Australian Army Speaker Box

Australian Army Speaker Box


Project Category:
Portable Speakers

Project Level:

Project Time:
8-20 Hours

Project Cost:
$100 – $500

Project Description:
A portable, powerful and clear sounding speaker that fits inside a standard 5.56 Australian military ammo container

Design Goals:
To create something that doesn’t only look like it came from the military but for it to perform like it does too! Symmetrical, tough, and durable.

Driver Selection:
Dayton Audio RS100-4 4″ Reference Full-Range Driver 4 Ohm
Part # 295-378
Dayton Audio ND16FA-6 5/8″ Soft Dome Neodymium Tweeter
Part # 275-025

Enclosure Design:
The container has roughly 6L of airspace and the two main drivers required roughly 3L of airspace. Adding the batteries, mounts for the Amp and battery pack, wires, port, dampening material, two crossovers and the interface dish roughly reduced the airspace to just under 3L.

Enclosure Assembly:
Because everyone everywhere who knows anything about speaker design will tell you that building a speaker out of metal is a terrible idea, I decided to line as much of the inside as I could with timber and sound dampening material. Leaving very little metal exposed helped with reducing reverberation, and I still got to keep the rugged look of a freaking ammo container!
A side note. I never actually took a photo of the container with the dampening material inside, but fill it with as much as possible keeping in mind that air need to pass through it and the more you add the less total volume you have and you might actually be decreasing the performance of your speaker and over dampening it.

Tips & Tricks:
Being my first build I got some help online. Kirby Meets Audio on youtube supplied me with a crossover design, for a price. Parts express have a rather older video on youtube about putting together a DIY crossover which helped heaps. I managed to build the crossover but I’m not sure I entirely understand how or why it worked. Beginners luck?
The low pass should be 1300HZ and the high pass should be 4000HZ, both a 2nd-order Chebyshev. But those are just numbers and words to me.

In conclusion I would recommend doing more measuring, and maybe reading a book or two about sound engineering before diving in again. Learn from my mistakes and optimise this design. It does sound amazing, but it might also sound better if I knew more.

About the Designer:
My name is John and I’m an industrial bread baker and packer. I have little to no experience in electronics and I’m just a general nerd who is into PC gaming and general tech. I’ve had over 5 years on and off experience in timber work projects and i’m not a newbie when it comes to tools and crafting in general.

Project Parts List:

Dayton Audio KAB-230 2x30W Class D Audio Amplifier Board with Bluetooth 4.0
Dayton Audio KAB-BE 18650 Battery Extension Board for Bluetooth Amplifier Boards
Dayton Audio RS100-4 4″ Reference Full-Range Driver 4 Ohm
Dayton Audio ND16FA-6 5/8″ Soft Dome Neodymium Tweeter
Penn-Elcom D0941K Blank Dish Black 3-1/2″ x 5-1/8″
Jantzen Audio 0.35mH 20 AWG Air Core Inductor Crossover Coil
Jantzen Audio 39uF 400V Crosscap Capacitor
ERSE 0.24mH 14 AWG Perfect Layer Inductor Crossover Coil
6.8uF 100V Electrolytic Non-Polarized Crossover Capacitor
Speaker Cabinet Port Tube 1″ ID x 4″ L Flared
Middle Atlantic GUARD Muffin Fan Grill Guard For 4-1/2″ – 4-5/8″ Fans
SPST Sub-Mini Toggle Switch
19 VDC 4.8A Switching Power Supply with 2.5 x 5.5mm Center Positive Plug
AS/NZS 3112 3-Pole Plug to C13 Polarized IEC 6 ft. Power Cord 18/3

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