"In jazz, we accent the off beat," says Juan Tony Guzman, a charismatic jazz musician and educator from the Dominican Republic.
"Swing, get the swing, get the swing, get the swing, get the .," he half-sings, half-says, demonstrating the ride rhythm. "That is the rhythmic foundation to create the swing feeling."
The room is populated by glockenspiels, xylophones, a piano and 12 rather non-swinging looking teachers who are now snapping fingers on beats two and four, shaking maracas and tapping out the ride rhythm on cymbal.
Mr Guzman, who is director of jazz at Luther College in Decorah, Iowa, is presenting the Orff approach to music teachers from both primary and secondary.
The Orff approach to music education, also known as Orff-Schul-werk or Music for Children, was conceived by the German composer Carl Orff.
The method, which involves speech patterns, rhythmic sequences, singing and simple tonal constructions and variations on percussion instruments, is largely improvisational. Orff saw percussive rhythm as a natural basic form of human expression, and discouraged mechanical drill which, he felt, stifled creativity.
Advocates believe the system builds confidence in children, boosts creative thinking and facilitates group working. Less confident children, says Mr Guzman, respond particularly well, since everyone of any ability can join in.
He instructs the group to create the "E blues scale" by removing all Cs and Fs, moving Bs up one step to where the Cs were, and inserting B flats between the As and Bs. Everybody has a little play, experimenting with the blues scale, then Mr Guzman goes through a couple of blues licks - short melodic sequences - which can be used as a reference for improvisation or as the basis of riffs for accompaniments.
After an explanation and demonstration of the 12-bar blues, the room is aswing with Duke Ellington's E Bar Blues. One group is playing the base line on metallophone, another the tune and a third another treble line, while others play the ride rhythm and jazz beat.
"It's a very simple harmonic structure: E, E, E, E; A, A, E, E; B, A, E, E," he explains. "This note sequence corresponds to the form of the blues: three phrases, each four bars long. Words and music follow the same sequence."
Mr Guzman introduces the group to Huddie Ledbetter's "Good Morning Blues".
"We have a statement, then we repeat that statement, then we have a conclusion, which completes the thought," he explains.
"You can pick a theme and improvise and the students can make up words to fit the tune. For the melody, you may consider some blues licks or develop new melodic ideas derived from the blues scale. Students will respond when they are involved in the process."
A marriage of major and minor melody is introduced as the final stage. "You don't normally get major and minor together but in the blues they work together beautifully," he says.
The Orff approach draws out children's natural affinities for rhythm and melody, and enables them to progress at their own pace, says Mr Guzman: "It is our job as teachers of music to inspire students."
Laureen Hier, who teaches children from pre-school up to the age of seven at Kilcreggan Primary near Helensburgh, says: "You can't be wrong, which is really good.
"Some of the more able kids can do the trickier stuff, while some can keep the beat going on the percussion. And they can all have fun experimenting because it all sounds fine with the blues scale.
"I wouldn't have known how to do that. The kids will love it."
The session was part of the Scottish Association for Music Education's Power of Music conference in Stirling earlier this month