My first speaker build was for a friend. He wanted to be a DJ, I wanted to build speakers. We decided from the start to go big: 2000 Watts total power handling.
Perhaps it was a bit much for my first build, and more than he was anticipating for his uses, but it was the goal, and we were going to succeed.
The first part of the design was driver selection, choosing the actual moving parts. It took me weeks of reading, pouring through countless articles on speaker design and sound quality. I was determined to do this build right. After selecting the best drivers for the price point, the fun part began.
4 Inch Mid Range Speaker
(I would add a picture of the actual build here, but after going through the pictures from those weeks, I realize how poorly I documented the job. If I can find pictures down the road I’ll add them.)
The optimal total volume was 850 liters, after playing with some shapes we decided to go with the dimensions of 5ftx3ftx2ft, these speakers were huge. In my reading I discovered one of the best materials to build speakers out of, because of the sound characteristics, is ‘MDF’, or Medium Density Fiberboard. The layout was done, it was time for assembly.
The first step after cutting out the initial rectangles (the sides) was cutting the speaker holes in the “front” piece if wood. At the time I didn’t own a router to make perfect circle cuts, so I had to cut by hand. In order to cut an accurate hole, I first had to draw the circles on the wood. I ended up using charcoal on a sample speaker of the same size, to press the circle outline (of the felt) onto the wood. I then proceed to cut out the holes with a jig-saw.
The second most important quality in a set of speakers, after the sound, is the look and style of them. I knew the speakers would sound good, I had designed for that. What I wasn’t planning for, was making them look good too. I am by no means a graphical artist, nor do I have extensive experience working with fabric. This step caused me the most grief, I had no idea how to make this box look good. After many hours of fighting with the material, I decided to call in a favor. I had my artistic friend help cover the boxes with speaker-felt. The fronts were painted with high gloss paint, eventually to be covered with grill-cloth. The most stressful part of the build was now over, I could sleep well again. For my first artistic endeavor, it didn’t turn out bad at all, and I learned a great deal about the value of aesthetics, even if it took a little help.
12 Inch Woofers
(Same deal as before. Anyway picture two 12″ speakers topped by 6 4″ mid-range speakers, and 2 1″ super tweeters. Now do that twice.)
The next step, after seating the speakers in the holes, was wiring. Because of the amplifier the to-be-DJ already owned, I wired for a four ohm load overall. After installing the crossover (the circuitry that splits the highs and the lows of the music), and sealing the box, it was time for testing.
There are a few schools of thought on “burning in” speakers, or, playing low frequency tones with them, to loosen the elements. My view is that the process can’t hurt, and the tones make great test tones anyway. We carted the speakers outside, and hooked them up to the amp. They preformed beautifully. The first test, a song the DJ mixed(which he insisted was the first thing that played through the set), gave measured SPL levels of around 145dB at one meter, slightly softer than a jet engine at 30 m. After some tests for frequency response, I discovered the curve I was expecting did not exactly match the results I measured, I achieved flat response within +- 6 db (variance of the volume given a constant input power). Too large a range for future builds, but not bad at all for DJ use.
The entire build took 2 weeks, not including shipping time. Since my first build in March 2009, to the time of this post, I have designed and built five other speakers, each better than the last. I analyze the flaws in my designs, and attempt to fix them on the next build. I am ultimately striving for a perfectly flat response, in the minimal space, while still keeping aesthetics in mind.
Perhaps it was a bit much for my first build, and more than he was anticipating for his uses, but it was the goal, and we were going to succeed.
