Intro:
The purpose of this project is to explore transduction and composition/digital production using a homemade inductor coil pickup. This type of pickup is the kind used in electric guitars, but our intent is to use the pickup in unconventional ways to explore how interesting signals can be audibly represented. Once we have audio samples of these signals, we will use a DAW to produce a “symphony” of these sounds. The project can be divided into several stages: 1) Research, 2) Building, 3) Experimentation, 4) Analysis and Digital Manipulation.
Research:
In researching various types of pickups and how they are constructed, we found a simple yet effective design that operates using the same basic principles as a guitar’s pickup. The specific type of pickup that we chose to create is an Inductor Coil Pickup. The design of this pickup consists of a strong magnet which is wrapped tightly by a very thin, enamel coated wire. The purpose of the enamel covered wire is to transfer the current along the length of the coil, as opposed to passing the current sideways between the wires. We learned in class that the coils of a magnetic pickup are capable of detecting the disturbances in the electrical field as signal waves interact through the process of induction, and that by connecting the ends of a coil to an amplification system, we can hear these systems – or, should we connect the output cables of the coil system into an audio interface, we can record the signals.
During research, we found that these pickups are capable of detecting much more than just the vibrations of a string – they are capable of picking up the normally inaudible frequencies, such as those from the infrared spectrum, that are emitted from everyday electronics (phones, remotes, modems, etc.), effectively allowing us to record and make audible signals that are otherwise inaudible to the human ear.
Building:
To construct our pickup, we will use: 42 gauge AWG wire, a neodymium magnet, acrylic or some comparable non-ferrous material, and a quarter-inch TRS plug. The magnet will first be secured between two small plates of acrylic. Additionally, a hand-drill will be placed in a vice, and the acrylic and magnet unit will be place on the end of the drill. When the drill is turned on, the unit will spin. We will then the secure one end of the wire to a small hole in the acrylic, and begin wrapping the wire around the magnet with the help of the drill. Once we have achieved sufficient wrapping, the other end of the wire will be secured to the acrylic. Additional wire will be used to create a cable with the TRS plug on the end. Once these steps are complete, we should be ready to begin using the pickup in the experimentation phase. This is the tutorial on which we have based our building procedure: https://www.youtube.com/watch?v=u6f-H_-C-2Y
Experimentation:
This phase of the project will be highly subject to change as we learn which uses produce audio and which fall flat. However, at this point in time, we hope to use the pickup to listen to the internal activities of various electronics. This video demonstrates some of the sounds we’d like to explore ourselves: https://www.youtube.com/watch?v=iIQKhPpNPE0 (1:52). Additionally, we are considering putting the pickup inside of a ferrous object (like a tin can), and seeing how being in such a space might alter the signal prior to it being received by the pickup.
Analysis and Digital Manipulation:
We will use various DAWs to analyze the signals recorded through the coil, such as Audacity (to perform spectral, frequency and other analyses) and Ableton or ProTools (to create the piece using these new samples).
This seems like it has the potential of getting some really cool sounds – I especially liked the hard drive and laptop noises in your linked video. You could maybe also try “listening” to a CD player or tape player, or appliances like a fridge or a washing machine. I’m looking forward to hearing what you come up with!
We think those noises are really cool too, but there’s one issue we’ve been thinking about: the pickup we’re building includes a very strong permanent magnet, and we’re worried it will destroy a laptop if we put it close too it….So we are still definitely in the brainstorming phase of what kinds of sounds we should use it to “listen” to.
This all seems so cool! Especially because I don’t know much about transduction. The one thing that I wasn’t clear on is is the deliverable the varying analyses of the different scenarios? And if so, how will you be comparing the different analyses?
If you look at our second blog post, we include a link to a site with a bunch of different equations that could help us measure the inductance of our coil, or the current, and some other measurable things like that 🙂
I am super excited to hear what comes of this. I love the idea of building a musical piece from the bottom up like this, constructing your own equipment for capturing sound and then trying to use it in untraditional ways. I have never thought to take guitar pickups out of their typical context, so I really like this idea.
Yeah! We actually got the idea from Reddit…someone wrote that they had put a guitar pickup inside a copper tube (a ferrous material that could vibrate when exposed to sound) and used it sort of like a microphone to capture sounds through the “filter” of the tube. We are planning to start by using our pickup to try to “listen” to electronic devices, but we are also toying with the idea of mounting the pickup in a ferrous tube of some sort (tin can?) to see if we get any interesting signals.
Very cool project! One thing that could help with construction: Jim has a coil winder in his lab. That could (a) make winding easier and (b) make it more precise (has a turns counter)