later, Mark Boston joined the band as full-time bassist. The lineup of Van Vliet, Harkleroad, Cotton, French, and Boston recorded the rest of the tracks, with Van Vliet's cousin Victor Hayden occasionally guesting on bass clarinet and vocals. Zappa originally proposed to record the album as an "ethnic field recording" in the house where the band lived. Working with Zappa and engineer Dick Kunc, the band recorded some provisional backing tracks at the Woodland Hills house, with sound separation obtained simply by having different instruments in different rooms. Zappa thought these provisional recordings turned out well, but Van Vliet became suspicious that Zappa was trying to record the album on the cheap and insisted on using a professional studio. Zappa would say of Van Vliet's approach that it was "impossible to tell him why things should be such and such a way. It seemed to me that if he was going to create a unique object, that the best thing for me to do was to keep my mouth shut as much as possible and just let him do whatever he wanted to do whether I thought it was wrong or not." "Hair Pie: Bake 1", one of the tracks recorded by Zappa and Kunc at the house, appeared on the finished album. Three other tracks on the album were recorded on a cassette recorder at the house, the a cappella poems "The Dust Blows Forward 'n The Dust Blows Back" and "Orange Claw Hammer", and the improvised blues "China Pig" with former Magic Band member Doug Moon accompanying Van Vliet on guitar. "The Blimp" was recorded by Zappa in his studio while on the phone with Van Vliet prior to the album's sessions; Jeff Cotton was put on the phone to recite Van Vliet's latest poem, which Zappa recorded and put over a Mothers of Invention backing track (which had been known to the Mothers, unacknowledged on Trout Masks credits, as "Charles Ives"). When they entered the studio, the band completed twenty instrumental tracks in a single six-hour recording session. Van Vliet spent the next few days overdubbing the vocals. Instead of singing while monitoring the instrumental tracks over headphones, he heard only the slight sound leakage through the studio window. As a result, the vocals are only vaguely in sync with the instrumental backing; when asked later about synchronization, he remarked, "That's what they do before a commando