Lou Marinaro has been teaching the ancient art of pouring bronze to A&D students for the past 28 years. Now engineering and music students want to get in the foundry.

They’ve come to the A&D studio to learn how to cast carillon bells for a course called Shaping the Sound of Bronze, a cross-disciplinary offering from the School of Art & Design, the School of Music, Theatre & Dance and the College of Engineering. The course is team taught by Lou Marinaro (A&D), Steven Ball (School of Music, Theatre & Dance) and Greg Wakefield (College of Engineering).

Steven Ball, Gregory Wakefield and Lou Marinaro. Paul Kominsky (far right)
was added to the faculty team to teach technical writing to the students.

Before this class, Lou Marinaro, though an expert in bronze pouring, had no idea how to make a beautiful sounding carillon bell. Steven Ball, on the other hand, is an expert in carillon bells and what makes them sound beautiful but has never poured metal in a bronze studio before. Greg Wakefield, an expert in signal processing and the physics of sound, could give you precise measurements about how to tune a bell, but also had no experience at all in making bells.

In truth, neither Lou Marinaro nor Greg Wakefield had thought much about carillon bells before last year. It was really Steve Ball, a professional carilloneur, whose passionate love for bells infected them all.  “Right now there is a very small handful of people in the world I can talk to about this. I thought, wouldn’t it be great if I could get other people to really hear what I hear? The university has so many resources, why don’t we pool our areas of expertise and make this happen?”

Steven teaches organ and campanology (the study of bells, their acoustics, history and manufacturing) at the University of Michigan School of Music, Theatre & Dance, one of the few places in North America where you can actually get a degree in Carillon Studies.  

The class tours the Lurie Bell Tower. Click to view full size.

The carillon program at U-M was the first of its kind in North America, founded in 1936, the same year that the Charles Baird Carillon was built inside Burton Tower. Generally speaking, it’s Europeans who are obsessed with carillons, the highest concentration being in Belgium and northern France, but the University of Michigan happens to boast two large carillon towers, one of which is the third heaviest in the world.

Still, a course that combines the study of carillon bells and the much more modern disciplines of signal processing and acoustics with actual bell casting and tuning is, as far as Steven knows, the only one of its kind in the world. In Europe, the closely guarded art of casting a good bell is shared by a few craftsmen and the making of bells is usually separate from carillon studies. “In my mind, the more you know about how an instrument is made, how sound really works: how timbre is created, how shaping the bell can effect decay, pitch and the beauty of the sound, the better player you will be.”

Since none of these three instructors had actually made a bronze bell this way before, they needed to test the concept before committing to a class offering. During the one-credit pilot course in the winter of 2010, Lou discovered they would need to obtain a special type of bronze, one that contained a lot more tin, for an acoustically vibrant ring tone.  

Convinced they could do it, the three professors got ready to offer the class in the fall of 2010. “The entire course was centered around having real bells to play on December 13th. We are North Campus, we make things here, the deadlines are real.” Greg Wakefield says.

Listed as a prerequisite choice for freshmen Engineering, the course is packed with mostly engineering students. The few A&D students in the class quickly became essential team members for their previous experience with bronze pouring.  “It felt good to offer this expertise, but I had so much to learn from the engineers in terms of applying the scientific method and the math behind this kind of making,” says Patrick Shamsuddoha, a junior at A&D.

The students would have 14 weeks to make a total of 9 bells that would form a full diatonic scale and some accidentals. (“This is actually referred to as a chime of bells,” Steve points out. “A full carillon has two octaves.”)

“We drew lots for what size (and what pitch) bell we would make,” says Erin Regan, an engineering freshman. “Our group drew an A bell but when we did the tuning test in the recording studio, it turned out it was closer to an F#. So we switched and worked on getting a perfectly in tune F# bell.”

Making a bronze sculpture that looks good is complicated enough. Making a bronze sculpture that also has to sound good is even trickier. The students had eight weeks to make the bells and 4 weeks to tune them.

Making the Bells: The First 8 Weeks

Students started by drawing their bell forms, and using these drawings to create jigs to shape the inside and outside walls of the bell..
Clay is shaped to form the outside wall of the bell and covered with a plaster mold.
The larger clay bell is removed and the smaller, interior clay bell is turned with a jig to make the interior wall.
Then, wax is poured to fill the space between the interior clay bell and the exterior plaster mold.
A gating system is added, and the mold is covered in a ceramic slurry.
The ceramic molds are heated to burn out the wax, as molten
bronze is brought up to 2150° Fahrenheit and poured in.
After the bronze has completely cooled, the molds are broken off and extra metal is removed from the bells.
Meanwhile, students had class lectures about acoustics and the physics and mathematics involved in frequencies and decay.

 

Tuning the Bells: The Last 4 Weeks

Once the bells were made, they needed to be tuned, a nerve-wracking process that involves precisely shaving the metal down in particular places using a lathe. “You have to be very careful, because obviously, you can take away metal but you can’t put it back,” says Steve Ball.

The bells were recorded in the Duderstadt Audio Studio for analysis, then tuned by removing metal.
Students hammer off the mold and listen to their bells for the first time.
Then they visit the audio studio in the Duderstadt to get a professional recording of the bell in order to later tune it.
Using the lathe to precisely shave the bronze bells.

Greg’s background in signal processing added some high technology to what had always been a traditional craft. The students used a modeling program to help them understand how changing the shape would effect the sound.

Greg Wakefield's program measures the frequencies of the bell strike and decay.

Even with expertise, skill, and technology, accidents can happen: not all of the bells turned out. Steve demonstrated a bell that looks fine but doesn’t sound right.

“This is an instance where Lou can look at the bell and say, 'it’s fine! It looks fine!', but I can hear there’s something wrong. It has a crack in it! Listen: no decay.”

Compare the decay on the first and second bells in this clip.
Steve thinks there is a crack in the first bell, which accounts for its short decay.

The Performance

In early December the bells were finally ready to be assembled into an "orchestra”.

“I’m surprised at how exciting this is!” says Steve.

Students practice on the finished bells.

 

Steve taught the group how to play four numbers, The Star Spangled Banner, Hail to the Victors, and, in keeping with the season, O Christmas Tree and Jingle Bells.

Click to view full size.

Finally, students presented documentation on the bell-making process and performed at Tishman Hall.

So here it is, the orchestra’s debut, on December 13th, 2010, performed on handmade bells made here at the University of Michigan. Steve laughs, "Next year we'll leave more time for practicing!"

Students perform Jingle Bells on bronze bells they made themselves in the course "Shaping the Sound of Bronze".

 

Images courtesy of Greg Wakefield.