Neil Young masterminded the new Buffalo Springfield box set What's That Sound? – but didn’t tell former bandmate Stephen Stills about it.

Stills only discovered that the set was due for release in June when he was asked to comment on it. “They forgot to to tell me,” Stills told Rolling Stone, explaining that he couldn’t answer specific questions because he hadn’t heard the new versions. “The first I heard of it was when I got the notice that you were going to interview me last night. … They will have it in my hands shortly.”

Young described What’s That Sound? as “the greatest Buffalo Springfield collection ever” on his website, after he and Stills had worked on an earlier set in 2001. “I heard they fought with the first album [1966’s self-titled LP] a lot because, basically, we had four tracks and four knobs,” Stills said in the new interview. “Engineers back then … were very conservative and they wouldn't push the equipment. The Beatles did okay with four tracks and we were trying, but we found our best mixes back then to be the mono. When Neil and [producer/engineer] John Hanlon tried to spread it out, they ran into some very strange separations.”

Stills recalled hearing the first album again in 2010. “I walked in and it was appallingly fast," he said. "I couldn't believe it. I said, ‘I can't listen to that!’ Pro Tools has a thing in it where you can feed the record into it and slow it down without changing the record a bit, plus it does really wonderful things to the bass. I hope they employed that because songs like ‘Go and Say Goodbye’ and the shuffle called ‘Leave’ got really heavy and Stones-y because that's the way we played it live, but we went into the studio and [drummer] Dewey [Martin] counted everything off, and Dewey was from Nashville, so you do the math.”

Buffalo Springfield never got around to professionally recording any live performances, which Stills said he regrets. “The best sound we ever got was when we did this stupid TV show where we played just a little bit of a song and we were like, ‘Oh, my God, that's the sound we've been looking for’,” he recalled (perhaps referring to the band's appearance on detective show Mannix in 1967). “It was the only place we could get that sound right.”

What’s That Sound will be released as a five LPs, five CDs and digital formats on June 29.