Kreen-Akrore tribespeople of the Brazilian Amazon, after he had watched an ATV documentary on their way of life. Amid musical interludes featuring electric guitar, organ and piano, McCartney used a bow and arrow he purchased at the Knightsbridge department store Harrods, according to engineer Robin Black. The latter was among the few people who knew that McCartney was making a solo album. Linda contributed the breathing and animal-like sounds, with McCartney, on "Kreen-Akrore". EMI Studios, February–March 1970 On 21 February 1970, McCartney moved to the more familiar EMI Studios, with the booking again under the name of Billy Martin. There, he carried out further mixing on the previously recorded material, as well as taping new selections. On 22 February, McCartney recorded "Every Night" – another composition rehearsed during the Get Back sessions, and a song that authors Chip Madinger and Mark Easter note as the "first 'professional' recording" on the finished album, given its position as track 4, following "Valentine Day". The same day McCartney recorded "Maybe I'm Amazed", a piano-based ballad dedicated to Linda, and, in Madinger and Easter's description, "the most elaborate instrumental track on the LP". The final new recording for McCartney was "Man We Was Lonely", which he taped on 25 February, having composed it earlier that day. It is the track on the album on which Linda's vocals are most audible. Final mixes of songs such as "Junk" and "Teddy Boy" were completed at Morgan Studios along with the remaining tracks on the album. During this process, "Hot as Sun" and "Glasses" were segued into a medley, ending with a snippet of McCartney performing the song "Suicide" on piano. Unacknowledged in the track listing for the album, "Suicide" was a composition that he had intended for Frank Sinatra to record. He also edited two separate instrumental pieces into one for "Momma Miss America"; McCartney can be heard shouting the first portion's original title, "Rock 'n' Roll Springtime", on the recording. On 23 March, while American producer Phil Spector began mixing the Get Back tapes for release as the Beatles' Let It Be album in EMI's Studio 4, McCartney completed work on his album in Studio 2. Although McCartney has frequently maintained that he was ignorant of Spector's involvement until receiving an acetate copy of Let It Be for approval, author Peter Doggett writes that after "several weeks", McCartney had finally "answered the string of messages