I have always loved sound. I have played in several bands over a variety of genres. That combined with my background as an electronics engineer might be the reason why I have always had a weak spot for DYO loudspeakers. The last boxes I built some years ago were a set of pretty powerful vented 3-way speakers. Unfortunately large black boxes with oversized devices aren't part of the whole "fung shuy" thing, so to get them in our living room, I had to increase the WAF a great deal. That means they had to be a tad more discreet, compact, painted plain white and so on. Starring in frequencial order:
|RCF L12R300||12" woofer with 300WRMS power handling.|
|Zomax 2030||Mid-range compression driver (3" coil) with 75WRMS power handling mounted on a die cast iron horn.|
|Zomax 1205S||Slot tweeter|
First I had to choose a box design. The woofer's TS-parameters clearly indicate that it's best suited for a vented box. But having a 12" object on the front isn't at all discreet. An alternative is to use a serial bandpass design commonly used in subwoofers, where the speaker is mounted inside the box, and reflex ports are on the front and parallel with the speaker. Acoustically it's a much more complicated design than a closed or basic vented box design, so it's a fun challenge and I like the advantages in the physical design. Using loudspeaker box design software I modeled and tweaked the parameters until I got the dimensions and acoustics I wanted, i.e. a box with a frequency response from <50 Hz to 500 Hz and dimensions about 0.3x0.3x0.3 meter (about 1 ft^3). I guess that is the most compact speaker built with devices like this. The box is built in 12mm (½") MDF. It have two 100x35x12mm (4x1½x½") reflex ports on the front and four ø40x500mm (1½x4") tubes parallel with the woofer. I measured the devices and modeled the design in Google Sketch-Up. This allowed me to position the devices real close in 3D in the box and to get the visual design that I liked. It would have been impossible for me to build the speaker without the 3D model.