The
Nautilus
Sketching
Ceramics
Acoustics
Rhino + Grasshopper
Fusion 360
INDUSTRIAL DESIGN
The Nautilus uses a series of spiraling waveguides to propagate sound from the rear of the speaker to enhance sound quality and bass extension. It's a new take on the cornu spiral speaker design usually seen made of foam-core and hot glue.
Instead, we mounted our 6" speaker driver into a 3D printed housing using a self-centering mount design.
A clear acrylic front panel ensures that unlike other cornu spiral speakers — you can actually see the spiral.
6" Reference Woofer
M4 Machine Screws
M4 Threaded Inserts
1/4" Acrylic Cover
1/4" - 20 Nuts
3D Printed Housing
Speaker Mount
Mounting Plate
1/4" - 20 machine screws
The speaker body rests on a 3D printed ceramic base made using an ABB IRB4600-60 robot arm with a clay extruding end effector.
DESIGN PROCESS
KEY AREAS FOR DESIGN EXPLORATION
HIFI SPEAKER DESIGN PHILOSOPHIES
Rear-Loaded Horn
Horn
Omni-Directional
Ported Ceramic
CORNU SPIRAL
The Cornu Spiral speaker is a very obscure speaker design from the forum diyaudio. It uses a series of radiating waveguides to channel the air behind the driver. This is a similar concept to the Rear-Loaded Horn but turned 90°.
This design reportedly greatly enhances the sound quality of small full-range speaker drivers.
Usually made from foam board and hot glue, the design has never been commercialised leaving room for exploration.
DESIGN ITERATIONS
We made an enclosure using foam board and a sheet of acrylic. Using a headphone amplifier we tested the speaker with and without the enclosure.
We found that although the driver was pretty bad to begin with and the amp was too weak to fully drive the speaker, there was a small but noticeable improvement with the enclosure.
Iteration 1
We made an enclosure using foam board and a sheet of acrylic. Using a headphone amplifier we tested the speaker with and without the enclosure.We found that although the driver was pretty bad to begin with and the amp was too weak to fully drive the speaker, there was a small but noticeable improvement with the enclosure.
Instead of eyeballing the curvature, we 3D printed the waveguides to replicate the actual curvature of a Cornu spiral. Additionally, we used a 3" full-range driver and home theatre amplifier to give ourselves better results.
While the sound quality was improved significantly, we found that the bass was mostly directed towards the sides.
We designed a complex series of smooth internal surfaces which progressively reduce in depth to channel the bass both outward and forward.
The acrylic cover encloses the spirals, creating a horn effect. It was deliberately sized down to allow for more sound to go forward. This greatly improved the tonal balance and clarity of the sound.
CLASS A SURFACE DESIGN
Using Rhino and some Grasshopper we were able to create smooth swept class A surfaces between each waveguide, resulting in a highly efficient transmission lines (the spaces between each waveguide). This resulted in a unique aesthetic that was entirely performance driven.
CERAMIC BASE INFILL
Unlike a regular 3D print, we couldn't just slice our model in Cura and send it to the printer. Instead, we had to manually create surface and infill geometry to be sliced in a custom Grasshopper script.
This outputted RAPID code for use with the ABB robot arm through RobotStudio.
CERAMIC 3D PRINTING EXPERIMENTS
Experiment 1
We first tried to print a small section of the spirals out of clay but quickly ran into issues.
Unlike traditional plastic 3D printing, the clay took days instead of seconds to dry. It therefore could not achieve overhangs and required extensive custom radial infill to support outer surfaces.
Experiment 2
In our first attempt to print the base we found that the infill was far too dense.
In addition to a double walled design and the solid bottom surface, this led to the model needing to be split into 3 parts due to the amount of RAPID code generated.
Experiment 3
In our first attempt to print the base we found that the infill was far too dense.
In addition to a double walled design and the solid bottom surface, this led to the model needing to be split into 3 parts due to the amount of RAPID code generated.
