Testing A Speaker
How To Tell If It’s Any Good By Chuck T.
Lets start out by saying experts recommend using a speaker in your car with a plastic cone; not paper. A paper cone is more likely to warp when it adsorbs moisture.
A speaker works by having an electromagnet’s magnetic field work against the field of a permanent magnet. The speaker makes sound by feeding a variable current into a coil while a permanent magnet attempts to hold the coil still. The current contains the sound information and the coil is attached to the cone. So, the current will add or subtract the electromagnetic field rapidly enough for the cone to make sound.
Here are three tests that you can make on a car speaker. If it passes these tests, it probably is good.
TEST ONE: This is the most common defect occurring with speakers. Hold the speaker with your ear inside the cone. Insure it does not touch your ear. Push the cone in and out about a half inch and listen for a scraping sound. The cone is good if you hear nothing.
TEST TWO: Coil continuity test. You’ll need a multimeter or a D cell battery for this one, but the good thing is that speaker coils seldom loose continuity. Ohm out the two input wires attached to the cone. A good coil should read less than five ohms. If you don’t have a multimeter, you can use a D cell battery. Connect wires to the positive (smaller) end and another wire to the negative end. You can solder them if you wish. With the two wires, touch the two inputs to the wires going to the cone. The cone should move either in or out while making a static noise which means the coil is good.
TEST THREE: Cone damage, mostly visual. Look for signs of cone warp. The cone should be smooth and wrinkle free. If any defects are found or, if you are not sure, throw the speaker away.
I use Pyle speakers. They are made in China to American strict standards and they have not failed me yet.
