W(MT)W 3 way Center speaker

W(MT)W 3D-Printed Center Channel Speaker

This is a 3-way, 3D-printed W(MT)W center channel speaker designed specifically for home theater use. Thanks to a low crossover point between the midwoofers and midrange, it avoids the common off-axis issues found in typical MTM center designs. This means you’ll get consistent, clear sound even when sitting off to the side—perfect for wide living rooms or group movie nights.

It features two Dayton TCP115-8 woofers, a DMA58-8 midrange, and a silk dome tweeter in a horizontally oriented MTM-style layout. The frequency response is flat from 110 Hz to 22 kHz, and with some AVR tuning, it's very usable down to 80–90 Hz. The F3 is at 103 Hz, which is more than adequate for a center channel speaker in a surround setup.

The enclosure is designed to be printed in large pieces and then cut down according to your printer's build size. You'll need to slice the model yourself to fit your printer, taking care to avoid cuts across screw or insert holes.

Parts List

Speaker Components:

• Dayton Audio TCP115-8 4" midwoofer x2
• Dayton Audio DMA58-8 2" midrange x1
• Dayton Audio ND25FN-4 silk dome tweeter (or others with custom mount) x1
• 3.3 ohm 10/20w resistor (for tweeter matching) x1
• Dayton Audio XO3W-375/3K 3-way crossover x1
• Materials:
• PLA filament (~1.5kg) – do not use PETG (epoxy doesn't adhere well)
• Sheet of MLV (like Vibrofiltr) – optional, helps reduce resonance
• Assorted speaker wire
• Blue Tak / Patafix / poster putty
• Strong two-component epoxy (plastic-compatible)
• Speaker foam or wool

Threaded Inserts:

• M3, 5mm length (OD 4.2mm) – 12 pcs
• M4, 6mm length (OD 6mm) – 30 pcs (buy extra, they're easy to lose)
  AliExpress Link

Speaker Terminals:

• 2 pcs
  AliExpress Link

Screws:

• M4 x 14 mm – 22 pcs (rear cover)
• M4 x 10 mm – 8 pcs (TCP115 drivers)
• M3 x 10 mm – 4 pcs (crossover)
• M3 x 8 mm – 8 pcs (DMA58 + tweeter)

Build Guide

Printing:

Start by printing all parts. The main box should ideally be printed with the front baffle facing down. Cut it in your slicer so it fits your printer. When cutting, avoid slicing through threaded insert holes or screw holes.

Slicing settings:

• Infill: 20–40% (use higher if skipping Vibrofiltr)
• Perimeters: 3 for strength and good grip for inserts
• Supports: Use tree supports for the midtone driver chamber overhangs
• Add mouse-ear brims on sharp corners to prevent lifting

Back cover should also be sliced to fit your printer. Do not cut the back cover in the same spot as the main box—this will cause air leaks. Use the same slicing settings as above.

The tweeter mount can be printed however you prefer. I used 100% infill to avoid any risk of vibration.

Assembly:

Gluing: Use 5-minute epoxy formulated for plastic. Dry fit and sand contact edges for a snug fit before gluing. You only get one shot at this, so take your time.

Pay close attention to:

• Front baffle flushness
• Rear case alignment
• Clean, filled epoxy joints

Install threaded inserts using a soldering iron set to 260°C. Be patient and keep them straight. Do this for all main case holes (except the 4 edge holes on the front baffle for magnets), and for the 4 shallow holes in the rear cover.

Speaker Prep:

• Solder leads to all speakers. Make sure the DMA58 wire fits through its back slit. Epoxy the tweeter to its mount, avoiding the dome. Get it flush for a proper seal.

Speaker Installation:

• Install TCP115 drivers first. Use a thin snake of putty around the mounting area. Keep the stock foam on the drivers for extra sealing. Screw in with M4x10, using just enough torque to compress the putty.
• Install DMA58, feeding the wire through the slit and sealing the hole with putty. No additional seal is needed as the driver includes foam.
• Install the tweeter with putty for sealing.

Vibrofiltr and Damping (Optional but recommended):

• Apply Vibrofiltr sheets to:
• Inside cabinet walls
• Back of midtone volume (not inside the sealed volume)

Add a small amount of speaker foam or wool inside the rear cover. Do not overfill.

Rear Cover and Crossover:

• Strip speaker terminals down to their copper parts. Screw them tightly into the rear cover until flush. It’s a tight fit by design to ensure sealing.
• Mount crossover with M3x10 screws. Connect inputs and outputs as labeled. Don’t forget the 3.3-ohm resistor in series with the tweeter.

Final Assembly:

• Flip the speaker onto its front. Use the TCP115 boxes to support it. Protect the tweeter dome.
• Make long snakes of putty and apply around the rear cover edge (not over screw holes). Use M4x14 screws to secure the back cover, tightening evenly like you would with an engine block for a uniform seal.
• Clean off any excess putty from the rear.

Done!

Enjoy your new center speaker. Clear vocals, great imaging, and a rock-solid DIY cabinet built to perform. If you remix it or come up with your own baffle/tweeter swap, be sure to share it! Step files are included, so remixing is invited! 

Also the OnShape project file is here! https://cad.onshape.com/documents/576987e43b6144f087372001/ get creative and play with it!!!