Designing, Building, And Testing Your Own Speaker System With Projects PDF.pdf _HOT_
Building your own custom speakers has got to be one of the most rewarding, straightforward and cost-effective DIY activities I've come across. I'm absolutely shocked that it hasn't had a larger presence on Instructables and in the community...well, until now of course.Some speaker projects can be complete in a weekend, while others can go on for years. Budget speaker kits start around $100, while top-of-the-line kits and components can add up to several thousands of dollars. Regardless of how much you choose to spend on your speakers, you'll likely be building something that will sound as good as commercial product that off the shelf would cost as much as 10 times more.So, if you've got access to a table saw, a jig saw, a drill, some wood glue, clamps, and a place to make some sawdust, then you've got the opportunity to build your own custom speakers. This Instructable will cover the entire process, from sourcing components, to tips and tricks, to exotic and inspiring finishing options.The images below show just a few of the speakers that I've built over the last 10 years.
Designing, Building, and Testing Your Own Speaker System with Projects PDF.pdf
Before embarking on a DIY speaker building journey, take some time to familiarize yourself with the process (this Instructable should cover that), and also poke around sites that showcase DIY speaker builders work, designs, and the companies that distribute the best components in the U.S. There's a wide range of designs, driver options and technologies to learn about and choose from.
Once you've selected your drivers it's time to begin planning out the cabinet. Work with your component provider to choose a box design that best matches your specific components. If you're building a kit, a box design should have come along with your drivers and crossover plans. Box design can make a $5 driver sound like a speaker that costs $500 retail, but if it's not designed and built correctly, it can also make a $500 driver sound like it was ripped out of an old transistor radio. DIY speaker builders can't make their own drivers very easily, but we do build our own speaker cabinets, so that's where we tinker, innovate, build with care, and shine. As a result, it's the cabinet design and execution that we spend the most time on. Cabinet design decisions start at the basics, like the volume of the cabinet, whether it will be sealed or ported, how much bracing the cabinet needs, what thickness material it should be made out of and what height the tweeter should be mounted at so that it's in line with the listeners ears.From there, it progresses to more complex and acoustic decisions like rounding over the corners to reduce interference, building elaborate horn structures to amplify the sound, using exotic materials to further dampen resonant frequencies, line arrays to gain efficiency, mounting drivers at different distances from the listener to accommodate for the fact that high frequencies travel slightly faster than low frequencies, and eliminating parallel faces - the surfaces that create resonant frequencies, by building poly-faceted cabinets, or better, spheres, rather than the standard rectangular cabinet. That being said, the vast majority of DIY speaker builders start with a straightforward, rectangular cabinet design that even though lacks the bells and whistles, and highly engineered elements listed above, still sounds fantastic.An example of a MTM bookshelf speaker speaker design appears below from Zalytron.
I build all of my speakers from a type of fiber board called MEDEX. It's a LEED certified formaldehyde free material that's similar to MDF, but far heavier, denser, and moisture resistant. Many contractors use it as a building material in humid climates, and it's widely used to make counter tops. It's not stocked in every lumberyard, but it can be special ordered. If your local lumber yard can't find a source for it, or if you don't want to pay the higher price for it, MDF is the next building material of choice. Avoid plywood, hardwoods, OSB, strand board, and light density fiber boards if possible.The speaker cabinets should be as sonically dead as possible. That means heavy, thick-walled, and well constructed. Ideally the entire cabinet should be built out of 1.5" material. In reality, I've only done a handful of speakers that were that thick due to the cost and weight. The industry standard is a 1.5" front baffle, and then 3/4" for the rest of the cabinets. Zalytron builds their cabinets to these same specifications. Many other companies do not. Look closely to see what's included in your specific kit if your ordering one that has the cabinet included.Plan out your speakers on paper and create a cutting diagram based upon the raw 4' x 8' sheets. Head to the lumberyard and pick up as many sheets of MDF or MEDEX as you need for your projects.Transfer your cutting diagram onto the sheets themselves and then begin to break them down, making the biggest cuts first. Work the large sheets down into small manageable panels and cut things to their exact size. When cutting like-sized speaker panels make all of your same-sized-passes on the table saw at the same time, without moving the fence, to ensure that parallel panels will be exactly the same size.Once all of your panels are cut, check and then recheck your measurements. If the speaker cabinets are going to be square, they've got to start with perfectly cut panels, otherwise they just won't ever line up correctly.
As shown in the cabinet design in step 5, the basic speaker cabinet contains supports on the inside to further strengthen and sonically dampen the exterior walls. These supports are usually cut from scrap 3/4 material and are cut with a swiss cheese like pattern to allow air to pass through them so that they don't divide the cabinet and impede air flow inside.Internal support panels should be located in parts of the speaker that are closest to the woofers, and anywhere that the cabinet may need reinforcement, like the midpoint of the sides.The tower speakers have two internal supports, while the bookshelf speakers have only one. Trace a simple pattern of circles or squares onto the support panels and use a drill with a large drill bit to create a starter hole for your jig saw. Then, use the jig saw to connect the drill holes and trace the path of your cutout.The picture set below ends with the brace for the subwoofer, so it's a bit bigger and has a larger cutout for the larger subwoofer driver.
Like most professional kitchen cabinet makers, I use biscuit joints to hold my speaker cabinets together. They easily and perfectly align adjacent faces, are quick to cut and install, and are super strong. First, mark adjacent surfaces with a pattern or code of your choosing. I simply assemble the speaker panels into the correct formation and mark adjacent sides with an "a", "b", "c", or "circle", "square", "triangle" code and so on. I then give them a little tick mark crossing onto both sides where I'll alight the biscuit joiner to make the plunge, and draw a long line on the face that will get a groove cut into it, so that I don't get lost and cut into the wrong face. See the secondary photos below to see what I mean.With the faces all marked up, I clamp the boards down to the table and begin cutting slots with the biscuit joiner. I generally install two biscuits per joint on the speaker cabinets. This part is a bit tedious, because there are many joints and adjoining faces, but it's worth it when you go to glue because things will line up really well. I find messing around with screws while trying to glue and clamp the cabinets together is just a bit clumsy and certainly more difficult to square up.
With the sides, top and bottom of the cabinets drying, it's a good time to start work on the front and back panels. First time builders may choose to simplify this step and simply cut a large circle opening for the speaker driver to mount in. In that case, the speaker drivers' frame will rest on the surface of the speaker, protruding an 1/8" or so. For a truly professional look, however, you'll want to recess the drivers so that they mount flush with the front face. In either case, the first step is to cut out a circle that accommodates your driver. I use a plunge router fitted with a Jasper Circle Jig. This Jasper Jig allows be to cut a circle of just about any size up between 2" and 18". If you don't happen to have this handy router and circle jig set up, the old drawing a circle using a piece of string tied around a nail works pretty darn well too. Then, simply cut carefully along your line with a jig saw and you're in business.If you are using a router, use a 1/8" or 1/4" straight bit to cut out the circle so you end up removing as little material as possible. The wider the bit, the more material you have to eat through, the more dust you create, and the slower the process goes. Make multiple passes, incrementally plunging deeper and deeper through the front face.Once the circles are cut, it's time to tackle the optional recess.To do this you need to create a pattern template. Carefully trace, draw, plot, copy, CNC cut, or laser cut the outer pattern of your driver onto a thin piece of material creating a template. Technical drawings for speaker components can usually be found on the manufacturers or resellers website. Recreate a pattern in a drafting program of your choice from the drawings and produce the actual pattern piece. Remember, this step is totally optional!Once the patterns have been created, center and mount it into place on the front face. I'm using some simple wood screws in the photos below. Then, using a good router and a sharp straight bit fit with a pattern bushing collar on it, simply trace the pattern at the proper depth to create the recess.Elliot from Zalytron has been kind enough to use his vast library of patterns to route the driver recesses for me when they're too complex for me to generate on my own - so if you're sourcing components from him, see if he can help you out.