Build guide
Printing, assembly, wiring and setup.
What happens after checkout
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Step 1
Get your files
Download your plans and guides.
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Step 2
Print and build
Source the parts, print the enclosure and assemble it.
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Step 3
Connect and listen
Hook it up to your subwoofer amp and enjoy.
$39.00 AUDOne-time purchase
Full guides included
Print, build, wiring and setup
Compact 6.5-inch sub
Made for desktop and small-room systems
Self-source build
Source the parts yourself and build anywhere
Build support
Help by email or Discord
The project
What you’re building
Subsonic Mk3 is a compact passive 6.5-inch subwoofer designed for desktop, under-desk and small-room systems.
- Build type
- Passive 6.5-inch ported subwoofer
- Best for
- Desktop, under-desk and small-room systems
- Skill level
- Easy
- Output
- One complete passive subwoofer
Print the enclosure and baffle, install the binding posts and driver, then assemble with screws and EVA gasket tape. No glue or woodworking required.
Before you build
What the build involves
A beginner-friendly project with straightforward printing, assembly and basic soldering.
Skill level
Easy
Suitable for beginners who are comfortable screwing an enclosure together
Printer fit
220 × 250 × 250 mm minimum
Fits in most modern printers
Print time
Around 2–3 days
The main enclosure may take 48 hours or more; total time depends on your printer and slicer settings
Build time
One afternoon for most builders, excluding print time
Covers enclosure preparation, wiring, baffle assembly, driver installation and fitting the feet
Want to see the process first? Preview the build guide.
Fit check
Is this the right project for you?
Check the design requirements and source the listed components before you start.
Best for
- Desktop and small-room systems
- First-time speaker builders
- Anyone happy to source their own parts
Not the best fit for
- Anyone wanting a powered, plug-and-play subwoofer
Soldering
Basic soldering required
You solder the speaker wire to the binding-post tabs and to the woofer terminals.
Finishing
Optional
No cosmetic finishing is required.
The digital plan
What you get / what you source
A one-time digital purchase. You source the physical parts separately.
Digital delivery
Included with the plan
Everything needed to print and assemble the Subsonic Mk3, except the physical parts.
Printable files
The enclosure, front baffle and useful build tools.
STEP-BY-STEP GUIDES
Clear instructions for sourcing, printing, assembly and setup.
Physical parts not included
You’ll source
Check the sourcing guide for the correct parts and quantities.
THE PHYSICAL PARTS
A short list of readily available components including a 6.5-inch woofer, binding posts and speaker wire.
Printing and assembly
PLA filament, basic hardware, gasket tape and common hand tools.
ALL EXACT PARTS, QUANTITIES AND LINKS ARE LISTED IN THE SOURCING GUIDE.
Build preview
How the project comes together
Print the parts, install the hardware, fit the woofer and connect it to your amp.
Step 1
Print the parts
Use the included files and print notes.
Step 2
Prep the enclosure
Remove supports and fit the gasket tape.
Step 3
Install the parts
Fit the binding posts, baffle and woofer.
Step 4
Finish the build
Add the feet and check everything is sealed.
Step 5
Connect and listen
Connect to your subwoofer amp and set it up.
SETTING IT UP
A simple 2.1 system
Subsonic Mk3 is designed to sit alongside a pair of speakers and a 2.1 amplifier, adding dedicated low bass to the system.
Typical setup
Speakers → main outputs
Subsonic Mk3 → passive subwoofer output
Documentation
See the project before you buy
Preview the guides and specs before you commit.
Build guide Preview the guide. Open the PDF for the full document. Preview PDF
Sourcing guide
Parts, hardware and materials you’ll need.
Spec sheet
Dimensions, specifications and measurements.
Design
Designed for bass. Designed to be built.
The Subsonic Mk3 is built around the Peerless SLS 6.5-inch woofer, with the enclosure, port and removable baffle designed as one system. The result is a compact subwoofer that is practical to print, easy to assemble and easy to open up again later.
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1
Built around the Peerless SLS 6.5-inch woofer
The cabinet volume, port tuning, baffle and mounting are designed specifically around the Peerless SLS driver rather than adapting a generic enclosure around it.
2
Bottom-firing bass-reflex port
The Mk3 uses a tuned bottom-firing port to extend the low end while keeping the front of the cabinet clean and the overall footprint compact.
3
Hidden binding posts
The speaker connections are tucked underneath the cabinet, keeping the wiring out of sight once the sub is in place.
4
Screw-together construction
The front baffle seals against gasket tape and bolts to the enclosure, so there are no permanent cabinet glue joints. It is simple to assemble, and just as easy to reopen for servicing or modification.
MK2 VS MK3
What changed in Subsonic Mk3?
Mk3 keeps the same compact concept, but is now a passive subwoofer designed to pair with an external amp, with deeper bass, more output and a simpler build.
Amplification
Mk2Built-in amp
Mk3Passive / external amp
Low-frequency extension
Mk2Original tuning
Mk3Deeper extension
Maximum output
Mk2Original design
Mk3Substantially higher output
Frequency response
Deeper bass extension
Mk3 maintains more output through the lowest frequencies, giving it noticeably stronger low-bass extension than Mk2.
Open graph
CTA-2010B maximum output
More clean output
Mk3 delivers a substantial increase in maximum clean bass output across the operating range.
Open graph
Technical specifications
Core build and cabinet requirements for the Subsonic Mk3.
Key specs
- Type
- Passive 6.5-inch ported subwoofer
- Printer fit
- Minimum W 220 × D 250 × H 250 mm
- Filament
- Approximately 2.3 kg PLA per subwoofer
- Print time
- Around 2–3 days depending on printer speed; the main enclosure alone may take 48 hours or more
- Amplifier
- External amplifier with a suitable passive subwoofer output
- Impedance
- 4 Ω
Speaker and electrical details
- Type
- Passive 6.5-inch ported subwoofer
- Amplifier
- External amplifier with a suitable passive subwoofer output
- Nominal impedance
- 4 Ω
Cabinet and print details
- Dimensions (H × W × D)
- 300 × 249 × 219 mm, including feet
- Printer fit
- Minimum W 220 × D 250 × H 250 mm
- Filament required
- Approximately 2.3 kg PLA per subwoofer
- Print time
- Around 2–3 days depending on printer speed; the main enclosure alone may take 48 hours or more
Explore this speaker project
These details describe the speaker you will build. This purchase includes digital files; you source all physical parts.
Subsonic Mk3 digital plans let you build a compact passive 6.5-inch subwoofer for desktop and small-room systems. Print the enclosure, source the listed physical parts and assemble it using the included build and sourcing guides. An external subwoofer or suitable 2.1 amplifier is required. Physical parts are not included.
Support
Help with your build
Step-by-step documentation, sourcing help and support if you get stuck.
- Step-by-step Build Guide
- Parts and sourcing guidance
- Troubleshooting for common build issues
- Email + Discord support
Questions
Before you start printing
Answers to common questions about this project.
Question Are physical parts included?
No. This is a digital plan. You source the physical components separately.
Question How do I receive the files?
Your digital files are emailed after checkout.
Question Where can I find the parts list?
Read the sourcing guide for the components and equipment required.
Question Is this suitable for a first speaker build?
Yes. The build is rated Easy and mostly involves straightforward printed-part assembly with a few basic solder joints.
Question Do I need an amplifier?
Yes. Subsonic Mk3 is passive and must be connected to a suitable external amplifier or passive subwoofer channel.
Question Do I need woodworking tools?
No. The enclosure is 3D printed and assembled using common hand tools.
Ready when you are
Ready to build Subsonic Mk3?
Print it. Build it. Make it yours.
Turn a roll of filament and a handful of parts into a compact passive subwoofer for your desktop or small-room system.
Get the digital plans
Digital files emailed after checkout. Physical parts are not included.