Dual 18" Subwoofer Nik Heiser, Music Production & Recording Arts nik.heiser@gmaiL.COM

  • Sponsor - Dr. Jeremy Hohertz, Lecturer in Physics
The Woodworking Process

I wanted to build subwoofer to serve as an example of speaker design for my professional resume. As I pursue a career in live audio, an understanding of speaker technology will be incredibly important. Furthermore, many live audio companies also work as speaker manufacturers or retailers.

There is also a small subculture centered around Hi-Fi, Custom Sound Systems, mainly within the culture of Electronic Dance Music. As an EDM and audio enthusiast, I have always desired my own subwoofer, and decided to build one fitted to my needs.

Carpentry in the Theatre Shop!

PROCESS:

  1. Research
  2. Design
  3. Build
  4. Test
Rough Sketch

RESEARCH:

  • Drivers: Thiele-Small Parameters, Parallel v. Series
  • Amplifiers: Wattage, Ohms, Features (Power, High/Low Pass, Stereo v. Mono)
  • Ports: Round v. Rectangle, Tuning, Calculations
  • Enclosures: Sealed v. Unsealed, Material, Bandpass, Bracing, etc.
  • Physics of Sound: Modes, Frequency & SPL, Wavelength, etc.
WinISP Enclosure Design Software

DESIGN:

  • Enclosure Design: WinISP
  • 3D Modeling: Fusion 360
  • 2D Modeing: AutoCAD

My enclosure design was based around my desired frequency response and SPL, dictating box size, port size, and port tuning. I wanted to maintain a fairly flat, full-range response, while also achieving minimum peak SPL levels between 95-100dB. This led me to use 4 ports, tuned to 28.5Hz.

I also had to design the circuitry connecting my amplifier and drivers. Due to the resistance and power rating of my amplifier, I chose to wire the 2 18" drivers in Parallel. In this circuit I used 2 x Fane Studio Colossus 18B Subwoofer Drivers & a STPAS600-D plate amplifier.

Fusion 360 & AutoCAD Design Softwares

BUILD:

  • CNC - VCarve Software
  • Refine Cuts - Various Tools
  • Assemble Enclosure - Various Tools
  • Assemble Circuitry
CNC
Assembly

TEST:

  • Frequency Response
  • SPL Curve
  • Phase
  • Polar Pattern/Dispersion

All testing done via RoomEQ Wizard and a dbx RTA-M Reference Microphone.

WHAT I LEARNED:

  • Speaker Design: Various physics principles, mathematical formulas, understanding of Thiele-Small Parameters, Port Tuning, etc.
  • Software: WinISP, Fusion 360, AutoCAD, VCarve, RoomEQ Wizard
  • Carpentry
  • Design Thinking

VALUABLE RESOURCES:

  • The Maker Hub!
  • The Theatre Shop - Technical Director Luis Silva and Assistant Technical Director Anthony Cacchione
  • My Sponsor - Dr. Jeremy Hohertz
  • Youtube - Educational Tutorials
  • Loudspeaker Design Cookbook
  • diyAudio Forum