The design of a subwoofer

If you want to build a loudspeaker yourself then a subwoofer is the best type of speaker to start off with. It's quite easy to build compared to a multiple driver speaker.

1. What do you require

First you should consider what you require from a subwoofer. This will help you in establishing which subwoofer type suits your taste most:
- maximum precision -> closed cabinet, horn
- low bass -> bass reflex, band pass or transmission line
- high efficiency -> horn systems
Choose the loudspeaker type that's suits you most. If you are not quite sure we recommend to build a bass reflex subwoofer or contact us; then we'll find out together which subwoofer type suits you most. Below we'll show you how design and build a bass reflex subwoofer (or closed cabinet).

2. Selection of drivers

After the type of subwoofer has been chosen the bass driver has to be selected accordingly. To do this it's best to use one of the software programmes where the Thiele and Small parameters of possible contenders are entered:
- simple calculator for closed cabinet subwoofer
- simple calculator for bass reflex subwoofer
- LspCAD Lite (also for band pass)

After you have found a driver that suits your subwoofer, and the cabinet size and length of the bass reflex tube has been established you can start designing the cabinet (remember to add a few litres for a possible subwoofer module).

Please contact us should have problems in finding a suitable driver.

3. Cabinet design

To quickly calculate the dimensions of the cabinet and the size of the required panels the following calculator is available.

Volume Calculator

After the cabinet has been designed you still need to choose the subwoofer module or amplifier module for car audio applications.

The cabinet of a car subwoofer should be 10 % smaller than the calculated value.

4. Building the cabinet

Now it's time to build the cabinet:
We recommend to buy ready cut panels at a hardware store.
.... Building the cabinet ....


- The heavier the wood, the better the sound (the cabinet shouldn't resonate).

- If the subwoofer is quite large, additional bracing panels prevent the opposite panels from resonating. Therefore, all panels that are larger than 40 x 40 cm should be braced internally. Especially effective are bracing panels that are joined in the centre of two panels or those that are joining three panels. All bracing panels should, however, be only 1/4 of the cross-section of the cabinet to ensure air circulation.