TORONTO -- The first time Ghostface Killah heard BadBadNotGood's beats, he figured they were ancient soul samples likely performed by now-dusty musicians -- audio relics of some recently bygone era.

He certainly didn't expect the music was the organically instrumented work of three Canadian rap aficionados, so fresh-faced they were barely toddlers when his Wu-Tang Clan stormed the scene back in '93.

"I was amazed," he said, sinking into a leather couch at a Toronto studio. "I was surprised. I was looking at 'em and they was like, little guys -- with so much talent.

"I'm like, 'Y'all doing all of this, making it sound just like the record, and y'all are so young?"'

He's speaking just moments after wrapping a rehearsal with the band and Toronto producer Frank Dukes, who originally assembled all the parties. They released the 12-track collaborative blur "Sour Soul" this week.

BadBadNotGood -- the cheerfully low-key, jazz-school sharpened trio of Chester Hansen, Alex Sowinski and Matthew Tavares, all under age 25 -- actually began work on the production three years ago, swapping tracks back and forth, dressing songs around Ghost's gravelly linguistic buffet.

For this rehearsal, BadBadNotGood worked through a setlist that spanned Ghostface's gilded solo back catalogue, golden-age Wu-Tang and other random miscellany (Nas's "The World Is Yours," an Isley Brothers track).

For a trio of rap-reared Canadians, the session was deeply inspirational -- even before a sermon from the gruffly imaginative rapper.

"It was awesome: he gave us a 20-minute monologue during the rehearsal," said Hansen.

"It was about just being positive and living your life and not letting money get to you and keeping your friends close -- all that stuff."

Ever the storyteller, Ghost was still in a philosophical mood later.

The Iron Man has proven unusually rust-resistant in an industry -- and specifically, a genre -- known for fair-weather fickleness. Even his solo career is nearly 20 years old and has recently been marked by a streak of factory-line prolificacy.

"Sour Soul" represents his third record since December, if you count Wu's forever-gestating "A Better Tomorrow." Casually, he reels off the titles of three more Ghostface records he expects to come out before the sun sets on 2015.

"It's almost like you're a drug dealer," he explained. "They know you had the best weed out there, and then you just go missing, so they go to somebody else. You try to keep your clientele."

Unsatisfied, he tries another analogy.

"You know when you're jogging, you get tired but you're fighting it and you catch your second breath, your second wind? It feels like that."

It's closer to the first gasp for BadBadNotGood, who are so impossible-to-ruffle that they only seem starstruck when pressed, or by proxy.

Hansen, for instance, discovered Wu-Tang as he was hitting his teens, and shares his fandom with his brothers.

"Both of them are really stoked," he said. "My parents too, although they obviously don't have the same connection to Ghostface that we do."

The hand-stitched beats on this collaboration have inspired comparisons to Wu architect RZA, but Ghostface feels he needs to do more research before he can comment.

"I haven't listened to the album since (making it)," he said. "I don't listen to things I made like 'Supreme Clientele' -- I don't even think I got those. I do records and I leave 'em alone.

"Otherwise I always hear mistakes in my records."

Even absent that audio evidence, however, this jam session has made Ghostface a believer: BadBadNotGood truly has the goods.

"They got a big future in front of them," he said, shaking his head. "Big future."