Design Example

  • Dayton Audio DC200-8

    The DC200-8 is an 8-inch woofer manufacturer by Dayton Audio and can be easily purchased online. It's a very commonly used woofer since it's rather cheap for it's decent performance. It offers a non-pressed treated paper cone, ASV voice coil, vented pole piece, rubber surround, and a coated cloth dust cap. The specification sheet boasts a frequency response down to 29 Hz.

  • First steps

    We'll start by entering in the Thiele/Small parameters of the woofer into WinISD. If you are unsure how to do this correctly, click the button below:

    After doing so, we'll create a new project, select the Dayton Audio DC200-8 as our driver, choose "1" as our number of drivers and "Normal" for placement, select "Closed", and then choose a "0.707 Max flat amplitude response" alignment.

    Something interesting to note is that when we get to the "Box type" section of making a new enclosure project, the EBP (Fs / Qes) of the driver is calculated. This stands for the Efficiency Bandwidth Product, and is used to highlight the trade-off between efficiency and bandwidth of a driver. A good way to think of it is that the EBP gives the designer an idea of how well a woofer can be "controlled" without aid from the enclosure. A woofer with a stiff suspension and a high sensitivity will have a high EBP and therefore work best in a vented enclosure. The EBP of this driver is shown as 62.1, which is in the middle of the Vented and Closed recommendations. This is one of the reasons I chose this driver as our example - it would work well in both sealed and vented enclosures.

    The alignment choice of the driver is the default because it typically works best for quick designs. This fixes the Qts of the enclosure which typically determines the volume. An enclosure with a Qts higher than 0.707 will typically result in higher SPL, but will be more peaky, have less transient response, and have greater group delay. An enclosure with a Qts larger than 0.707 will have better sound quality but will be harder to drive (require more power), and will require a larger volume.

  • Default Design

    The default design is shown here on the left. As you can see, the low-end of 29 Hz boasted about in the specification sheet is not exactly accurate here - we'll see if it's true for a sealed enclosure instead later. This enclosure has a 3dB point at 53 Hz. We'll see how small we can shrink the enclosure while still preserving sound quality and low-end response.