The liner notes to the original LP cover and recent CD reissues of the album state that it was "captured live on an Ampex stereo cassette fed from a Kelsey Morris custom built mixer ... in the rain from the back of a Volkswagen truck."

Atlantic Records, the original distributor for King Crimson in the United States and Canada, declined to release Earthbound because of its poor sound.

[2] In his book A New Day Yesterday: UK Progressive Rock & the 70s (2020), Mike Barnes describes Earthbound as a "rather ropey sounding" document of the harder-edged performances that King Crimson played on their US tour subsequent to Islands (1971).

Noting the infamy of its "utterly non-digital genesis" as a cassette-recorded album, Jones believes that "its 'official bootleg' ambience sits strangely in the canon of a band infamous for their sonic precision.

"[10] Jones believes that "Peoria" is the closest King Crimson ever got to funk, chiefly due to Collins' sax and Burrell's scat singing, and considers "Groon" to be "one of the most adventurous things [the band] ever attempted".

Planer adds that the "quartet's strength as improvisational members of a cohesive central unit are amply displayed throughout every sonic twist and turn.".

[11] Dan Nooger of The Village Voice recommends the album to those who are interested in hearing a "goodly portion" of the tour it was recorded on, in which King Crimson "rewarded us with furious pure music of almost unbearable intensity.

"[18] Discoveries writer Chris Nickson writes that on Earthbound, "King Crimson had certainly gone for the physical", but believed that its cheap price was justified "given its appalling sound."

"[22] In a 2014 list for The Quietus, Mika Vainio from the group Pan Sonic named Earthbound among his thirteen favourite albums, crediting it for helping him discover a wealth of jazz and progressive rock.