The project uses a Hypex subwoofer amplifier, a 10” subwoofer driver, and a pair of Genelec 8030 speakers that can only reach 55Hz of bass, making the speaker good for music sounds but lack a bit of depth with movies. The subwoofer driver made by Norwegian Seas is sponsored by Hifitalo.fi which includes the parts shown in the image below.
Since the subwoofers are not built in random boxes, the box needs to be designed. The plan can be made using a program called WinISD where the parameters of the subwoofer driver can be inputted and the different box designs that will work with the driver and amplifier can be simulated. To get started with the design, WinISD has help files since different drivers work best in different type of enclosures. A reflex enclosure was chosen using WinISD since the Seas used works in both sealed and bass reflex boxes.
A screenshot of the WinISD program is sampled below where the performance of the vented box is represented by the yellow line and for the half the size sealed box is the blue line. About 100dB SPL at 20Hz sound is produced by the vented design while the small sealed box reaches only about 92dB, showing the 8dB difference. The sound pressure level is represented by the vertical numbers on the left.
MDF board was used to build the box because it’s an easy material to work with and cheap. Two MDF layers were used to make the front wall of the sub and the box was made as dead as possible by having internal braces. A router is used to round the finished box from the edges, as shown below.
By altering the port length and diameter, the tuning of the ported box can be made. WinISD is used to calculate the optimal dimensions of each driver and box. The tuning can be made lower by making longer port and the unwanted noises can be minimized by making both ends of the port rounded. The piping can be seen from the image below.
The next image shows the MDF boards glued and screwed together and the sanded elastic filler is used to hide the embeddings of the screws. The amplifier will be located in a backpack.
For the finishing touches, leather is used to cover the box, as shown below. To make the back of the case more stealth, the high-level input from Hypex amplifier was removed. The acryl parts was fitted, glued, and screwed in place. Acoustic foam is used to fill the interior of the case. A small clearance has to be left around the bass port since polyester foam is so breathable.
The finished product is shown in the next images.