As a kid have you ever wondered seeing simple wooden box talking loudly or how come a radio speaks when nobody is inside? May be you haven’t but many of us did. And that was our first encounter with speaker – a simple conical looking device tucked inside the box does all the wonder. From basic to expensive, all speakers have 3 primary components. They are crossover, driver and speaker cabinet. Driver is generally a conic shaped component that converts electrical signal into sound wave.
Crossover divides the main electrical signal and distributes according to the frequency ranges among different speakers to enrich the blend of end sound. In absence of crossover, speaker would still work but sound would be dull. Cabinet houses driver and crossover. Besides the role of an enclosure, it also eliminates internal sound feedback coming out from the drivers’ back. If this interference is not cancelled, that would spoil end output of the speaker. A good speaker needs lot of labor that goes into designing a suitable combination of all those three. So, that won’t be a moderate job. But you can build a simple general purpose speaker.
Difficulty level: Moderate
Time required: It varies person to person
1. Medium density fiberboard or MDF for construction of cabinet
2. Two 5.25 inches 2-way type car-speakers
3. Two terminal cups for two speakers
4. Normal insulated wire
5. Wood screw and glue for fixing and joining
6. Drill, table saw and a jigsaw for making holes and cutting MDF
Estimated cost: N/A
1. First let us construct the speaker cabinets. Each cabinet has 6 sides so you have to cut 12 pieces of MDF. Front and back panel would of in size of 7x12 inches. Cut 4 such pieces.
2. Both the sides of the speakers would be 5x12 inches. You have to cut 4 of them, two for each.
3. Top and bottom sides would be of 5x5.5 inches. We need 4 of them.
4. Front side panel would hold the 5.25 inches speaker. So, you need an opening of equal size on front panel. Better draw a template on a card board of directly on the MDF and cut the piece accordingly.
5. Terminal cup would be attached with the backside panel. Draw a template similarly and cut two back panels in the same way.
6. Now you need to join front panel with all the side panels. Front side would overlap side panels. First screw the panels properly and then apply enough glue to secure the joints.
7. Cut an at least 7 inch long piece of wire. You have to connect one end of the wire with terminal cup and other side with the end tab of car-speaker.
8. Put the car-speaker inside the cabinet through the front opening. Fix the speaker with front panel with screw properly.
9. Terminal cup needs to be wired with the speaker, as said earlier, and fixed with the back panel. Use screw for fixing the cups.
Now, your basic all purpose speakers are complete. Connect any audio device and test how they are speaking.
Frequently asked questions
Q. what can I do to stop interference of internal noise or sound feedback?
A. Generally, sound absorbing materials are used for this purpose. But to talk on them we need another lengthy discussion.
Q. Any other speaker size I can work with?
A. Yes, you can do so. But for that you have to change cabinet size. Oversized or undersized cabinet won’t produce good final output.
Q. Why we have not used crossover?
A. Crossover is important and you need more than moderate skill to handle them. And that’s the reason it is beyond our scope. Absence of crossover does not stop you from listening audio produced by driver of the speaker. It just blends them well and enriches the final output.
Q. Can any other material like wood be used for cabinet construction?
A. Of course you can do so. But remember, extremely rigid cabinet body would worsen interference by sound generated by speaker internally.
1. To make your speakers good looking you can paint them with normal oil paints. Try giving them a cool look.
2. Medium density fiberboard or MDF are stronger than plywood and you could join them with normal woodscrew and glue. For a normal size speaker cabinet you would require 14 by 8 foot MDF with 0.75 or 3/4th inch width.
3. 2 way type speakers have 2 plugging points, balloon, binding post or simply plug-in type, for connecting wires carrying audio signals from any audio device.
Things to watch out for
1. Be extra cautious when using instruments like drill and table saw. They are capable of hurting the user if not handled properly.
2. MDF is made of grainy saw particles. Cutting MDF creates lot of dust and it won’t be good to breathe them in. So, use respirator for safety.
3. MDF emits volatile organic compounds or VOC. These are harmful to health. To avoid this, paint open parts of the panels. However, emission lasts till only couple of months after manufacture.