Introduction: Transmission Line 6'' Loudspeaker With Responce From 30hz (-3db).

About: I like to design, produce and market acoustic systems and other stuff.

Tools and parts You need:



drill for 2mm (optional, for better screw placement).


Wax for furniture


wood glue (PVA i use).

3.5mm * ~15mm screws for wood.


Speakerhead, Wire terminal ant the inside wires.

For this plan, you need this speakerheads: (PDF attached).

Clamps for glueing plywood, minimum 2 by 250mm, better up to 6+ by 500mm.

1) Find a good project of loudspeaker.

(It shoul use parts that you can buy.)

(my plan is attached).

I project it myself. It is a transmission line type with 6" fullrange speakerhead.

Yoo need parts made of 12mm plywood, size in mm:

1x Face 200*926

1x Back 176*924

5x bulkhead 176*296

2x Top/Bottom 176*450

8x Turn 176*82 (ideally - trapezoid shape, but oke to make from thin plywood (4mm) )

You can get this in plywood trader, many of them can saw it for you by specified rectangular shapes.


Step 1: Glue

When You get all plywood parts, you just glue them to form a cabinet.

(before than, You may cut the holes for speakerhead , transmission line and wire terminal with a jigsaw, but i do this at assembled cabinet, see next step).

Use back as base of assembly.

First You glue back to the side. Make it feet good while glue not fastened. Use clamps to press parts firmly to each other for the better glueing.

Next glue top and bottom to side and back.

Next turn your box face side top and glue the face. Watch it to glue precisionly.

Then glue 2 bulks to the back and 3 to face, dividing it for 5 even parts. as shown on plan.

Next glue 8 turns by 45, as shown on plan.

And finaly, second side.

Step 2: Cut the Holes

Cut the holes for speakerhead, transmission line and wore terminal.

Terminal hole position is not critical, just circa the place on plan.

Step 3: Cabinet Finishing.

I use water based staining and furniture wax.

Before apply stain, you shound sandpaper the cabinet with grinder.

Next put 2 layers of stain, make it dry after each layer of stain.

I add some propanol to the stain, for it better laying to plywood. (optional, recomended).

Wood fibre can stand after stain, so after 2 layers of stain, better to sandpaper it another time slightly,

Then add final layer of stain.

Let it dry.

Then place use wax. I use cotton glove to put and spread the wax.

Wax dries some hours (see wax instruction).

Finaly, use soft plastic brush to polish the wax.

Cabinet finishing done.

Step 4: Mounting Speakerhead, Wire Terminal and Wiring.

Cut 700mm of about 2 square mm double wire, solder it to terminal.


Optional recommended:

Baffle step compensation.

Add a parallel cirquit of 2mH and 4 Ohm|5W series to speaker.

I use handmade coil of ferrite core 10mm diameter 100mm lenght with declared magnetic conductance 2000u, coiled with a 1mm copper coating isolated wire, six layers.


Mount terminal to the hole with screws.

Other end of wire, goes trough a speaker hole out.

Solder it to speaker, so speaker + match terminal +.

Now mount the speaker to the speaker hole.