Plotting membrane speakers
Overview
Project for wire plotting of membrane speakers. for wildcard week in mas.836 2018
- Sam Calisch
- Elena Chong
- Zijun Wei
- Victoria Shen
We will use a custom magnet wire plotting tool for the Zund cutter to plot coils for audio speakers.
TODO
waterjet steel layers- laser cut shim layer (500um? 1mm?).
- test heat+vacuum for membrane layers (sam)
- verify magnet orientations with gaussmeter.
- modify coil cutout to extend beyond frame for easy stretching, run job (sam)
- solder leads (mount RCA jack?)
- test with audio amp
optional
- do a version with 1/16" magnets and 1/16" phenolic layer
Simulation
Two approaches: Coil-magnet, and coil-coil.
Coil-coil
The coil-coil topology relies on coils to generate all magnetic fields, not just the time varying one.
Magnet-coil
The coil-magnet topology (planar magnetic) is used for some high end headphones. It can produce significantly more force than coil-coil, even with very thin magnets.
magnet grids
In our meeting this morning, we talked about how rod magnets are more widely available than long, thin bar magnets, and that making grids of rod magnets could make assembly really easy and offer design freedom. Below are two sketches of square and hex grids with coils routed to capture perpendicular flux. Magnets are blue circles, all closest pairs have opposite polarity.
The design below has rotational symmetry, which may help flatten its frequency response.
Watching the coils being plotted is fun: