Piano and cello have been a popular combination of instruments since the time of Beethoven. Many composers felt all but obligated to write their own in Ludwig’s wake.

But pianist Christopher O’Riley and cellist Matt Haimovitz, who perform together at Weber State University Friday, like to play songs that weren’t expressly written for the cello/piano setup.

They make splendid work of them, plus a few personal favorites in the classical repertoire, on their album “Shuffle.Play.Listen,” due out from Oxingale Records on Sept. 27.

O’Riley, who also hosts National Public Radio’s young classical artist show “From the Top” (which will record at Weber State University in March), wanted a chance to collaborate with Grammy-winning cellist Haimovitz, with the latter pushing the boundary of his instrument’s voice by making it sound like a violin, an electric guitar, and any number of human singers.

O’Riley included arrangements of songs by artists ranging from the Cocteau Twins and Radiohead, to Igor Stravinsky and Arcade Fire. He also arranged a large portion of the film score from Hitchcock’s “Vertigo,” written by Bernard Hermann for violins, rather than their low-voiced cello cousin.

“What I was gravitating toward was this — it is easy to say that the cello is the best imitator of the human voice,” said O’Riley, calling from his home in Ohio. “But I wanted a lot of different voice textures. Thom Yorke (of Radiohead), he is sort of a crooner, the Frank Sinatra of his time, but on the whiney side. And with the Cocteau Twins, you have a kind of operatic soprano with a lot of filigree. The woman from Blonde Redhead is fragile-voiced. I wanted all those different things in there, and I knew Matt could do it.”

Two CDs

O’Riley and Haimovitz didn’t set out to make a two-CD set, one featuring music with a more modern classical feel, and one covering various types of rock and pop.

“We had a lot of songs we wanted to do,” said O’Riley. “And we discussed it, should we do these things separately, because the pop CD became its own entity. But then the whole idea of this concert tour was mixing and matching the repertoire.”

Calling from his home in Massachusetts, Haimovitz added: “We thought we’d make a CD, and then in concert, we’d just go between these two worlds. But there was so much music we wanted to include, it was hard to decide what to leave off. I don’t even know who had the idea to make it a two-CD set, but there was the answer.”

Haimovitz said that their hopes for the CD are reflected in the name, “Play.Shuffle.Listen.” Ideally, he said, they’d like the listener first to listen top to bottom, from the first track on the first CD to the last track on the second CD.

After that, they can stack the songs in their MP3 player and let them shuffle at will, and mingle.

“Kind of like what you will hear on our tour — we will be in shuffle mode,” said Haimovitz. “The idea we have is that the audience that is out there listens to a range of genres, so this will be exciting for them.”

Experimenting

Haimovitz said he enjoyed the challenges of the vocals that O’Riley threw his way. He said the Mahavishnu Orchestra piece, where he imitated the “voice” of John McLaughlin’s guitar, was probably easiest for him, because he is a huge McLaughlin fan and has played his material in the past.

He laughed. “I know all about how to turn a cello into an electric guitar.”

But some of the other lines he had to play took actual invention of sounds on his cello — even working at odds against what he has learned as a young player.

“In Blonde Redhead, for instance, you have a very delicate-sounding Japanese singer, and I try to emulate the spirit of what she does,” said Haimovitz, speaking of singer Kazu Makino. “I could not dig in with her as much as other voices — I had to look for something more ethereal, use portamento, which is kind of sliding around the notes. I had to not quite press the finger all the way down to the fingerboard, as you are taught to do from the beginning to get a pure sound. But I wanted something not too pure, to let in some of that noise.”

Such a collaboration might not have worked with many musicians of this caliber. But with O’Riley and Haimovitz, there is a shared adventurous spirit, and a tremendous amount of respect and trust.

“I think Matt has raised the bar with this recording, so far as cello technique — he has, just by getting through that Hermann piece! I don’t think most people would even recognize it as being cello for most of it, and he makes it sound amazing,” said O’Riley.

Said Haimovitz: “To have someone like Chris — where he is so sensitive, and also such a wonderful musician, someone who can just sing on the piano — is rare. But he can also transform the piano into a rhythm section and create different textures I can respond to. I feel at home with him.”