Songs in the Key of X was released on March 19, 1996. The album also spent five weeks in the Swedish
Sverigetopplistan charts, peaking at number 42, and six weeks in the
Finland's Official List chart, peaking at number 24. Reviews for
Songs in the Key of X were generally positive. Upon the album's release,
Entertainment Weeklys David Browne rated it a B, calling it "easily the most ambitious record ever assembled for a TV soundtrack". Browne felt that the contributions to the album by Sheryl Crow and William S. Burroughs were amongst its highlights, though felt that the compilation was "dragged down by ponderous contributions" from Nick Cave and Elvis Costello.
AllMusic's Steven McDonald was mostly positive towards the album, rating it three stars out of five and stating that "while not perfect, the album makes a nice alternative compilation", noting that it shares the television series' "blue-light glow of twisted mystery". McDonald felt that the Foo Fighters cover of Gary Numan's "Down in the Park" and Elvis Costello's "My Dark Life", along with Mark Snow's theme for the series, were the highlights of the compilation. Sandy Masuo, writing for the
Los Angeles Times, rated the album three-and-a-half stars out of four, finding that the compilation's "unsettling ambience" suited the "deliciously creepy" atmosphere of the series. Masuo felt that the R.E.M./Burroughs and Costello/Eno collaborations ultimately turned out to be "more interesting in theory than in practice", naming "Down in the Park" as the best track on the compilation, with the contributions of Rob Zombie, Alice Cooper and P.M. Dawn also noted as highlights. A review for the album in
The Independent noted that none of the songs "can really hold a candle to Cave's 'Red Right Hand' in capturing the show's sense of fatalistic futility", adding that there seemed to be "a shared soul thing" between Cave and Carter. Ted Cox, writing for the
Daily Herald, described the album as "a who's who of modern rock". Cox rated the album three stars out of five, noting that "most of the material hits the fair-to-middling quality level of a neglected album cut or a good
B-side", adding, however, that the album's overall "atmosphere of paranoia and alienation" helped to tie it together. Writing for
The Buffalo News, Anthony rated the album four stars out of five, calling it "a strange, delightful trip". felt that "Star Me Kitten" was the album's best song, and that Danzig's "Deep" was its "weakest cut". Writing for the
Los Angeles Daily News, Fred Shuster felt that compared to other television tie-ins that "aren't worth the aluminum they're recorded on",
Songs in the Key of X "is a rare exception because of the unusual quality and rarity of the tracks". Shuster rated the album three stars out of five, describing it as "more imaginative than the show that inspired it". ==Track listing==