Frank Zappa was not one to mince words or hand out praise to people who didn't earn it.

As genuinely funny as Frank was, he took his craft about as seriously as can be, and he expected the same commitment from the musicians he collaborated with. If something was amiss, Frank's would correct it in kind.

Steve Vai was just 20 when he moved to California to work for Frank, eventually getting a chance to join Frank's band. While the maestro surely appreciated having a prodigy in his midst, Vai still had plenty of blind spots when it came to recording and being in a band.

Speaking with Australian Musician editor Greg Phillips about the new documentary film, Zappa, Vai recalled one of many revelatory conversations with Frank that still serves him today. Phillips asked Vai how much Frank offered input on the equipment his band members used.

"I was very inexperienced when it came to tone because I never could afford a good amplifier," Vai said of those early days. "I gave precious little attention to tone. I remember ... after the first show that I ever did with Frank, I met him in the restaurant of the hotel in the morning — we were having breakfast. And I said, 'So, how was it?' (Laughs) And he said, 'You know, Steve, I think you're a really good musician, but your tone sounds like an electric ham sandwich.'"

Frank was typically forthright when it came to his music, but Vai couldn't quite wrap his head around the comment — or how to correct it. At 20 years old, he spent most of his guitar years, learning music, transcribing and sharpening techniques. He'd yet to sit down and devote time to sculpting the sound that actually came out of the speakers.

"And I said, 'Well, why? I've got the [Fender] Strat, I've got the Marshall [amplifier]...'" Via continued. "And this is profound, and it's true and I've used it my whole life, and I go into great detail. Frank never went into great detail. He would just say things and they were unequivocal. He said, 'The sound isn't in the amps; it's in your head.'

"At first I didn't know what he meant by that; I thought it was just some esoteric, cool thing to say. It wasn't until a little later on that I realized, 'Yeah, that's exactly where your tone is. It cannot be any other place.' It's going to sound the way you're expecting it to sound and then you'll manipulate it to get it where you want it to sound. I gave very little attention to that. I gave little attention to a lot of things before I joined Frank's band, and then I focused intensely on various things through his tutelage."