The network for Canada’s community of improvisational and new music practitioners is growing, and Halifax’s annual Open Waters Festival is a vital link in a chain that stretches from Sound Symposium in St. John’s, N.L., to Vancouver’s New Music Festival.

Musician and composer Paul Cram, founder of Open Waters’ Upstream Music Association, saw a breakthrough in 2013 when he took the 20-piece Upstream Orchestra to Victoriaville’s International Festival Musique Actuelle, and this year sees a broader range of local, national and international performers and guests coming to Halifax for a weekend of brave new works and spur-of-the-moment inspiration.

“We’re getting our stuff out and the world’s stuff in; it’s a kind of reciprocity,” says Cram, who saw Open Waters begin in 1995 as a collaboration with Symphony Nova Scotia — whose performances bookend this year’s event on Thursday and Tuesday — before it was revamped as a festival in 2011 in conjunction with a new music conference.

“Festivals are events that stimulate conversation and ideas; even if you don’t love something, at least you’re able to discuss it,” says Cram, who’s looking forward to Saturday’s daytime events at Dal Arts Centre’s Dunn Theatre like the Improvisation Talk Back and the Dalhousie New Music Workshop.

The talk back session has its roots in the Guelph Jazz Festival, with six musicians on different instruments coming together for a collective improvisation with audience feedback. It was at such an event in Guelph where Cram first encountered one of the weekend’s featured guests, New York free jazz veteran Joe McPhee, who will perform Saturday at the Atlantica Hotel with Cram’s new group, Free Delivery.

Named after one of the Dartmouth musician’s earliest jazz ensemble compositions from 1977, Free Delivery has a solid lineup, including trumpeter Rick Waychesko, drummer Dave Burton and Danny Martin on trombone, all keyed up to join McPhee in a free-flowing exchange of musical ideas.

“We could easily go in there and do written material, and I’ve done that with these guys, but given the fact that we’re bringing in a guest and improvisation is his bag — and it’s our bag, too — I think we have a common denominator that we can work with,” says Cram.

“And people will see the contrast. Before us is Howard Beye’s new thing, Les Mecaniques de Nuit, combining Renaissance music with violinist James Southcott with a kind of rap, or a story. And after us is a duo from Quebec, Not the Music, with circular breather Philippe Lauzier and Eric Normand on bass, and it’s completely free, probably with some conversation beforehand.”

Expect some conversation Friday night at the Dunn with the Subscription Opus Duo from St. John’s, including percussionist (and Sound Symposium co-artistic director) Mack Furlong and soundsinger Chris Tonelli, performing a mail-art score by San Diego musician and composer Jude Weirmeir.

If you Google the composer’s name, plus “mail art” and the name of the piece, Maze Music, you’ll get a look at the visual score the duo will be working with. A friend of Weirmeir’s, who receives these pieces from him through the post as the Subscription Opus zine, Tonelli calls the scores “beautiful objects,” as fascinating to look at as they are to interpret on stage, inhabiting a grey area between music performance and performance art.

“I’ve been performing them for some time, and generally when I do, I invite people from the audience to come help me realize them,” says Tonelli.

“I like the spontaneity of those kinds of interactions, and these pieces lend themselves well to that.

“Mack happened to be in the audience one time when I was performing one piece called Hammer Music, for voice and hammer, and he came up and helped with the vocal part, and he really loved the piece and working on it, and that’s why we formed the duo.”

Looking at the score for Maze Music, which will be projected on a screen during the performance, you’ll see a music staff filled with video game characters like Donkey Kong and the Pac-Man ghosts, lines of poetry and vocal sound suggestions, and directions like “delirious bizarreness in the spider of the hand vibrates rhythm, rapidly ascending to the paroxysm of a beautiful, capricious mocking dementia.”

“It’s more of an inspiration than a dictation,” says Furlong.

“As you read through it, and follow us through the maze and see the things that come up on the screen, the audience is going to wonder what we’re going to do, and in some cases we’re going to wonder what to do.”

“There are some notation signposts in the piece where we have more or less something planned out to do as a duo, but even then, neither of us is really sure what the other person is going to be doing, even though we’ve spoken about it and rehearsed it. I think that openness to the possibility reflects the spirit of the Open Waters Festival, and it certainly reflects my desire to be in the moment whenever I play, not exactly sure of what’s going to be played until the moment has passed and we’re on to the next thing, worrying about that moment.”

Most of what’s performed at Open Waters can’t be repeated exactly the same way twice, but its founder hopes the nature of the experience will continue in new and exciting ways, in a

variety of new locations.

“All of this is for sale,” says Cram, who’s already planning a trio-themed Open Waters in 2016. “If we can get a festival rep from Zurich to invite one of these acts back to Europe, that’d be great. And some of the artists will share their experience here with other parts of the world.

“It’s putting Halifax on the map, of this particular kind of music. It’s taken a while, but we’ve really started something.”

Open Waters schedule

Thursday: Rebecca Cohn Auditorium: Symphony Nova Scotia, new music by Tim Brady plus Mozart and Haydn, 7:30 p.m.

Friday: Sir James Dunn Theatre: Alternating Currents with Tim Crofts, 7:30 p.m.; Norm Adams & Ellen Waterman, 8:15 p.m.; Subscription Opus Duo and subSet (Steven Naylor & Jeff Reilly) 9 p.m.; Night Coast Music, 10 p.m.

Saturday: Sir James Dunn Theatre: Improvisation Talk Back, 12:30 p.m.; Dalhousie New Music Workshop, 2:30 p.m.; Commons Room, Atlantica Hotel: Lukas Pearse, 7:30 p.m.; Les Mecaniques de Nuit, 8:15 p.m.; Free Delivery w. Joe McPhee, 9 p.m.; Not the Music, 9:45 p.m.; Riot Squad, 10:30 p.m.

Tuesday: Sir James Dunn Theatre: Symphony Nova Scotia presents new works by Jeffrey Ryan, Sofia Gubaidulina, Anton Werbern and Jerome Blais, 7:30 p.m.