selling of folkhop music.  The DJs then pay a small sum for the rights to these vocals, and then set the music using looped samples of both hip hop and traditional folk instruments.  The quintessential folkhop artist is the bedroom DJ.

A. D. Grover: Albert Deane Grover (18 February 1865 Boston, Massachusetts — 23 October 1927 Manhattan, New York) was an American banjoist, composer, teacher, and prolific inventor of musical parts and accessories for stringed instruments.  He was a founding member of the Boston Ideal Banjo, Mandolin and Guitar Club.  Grover held over 50 patents for musical instrument parts, and founded the musical accessories company A. D. Grover & Son.  His father, Stephen Grover (1820–1885), was a Boston piano maker.

Shoegazing: Shoegazing (also known as shoegaze) is a subgenre of indie rock, alternative rock, and neo-psychedelia that emerged in the United Kingdom in the late 1980s.  The style is typified by the blurring of component musical parts—typically significant guitar distortion, feedback and obscured vocals—into indistinguishable mixtures of sound.

Alter Ego (Peruvian band): Alter Ego is the original Peruvian neo-progressive rock band whose style goes from the ever-changing art rock from the 1990s mixed with new sounds from the 1970s.  Their style crosses between symphonic rock, hard rock to power ballads and R&B.  The band was founded in 1992 by pianist/composer and lead singer Juan Carlos Oganes in Perú (South America), who assembled five other musicians and developed a sound that was rare for the time in that part of the world.  They combined much of the anthem-type compositions of Juan Carlos Oganes with nice and lush vocal harmonies in the style of Queen and Yes.  The album was produced by him and recorded at Emporium Digital Studios.  Alter Ego paid much attention to theatrics and used the cinematographic expertise of Oganes -to create a sense of audiovisual entertainment.  Oganes also directed their videos.  They recorded much material since their first years and many of those songs ended in their 1997 debut album called "Utopia".

Supporting paragraphs: Weekend (American band) Shoegazing
Answer: 2009