This Fix-It Guide on speaker repair tells how a speaker works, what often goes wrong, how to identify a speaker problem, and what parts and tools you will need to fix it. It then gives simple step-by-step instructions for how to disassemble a speaker, how to repair a damaged speaker cone, and how to obtain correct speaker polarity (phasing). Fortunately, speakers are relatively simple in design and can be fixed easily. This guide also refers to other Fix-It Guides for specific repairs.
How Does a Speaker Work?
Audio speakers for a home stereo or entire home entertainment system amplify the sound generated from another component of the system. The typical speaker is a collection of complementary parts. The typical enclosure (speaker case) has a 6- to 15-inch-diameter cone woofer for low frequencies, a 3- to 6-inch-diameter dome or cone mid-range driver (commonly called a speaker), and a small tweeter for high frequencies. Audio signals move along speaker cables to a terminal block at the back of the enclosure. Once inside, a crossover network divides incoming frequencies into the appropriate ranges, sending each to the correct driver. Drivers then convert this input into mechanical movement of the cone which, in turn, moves the air in a way that is detected by your ears as sound.
What Can Go Wrong with a Speaker?
Speakers are most likely to suffer from improper use. The enclosure can be damaged or come unglued. The speaker can blow an electrical or thermal fuse. Wiring can be faulty. The voice coil can be faulty, a speaker can be blown, a crossover network can be faulty, or a solder connection can be faulty. Cables and connections can be faulty; a driver cone can be damaged. Speakers may not be in phase. Level controls can be broken. All are repairable.
Many problems with speakers are actually oopses. “Oops” is what you say when you find out that the problem actually is a speaker button not pushed on the amplifier, a volume knob is too low, a wire has become disconnected, or something isn’t plugged in. Oops!
How Can I Identify a Speaker Problem?
- If the speaker does not produce any sound, check other components for proper connection and adjustment. Disassemble the enclosure (see below) to check the electrical or thermal fuse and replace or reset as needed.
- If no sound comes from all drivers in one speaker, check the fuse, test the speaker, and crossover network wiring and replace if necessary. Also test with another speaker and cable. If there is still no sound, the problem is with the receiver.
- If no sound comes from one driver, test the driver (see below). Also lightly press the cone with a finger. If the voice coil does not move in and out freely, replace the driver.
- If the sound is distorted or mushy, use your hand to flex the cable with a low-volume input. If sound varies, replace the cable and clean the connections. Also check polarity of the speakers (see below). Carefully press the cone in and out with your fingers to determine smooth action, and replace it if action is not smooth.
- If the speaker is noisy, check the voice coil. Use rubber cement or a repair kit to repair any small holes in the cone. If the driver is badly damaged, have it re-coned by a professional or replace the driver. You also can clean the volume control with an electronic contact cleaner.
- If sound is intermittent, check the speaker cable and connections, test the thermal fuse and check the voice coil.
Should you replace the driver or have it re-coned? The answer depends on the cost of a replacement and your budget. Common drivers for low-cost audio systems are relatively inexpensive to replace (so you can gamble and try to fix it yourself). Larger drivers for better audio equipment and musical instrument amplifiers are relatively expensive. Drivers for that classic Fender amp probably should go to a professional service person.
What Do I Need for Speaker Repair?
You can buy replacement speakers, speaker repair kits, foam, wire, and other parts and materials at electronic and audio stores. These are other things you may need:
- Rubber cement
- Kraft paper patch or repair kit
What Are the Steps to Speaker Repair?
Disassemble a speaker unit:
- Unplug the speaker cable. If the speaker is a powered unit, unplug it from the electrical receptacle (outlet).
- Remove the speaker enclosure’s front grille to access the drivers and the crossover network. Grilles are secured with snaps, Velcro, or screws.
- Unfasten the drivers, as needed. Drivers on a bass reflex speaker are screwed in from the front. Some speakers are sealed in position and may require a sharp knife to break the seal. If so, replace the seal with sealer from an electronics store when the repair is finished.
- Lift the driver from the enclosure to gain access to the wire connectors that attach the terminal block to the driver. Use pliers to carefully remove the wires from the rear of the driver or the terminal block, or both locations. Note that some internal wires are soldered rather than clipped.
- Remove the crossover network, as needed. Most are accessed from the front of the unit, though some are inside and are accessed once the main driver is removed.
- Find the unit’s fuse and test it with a multimeter.
- Use the multimeter to test resistance and continuity on the driver(s), crossover network, and/or the terminal block as needed. Most drivers will have their resistance indicated on the back side, such as 8 ohms.
- Replace components as needed and reassemble.
Repair a damaged speaker cone:
- Identify the location of any small holes on the cone.
- Apply rubber cement to the front and back side of any holes in the cone. If necessary, place a piece of thin kraft paper over the first layer of rubber cement to keep the cone from tearing.
If the cone is torn or has numerous large holes, have the driver re-coned or replace it.
Obtain correct speaker polarity (phasing):
- Check the audio output device (stereo receiver, CD player, etc.) to make sure the speaker wires are correctly attached. The red terminal is [+] (positive) and the black one is [-] (negative). Better quality speaker wire has a corresponding color code or some indication of polarity preference. If yours does not, attach the two wires in any manner, but make sure that the same wire that is [+] on the source is [+] on the back of the speaker enclosure.
- Connect the wires up to the speaker enclosure in the same manner: [+] wire to [+] terminal, [-] wire to [-] terminal. The result will be richer bass tones.
Want to make sure that the speaker wires are polarized correctly? Clip a wire to each speaker terminal, then touch the other end of each wire to a terminal on a AA or C household battery. The cone will move out when the two positive terminals are connected to each other.