S ometimes ‘less’ is ‘more’. For ‘prepared piano’, you don't necessarily need to throw all sorts of heavy hardware, and car keys, bolts, screws, weatherstripping, and other violent junk into your piano and treat your piano like a percussionist’s rubbish bin.
F or one thing, the piano suffers. For another thing, the sonic consequences are just too extreme, and draw the audience’s attention to the performer and to the outrageous thing the performer has done to the piano, and detract from the audience’s actually listening to the music that the prepared instrument makes. Sometimes, instead of a visual ‘spectacle’ or sonically ‘provocative stunt’, the comparatively subtle acoustic effect you want can be gotten just by inserting some tiny objects that are gentle to the piano and that can be as easy to apply and remove as, say, a mute on a violin or other stringed instrument is easy to apply and remove.
T he do-it-yourself widgets below don’t ‘mute’ anything though. They dramatically change the pitch of each string they are applied to—from a few tens of ‘cents’, up to as much as a major sixth.
A nd you can’t create this sort of note-by-note harmonic effect with Pianoteq® or other synths; those establish harmonic attributes globally, applying them across the entire keyboard, not note-by-note.
F irst get yourself some Sugru®. It comes in a wide variety of colors, not just the orange that appears in the pictures here.
N ext, get yourself some 5 mm OD brass tubing and 5 mm OD brass archery nocking points (see links below). Also get yourself some 22 AWG copper wire, or whatever convenient gauge is slightly smaller than the diameters of the various piano wires where you intend to place the nocks.
T hen with your Dremel® handtool fitted with an abrasive saw (circle disc), cut your brass tubing to the lengths you want.
I have used tubing lengths from 30 mm to 70 mm to create weights ranging from 3 gm to 7 gm. For strings in the bass register, obviously you can use larger-diameter brass tubing.
E ach Allen Co (Broomfield CO) nocking point (Part No. 540) weighs about 400 mg when its lumen is filled with Sugru® silicone rubber.
N ext, cut one lengthwise slit in the side of each segment of brass tube with the Dremel® handtool.
C ut pieces of copper wire with a wire cutter or snips, about 2 cm longer than the length of each brass tube or nock. Use a needlenose pliers to put a crook or loop in one end of each wire, so you will be able to easily grasp the wire between your thumb and index finger, and so you will also have a loop by which to hang each piece up in a safe place while the Sugru® cures. Alternatively, you can get a piece of florists’ foam or styro at a hobby shop and stick the straight end of the copper wire into it after the nocks have been penetrated by the wire.
L ay all of the brass bits and archery nocking points and copper wires out on your worktable on a piece of plastic or a plastic kitchen cutting board. This will faciliate clean-up and prevent the Sugru® from smudging any surface you care about.
O pen a 5 gm sachet of Sugru®. Roll it around in your fingers for a few seconds. It has the consistency of soft modeling clay at this point.
Y ou can press the Sugru® into the lumen of a brass bit with your fingers and trowel it nice and even with an artists’ spatula.
T hen take a copper wire of the length appropriate to that brass bit and gently push the straight end of the wire lengthwise through the Sugru® in the center of the lumen. The copper wire adheres to the fresh Sugru® a little, but you can easily poke the wire through, so that a centimeter or so of bare wire sticks out beyond the end of the nock/tube. Hang the wire with the Sugru® nock/tube (or insert the straight into florists’ foam) in a safe place where it can remain undisturbed for at least 24 hours.
C ontinue, filling each of the brass bits and penetrating their centers with the copper wires. Set your collection of Sugru® piano nocks aside in a cupboard—someplace at about 20°C (68°F) and away from sunlight.
F or your convenience, make a 5 mm ball of Sugru® and set it aside in the same location with the rest. Wait at least 24 hours for the Sugru® to cure. Pick up the 5 mm Sugru® ball and squeeze it. If it is firm, then you know that the curing process is complete and it is okay to proceed with the next step.
T ake a razor blade or X-acto® knife and cut radially, directly down to the copper wire. Mount each in turn in a PanaVise® or other suitable holder and slice the silicone in the lumen lengthwise, to enable the nock/tube to slide onto a piano string. Then gently rotate the copper wire loop clockwise and anticlockwise 45 degrees or so, to release the wire’s surface from its attachment to the Sugru® silicone. Pull lengthwise to extract the copper wire out of the silicone rubber hole it’s been embedded in. Use your X-Acto® knife to trim any excess Sugru® from the slit or the ends of each nock/tube.
H ere is how the Sugru®-filled brass tubes and bow-hunting archery nocking points look:
A nd the picture at the top of this post is how they look when you push the nocks and tubes on, their slits going over the piano wires so that each piano wire is seated in the center, in the cylindrical ‘cast’ made by the copper wire.
O n notes that have 2 or three strings, if you apply a tube or nock to one of the strings, you will create a sound where the weighted string is significantly lower in pitch than its companion string(s). In the upper register, my 3 gm to 7 gm tubes make the notes sound like Chinese bronze bells with the nipple-like bosses.
Y ou can slide the weight close to the middle of the string and it will mainly lower the fundamental and second harmonic of the string. If you move it nearer to the end of the string, it will lower the third and higher harmonics much more strongly.
I ’ve created a little Excel spreadsheet (link below), which helps you to calculate how much detuning you can expect as a function of changing the average mass of a string by adding weight to it. Obviously, this simple spreadsheet does not tell you anything about how the higher-order harmonics change, given that the weight is localized in a particular position on the string, not spread over its entire length.
P lease add comments below or email me to comment on your experiences with these Sugru® prepared-piano kluges.
- Sugru® moldable silicone rubber [methyltris(methylethylketoxime)-silane; gamma-aminopropyl triethoxysilane] (FormFormForm Ltd, 13 Hague St, London E2 6HN, U.K.)
- Allen #540 brass archery string nocking points
- Brass C260 seamless round tubing at SmallParts.com [3/16-in OD ~ 4.8 mm OD]
- Excel sheet, pitch as function of average string density
- Piano Technicians' Guild (PTG) website
- Pianoteq virtual piano synth
- DSM. Pianoteq: Virtual instrument with many uses. CMT blog, 03-DEC-2008.
- Bunger R (John Cage). The Well-Prepared Piano. Colorado Coll, 1973.
- Gann K. No Such Thing as Silence. Yale Univ, 2010.
- Nattiez J-J, Samuels R, eds. The Boulez-Cage Correspondence. Cambridge Univ, 1995.
- Surhone L, Tennoe M, Henssonow S, eds. Works for Prepared Piano by John Cage. BetaScript, 2010.