It is a year since the death of the legendary and hugely influential artist Lou Reed. To commemorate his death and his legacy, here is an interview with one of his close friends and collaborators, the musician Sarth Calhoun.

How did you come to meet Lou? I understand you and Lou shared a passion for Chen Taiji? Was this something that kept the two of you close throughout your friendship - a combination of your passion for this and of course creating music?

Yes, Lou and I met through our common interest in Taiji, and it was always a through line in our relationship. We each studied the releatively rare kind of Tai Chi called Chen Style, and studied with Master Ren Guang Yi who is an unparalleled practitioner and teacher. I think the fact that a person would have the type of personality to seek out this kind of taiji shows a commonality between all of Master Ren's students. I After we had known each other a while he came and saw my band, Lucibel Crater, at the old Galapagos space in Brooklyn. He was interested in the electronic aspect of what I was doing, as he was exploring similar ideas with his Hudson River Wind Meditations. We started collaborating on mediation music for taiji, and things grew from there. We would do taiji together on tour, it really keeps you focused under ever-shifting conditions.

What would you say your favourite Velvet Underground album is? And your favourite Lou album?

My favourite Lou Reed album is The Raven... I can remember when we were mixing 'Power of the Heart' the engineer put on 'Guilty' as a way to give everyone a reference point for the room. I was blown away. I loved it totally and immediately. Lou told the story of how Ornette Coleman did several takes and how impossible it was to choose between them because each one was a work of genius. I think he may have released some of the alternates on his website in recent years. But I was also blown away by the groove! I turned to Lou and said "Who is that on bass?" He looked over and said "Me! ... of course it was, nobody else could play bass like that.

You played with Lou as part of the Metal Machine Trio. How did that come about exactly and did it feel liberating to play an album that originally divided critics, many years later for a live audience?

The Metal Machine Trio often gets conflated with the record Metal Machine Music but they are actually two completely distinct things. When we went out to play the first three shows with Ulrich Krieger in LA, it was just called "Unclassified" and later we named the trio Reed, Krieger, Calhoun but it was a mouthful. Metal Machine Trio had a much better ring and the music was in the spirit of that record, so it seemed fitting to go with that name. We released a live record of those first three shows, called Creation of the Universe and that should still be available from Lou's website. It was an absolute dream for me to tour that music, and I think that was true for all of us. Every night we played completely free improvised noise. We never had a discussion about what to play, it was just around 70-90 minutes and we would generally stop about 2/3 of the way through. This was a chance for all of us to explore something that was so close to our hearts, the way timbre is a kind of melody, painting pictures with sound as much as notes. I had an electronic rig I designed especially for this music, where I would feed Lou and Ulrich's sound in to my computers (and Kyma system) then I would sample and manipulate their sounds creating new melodies and ideas in realtime. It was never the same, and the music would radically evolve over the course of the tour. Every night, in a nod to the Metal Machine Music record, Lou and his tech, Stewart Hurwood, started the show with half an hour of meticulously tuned guitars leaned up against amps, feedback and drones with no-one on stage. Stewart has replicated that drone as an installation piece at The Kasher gallery in NY, and it was really moving. This was one of the greatest experiences of my life, and it changed me.

What was it like to work so closely with Lou and Metallica on Lulu?

This was another once in a lifetime experience. I listened to Metallica a lot growing up, so it was a big deal for me to have a chance to work with them. The material we brought consisted of compositions Lou and I wrote together for the play Lulu, as realized by Robert Wilson. These were more noise/abstract pieces, similar to the taiji meditation music or the Metal Machine Trio, but this time Lou put his astonishing lyrics over it. When it came to the Metallica record, we thought, what if we did Lulu? Metallica was totally game and watching them work was incredible. They are some of the most accomplished and creative musicians I have worked with before or since. I was floored every second they were playing. Standing in the room with them, watching them do their thing totally raised the bar in my mind about what is possible for a band to be. They aren't just incredible, they make it look effortless.

As someone who knew him well, how was it to work with Lou? I imagine it was an absolute joy? Some journalists didn't think so though, at their own peril.

It was a joy. Lou truly loved music, and people loved working with him because you always knew exactly where he was coming from. He valued great work and led everyone to a place where they could be their best. Now, if you have a rare opportunity to talk with a great artist and you squander it asking nonsense ... I am surprised artists put up with any of it.

The Gralbum Collective is a wonderful idea - please tell me a little about it, and also what kind of releases we can expect in the future?

The Gralbum Collective is reimagining the record as immersive art. The name came from GRAphic novel meets concept aLBUM. Some people like to listen to music while they do other things, but I want that deeper, more involved experience, and for that a different format is necessary. Gralbums invite you to focus on the music, the art, and the story. I originally had the idea partly because Lou curated this amazing slideshow for the NY Photo Festival at St. Anns Warehouse in Brooklyn. He set it to three of our (as yet unreleased) taiji/meditation tracks and I was struck by how different the music sounded with the visual context. I started working on The Book of Sarth after that, as well as a collaboration with Lou designed specifically for this format. It occurred to me a lot of other musicians and artists like to work in mixed media so we approached some likely candidates and they were immediately interested.

Beatboxer Adam Matta who is also an animator and visual artist, put together an amazing, unified piece called SKETCHES. Cellist/vocalist Leah Coloff with three songs from her upcoming record, THIS TREE, matched with 3D rotations of these handmade sculptures she does, they are insane, cardboard boxes with quilting inside and old photographs, as well as a music video and the oil paintings of artist Robert Lucy. That Leah one is just one preview Gralbum but it goes to so many different worlds. Then we have this great one called Train O Thots which has all these drawings of people in the subway... years of drawings this guy did, Tom Hart, and Moon Hooch was generous enough to contribute the music. Plus we have one from Billy Martin (of MMW) who is also a visual artist who displays in galleries, you know, he did the original MMW logo. We have one coming from the Dithyrambalina project which is this crazy musical architecture thing in New Orleans, and the tracks we are using are Thurston Moore and the artwork is from the actual buildings and instruments themselves, including a bunch of cool stencils by Swoon.

That's the stuff we've confirmed, but we have more surprises coming. Honestly, I wonder if I would have thought of this idea had I not met Lou. He was such a brilliant artist, and he always encouraged people to push themselves to the limit. That's what I'm trying to do with Gralbum.

In celebration of White Light/White Heat by The Velvet Underground.