The cello I use is amplified. This allows me to magnify otherwise inaudible sounds, such as those that are made with a very light physical attack. I have found that these sorts of actions usually produce more sonically detailed, textured, and multi-phonic sounds than when I use a more heavy bow attack. Amplification makes it possible to produce an entirely different sound world from an acoustic instrument, simply by widening the dynamic range.
Additionally, the pickup on the bridge turns the whole instrument into a microphone. I use a Memory Man analog delay mainly to soften the otherwise brittle sound of the transducer (piezo) pickup and to thicken up the sound a tiny bit by running the signal through a vintage analog circuit- I avoid obvious effected “delay/ echo” sounds. The analog delay overdrives very smoothy, allowing me to do what amounts to very crude live sampling; by turning up the feedback control while any sound is happening in the room I can “capture” it in infinite delay repeats and turn it into either a pure tone or an overdriven tone somewhere in its harmonic series.
I also use a lot of extended techniques, which are actions that are beyond the generally expected actions of a cellist (in other words, “wrong” things to do). The basic approach is to view the instrument directly and simply as an object that can be used to make sound. Some of the extended techniques I often use include bowing directly on the bridge or tailpiece, as well as making intermittent friction sounds on the body of the cello with the tensioning screw of the bow. I also put an excessive amount of rosin on the stick of the bow and use the sticky bumpy thing to make irregular rhythms as it is drawn.
By “preparation” I mean the addition of other objects to the instrument. I have two main preparations. One of these is a piece of metal strapping that I clamp to my bridge and bow or tap to create tones. It has a huge range of sound and is visible being bowed in the photo at the top of this page. This metal was found at a construction site for the fiscally infamous “Big Dig” here in Boston sometime in the late 90’s and was originally used to hold loose bricks together during transport. The other preparation is a system of sympathetic strings that I built onto the cello following inspiration from my experiences playing saragi (a HIndustani bowed instrument with 30+ sympathetic strings) and from seeing a Baryton (an 18th century European classical bowed instrument with sympathetic strings) in a museum in Vienna on the way home from my travels in India in the mid-90s. At that time I was an apprentice violin restorer; I set about building this instrument for myself thinking I would use the resonant strings in a standard way. I now have many pieces of metal (nail files, a metal file, street sweeper tines) stuck in between the strings. I use the resonant strings mostly for metal-on-metal friction sounds and the subtle amount of reverb they give. These strings run through the bridge of the cello and are amplified that way acoustically and also by the pickup.