The album's producer, Steve Albini, provided the microphones, an Electro-Voice PL20 and two vintage Lomo 19A9's. "They're irreplaceable," Albini said. "They stopped being microphones and now they're artifacts. I feel like I should get them into the hands of somebody who would take care of them and not put them at risk in the hectic environment of a recording studio."
In a video interview accompanying the news, Albini said he realized the microphones' significance after seeing them in a Bob Weston photo taken during the In Utero sessions at Pachyderm Studios and included in the LP's 20th anniversary reissue package. The picture shows the setup Kurt Cobain used to record his vocals, with the Electro-Voice and one of the Lomo microphones situated next to a music stand holding the hand-written lyrics to "Rape Me" (the set-up also included a third microphone, though Albini said he was unable to identify it in his collection). Albini also used both Lomo microphones as overheads to record Dave Grohl's drum tracks.
Albini said he consulted Grohl and Nirvana's other surviving member, bassist Krist Novoselic, about the sale before putting the mics up for auction. "As soon as I was aware that these things had become important and significant and valuable, I had to take them out of circulation in the studio," he said.
Reverb will host two separate auctions, one for the Electro-Voice PL20 and another for the two Lomo 19A9s. Both lots will include the microphones' power supplies and cabling. Reverb primarily serves as a marketplace for buying and selling music gear and only hosts auctions for special items.