T. Hallenbeck: Projects: Electric Cello 4 (Page 7)

thallenbeck.com :: Projects :: Electric Cello #4

Bracing system

March 30, 2008: brace pieces done.

The instrument is shaped like a cricket bat with strings. It's playable, but without some sort of bracing system to hold it at the proper position and angle, the player would be a hunchback in a week.

The bracing system has to:

Hold the the instrument at a position and angle that will imitate the dimensions of a real cello.
Provide the three contact points where a real cello touches the player's body: upper chest, and insides of both knees.
Have an end pin of adjustable length that touches the floor.
Be detachable and modular so that it will fit into a carrying case along with the instrument.
Be relatively strong and rigid.
Be relatively light.

At right is a photo of the late, great Mstislav Rostropovich, at Checkpoint Charlie when the Berlin Wall came down. I'll use this photo as an example of a real cellist playing a real cello. Not how the fingerboard and bridge are several inches away from his body. Also, note how the endpin floats the instrument.

Most cello endpins extend parallel to the plane of the instrument. Note the angle of the endpin in the photo. It's decidedly not parallel to the plane of the instrument. Rostropovich was notorious for this construction tweak, which was considered unusual. Here at Hallenbeck Labs, we consider it good and will emulate it, for reasons discussed below.

Referring to the photo below:

From the front, the brace is cross-shaped. The vertical section (middle in photo) aligns with the body of the instrument. The crosspiece (bottom in photo) bolts to the vertical section at a 90-degree angle. The end pin (top in the photo) slots into the bottom of the vertical section.

The vertical section is angled back at the top and the bottom to provide contact points in the proper positions. The piece that looks like a cane handle at top of the vertical section is shaped roughly to the dimensions of the back of a real cello at the neck heel, where the instrument rests against the player's upper chest. The bottom of the vertical section is angled back to simulate the way a real cello balances on its end pin.

When I built a wooden model of this, I had the end pin extending straight out, and it didn't feel right that way - the end pin of a real cello touches the floor closer to the player's feet. To me anyway, the overall arc shape of the vertical section seems to mimic the dimensions of a real cello. Thus the emulation of the 'Rostropovich angle.'

I dismantled the strings, bridge, and tailpiece to fit the instrument for the brace, shown below. The piece with the pointed end at the top is an endpin for a double bass, probably stainless steel, which I modified, that is, gouged holes in, for this project. The other two pieces are TIG-welded plain steel, mostly square tubing and scrap I got cheap. All three pieces are spray-painted black.

The piece with the pointed end at the top is an endpin for a double bass, probably stainless steel, which I modified, that is, gouged holes in, for this project. The other two pieces are TIG-welded plain steel, mostly square tubing and scrap I got cheap. All three pieces are spray-painted black.

I drilled holes in the endpin to acommodate a set pin.

This is the part of the brace that rests against the player's upper chest. I bent a piece of square steel tubing and welded it to the upper end of the vertical section to mimic how a real cello feels. This part makes contact with the player's body behind the neck heel.

This is the part of the brace that rests against the inside of the player's knees. It's part of the crosspiece that attaches to the vertical section. I cut two similarly-shaped pieces of sheet steel, bent them in something like an S shape, and welded them to opposite ends of some square steel tubing about 15 inches long. I made the sheet pieces irregular to allow for variation since the crosspiece can be attached to the vertical piece in four possible positions - the asymmetry increases the probablility that the player will find at least one of the positions comfortable.

The brace section bolts to the back of the instrument and is of course removable. The sleeve on the bottom side of the instrument is for the tailpiece.

This award-winning shot shows the instrument mounted on the brace. The vertical section is bolted to the back - note the curved piece peeking out behind the top section of the body and upper left. The crosspiece section is bolted to the vertical section. The endpin slides inside the lower end of the vertical section and is held in place by the set pin. Better photos of the brace later... after I clean up the huge mess I've made in the basement.

The final tweak to the brace will be rubber or foam of some sort over the parts that make contact with the player's body.

Next: Final assembly and tweaks