Why Do Car Speakers Cut Out at High Volume and How To Fix It?


When you are enjoying your music at high volume, you don’t want your car speakers to cut out.

There are many reasons why your speakers may cut out when you turn up the volume. Fortunately, there are many solutions to your speaker’s problem.  

The most often reason for speakers to cut out at a high volume is either issue with an amplifier or a problem with the crossover settings. Also, speakers that are not designed to handle a high volume can cut out often when overpowered.

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Once you know where the trouble lies, you should be able to fix it.

Tip: If speakers in your car cut out and your car audio system has been installed correctly, the issue can be in your car’s electrical system. The best way to find where is the problem is to test installation.

My favorite tester that works excellent and can measure all electric parameters is the Crenova 890Z Digital Multimeter. It will help you to analyze potential problems which may arise with your car audio system. 

In this article, I will show you how to troubleshoot your system and stop your speakers from cutting out during loud listening. I will also briefly explain terms like:

  • Amperes
  • Capacitors
  • Clipping
  • Gain
  • Grounding
  • Ohms
  • Watts
  • Voltage

How to Fix Speakers Cutting Out at High Volume?

When you start hearing that your speakers make strange noises or cut out fractions of your favorite tunes, there are several steps you need to take and to diagnose the source of the problem:

Check Your Amplifier

Today’s car amplifiers include a protection circuit that shuts the amplifier down when driven beyond its limits. If your system is cutting out at high volumes, something is causing your amplifier to engage its protection circuit.  

Check Your Gain Knob

Your amplifier takes the audio signal supplied by the radio or receiver and boosts it. A typical audio signal averages around 0.5 to 2 volts. An amplifier turns 0.5 volts into 20 volts or more, then sends it to the speakers to produce music.

The “gain” knob on your amplifier is not a volume control knob. When you adjust your gain knob, you will hear the volume increase or decrease. The gain knob does not change the volume, but rather, it adjusts the incoming signal from the amplifier.  

The volume controls on your radio or receiver adjust the outgoing signal. Turn it down, and the audio signal strength decreases, but if you turn it up, that signal gets stronger. An amplifier will amplify the weaker or stronger signals by the same amount.   

If your gain is set high, your amplifier will amplify your signal as much as it can. If you listen to your music at a low volume setting, an overly high gain may not matter, but if you turn your receiver’s volume up, your amplifier may run into problems.

Think of the receiver’s signal as a wave with peaks and troughs. When you drive your amplifier past its power limits, the rounded heights are flattened out or clipped. A clipped signal sounds distorted and harsh, or it can seriously damage your audio equipment.

When clipping, an amplifier produces more power than it can handle, which can damage output transistors. Clipping also causes a speaker’s voice coil to become hot. If the clipped signal is too strong, it can melt the voice coil or even cause the speaker cone to catch fire. The amplifier’s protection circuit cuts the signal before it destroys your equipment.  

If your speakers are cutting out, you need to check your amplifier’s gain. Set it at the point where your music gets loud when your volume is at about 3/4 of maximum, which will give your amplifier the headroom it needs to handle musical peaks without being overtaxed.

Check the Heat

Cars get hot on a warm summer day, and while air conditioning may make things easier for passengers, it does little to cool the trunk. Most car audio installers, and nearly all subwoofer installers, mount the amplifiers in the trunk. 

If your amplifier sits in your trunk, it might be hot even before you turn up your favorite music because of the lack of ventilation. And if you are playing loud music, your amplifier may get warm enough to trip the protection circuits and shut down.   

Other installers place the amplifier under a car seat. While this keeps your amp in an air-conditioned space, it comes with its problems. If your amplifier fits too snugly, it may not get the ventilation it needs for cooling.  

If your speakers are cutting out on a hot day, check to see if your amplifier is getting adequate ventilation. Amplifiers work best if screwed onto the back of the rear seats or on the subwoofer enclosure box.

Make sure there are no obstructions blocking airflow. If carpeting or trash covers your amplifier, a trunk cleanout will help it receive the necessary ventilation. You may also find that a cooling fan will keep your amplifier from overheating. 

This Stinger SGJ78 8.25-Inch Cross-Flow Fan will blow hot air away from your amplifier and lower its operating temperature.  

Make sure your amplifier is mounted correctly. If your amp is upside down, heat from the heat sink will radiate up toward your amplifier’s electronic components instead of dissipating into your trunk’s open space.  

Check Your Grounding Wire

Like all electrical devices, your amplifier operates on a circuit. Electricity travels from the battery to your amplifier, and as your volume increases, the amplifier requires more power. But it can only get that current if the circuit is properly grounded

Good car audio performance requires a well-connected ground wire. Buck Pomerantz of Crutchfield Audio says, “Improper or loose grounding is the #1 cause of amplifier problems”, and I have to agree with this statement 100%. 

A loose or undersized ground wire can impede the flow of current like a kinked hose interferes with water pressure.  

After the electrical current passes through your speakers, it needs to go somewhere. The ground connection on your wall socket connects to an actual wire which terminates in the ground outside your home. The earth absorbs the current and allows more electricity to flow through your amplifier.   

Your amplifier’s ground wire may provide enough flow to power your speakers at modest levels. But when you crank up the volume, the ground may be unable to keep up with the amplifier’s demands, and it cannot send enough electricity to the chassis where it can dissipate. When this happens, the voltage drops.  

Your car’s electrical system cannot provide more power than the grounding wire can handle, but the amplifier continues to demand power. 

If the disparity between electrical supply and demand persists, it may damage your amplifier, battery, and alternator. The amplifier’s protection circuit shuts down the system to avert this sad and costly fate.  

Here are the ways to resolve grounding problems that cause your speakers to cut out:

  • Make sure your ground wire is the same gauge as the wire connecting your amplifier to the battery.  
  • Scrape away any corrosion or dirt that might interfere with current flow.  
  • Use a lock washer, star washer, or anything else that will ensure a tight, clean, and electronically conductive connection. 
  • Check to ensure that your ground connection is solid, and your ground wire is secured tightly to clean, bare, and rust-free metal. 

If you want to make sure your amplifier is grounded correctly, you can check the connection with a digital multimeter. To do this, you need a multimeter and a length of wire that reaches from your ground location to the negative terminal on your car’s battery. Then do the following:

  1. Set your multimeter to measure ohms.
  2. Touch one multimeter lead to the ground location.
  3. Touch the other to the wire attached to the battery.

If you get a reading below 0.5 ohms, you have a good ground connection you can seal with silicone caulk to prevent future corrosion.  

This video from Car Audio 101 explains more about grounding a car amplifier:

Insufficient Power

Cut-outs can also happen when your system demands more power than your automobile’s electrical system can provide. If you notice decreased bass performance and flickering lights when you turn up the volume, your subwoofer might be sucking up more current than your alternator can provide.

Steps to check your alternator:

  1. Set your multimeter to test voltage.  
  2. Attach the meter to your car battery with the engine off.  
  3. If it reads less than 12.5 volts, charge the battery until you get a reading between 12.5 and 12.8 volts. 
  4. Start the engine and check the battery voltage with lights and accessories off. It should read between 13.8 and 15.3 volts.

This Crenova 890Z Digital Multimeter will help you to analyze these and other electrical problems that may arise with your car audio system. 

If your alternator is good but still struggles to provide your system with enough power, you have several options.

Get a More Powerful Alternator

Your car’s stock alternator can meet your car’s stock electrical needs. A high wattage amplifier may demand more current than the 65-100 amps most alternators can produce.  

Amps are watts divided by volts. A Polk Audio Car Amplifier which powers your fronts, rears, and subwoofer can draw 75 amps at full power. Even if your factory alternator can provide that voltage, it gives you little headroom for your car’s other electronic needs. 

A high-output alternator provides between 140 and 225 amps, which will let you enjoy your music at any volume while leaving plenty of amperage for lights, windshield wipers, and power steering. 

Install a Second Battery

If you listen to music at high volumes for extended periods, your car audio system may benefit from a dedicated 12-volt battery. A second battery will give you more reserve power for lengthy listening sessions when your vehicle is not running.  

For most listeners, a second battery is unnecessary. If you go this route, you should first upgrade your alternator, which charges the battery while your car runs. A second battery adds another amperage-sucking burden.

Add a Power Capacitor

Capacitors store electrical charge and release it when extra power is needed. 

A power cap will cost less than a new alternator or a second battery and be much easier to install, and will take some of the load off your car’s electrical system when the bass gets heavy.

Capacitors work best when dealing with occasional peaks and give you the freedom to turn your music up without worrying a big bass note will knock out your amplifier.

This Power Acoustik PCX-30F Farad Capacitor will help you avoid overtaxing your alternator during crescendos.

Check Your Speakers

If your amplifier is working, your problem likely lies with your speakers. Several issues can cause your speakers to cut out when you play them at high volume.

Low Ohms

An ohm is a unit of resistance. 

Imagine your speakers as a series of pipes. Wider pipes can handle a greater flow than thinner ones. Now imagine your amplifier as a pump that pushes water through those pipes until they are filled. 

Remember, however, that the amplifier must work harder to fill the wider line than the smaller pipes. Filling a sewer pipe requires more pumping power than filling a garden hose.  

Here are the different measures of electricity that we use for our speakers:

  • We measure the current going through our speakers in amperes or amps. (Not to be confused with the amps in our stereo system.
  • We measure the resistance which our speakers present to that current in ohms.  
  • We measure the pressure of that current in volts.
  • We measure the power of that current in watts.

You might think that your amplifier would find it easier to power a speaker with lower ohms since it offers less resistance. But things are a bit more complicated than that.  

Inside your car amplifier are two coils of wire wrapped around a magnetized iron core. After MOSFETs (transistor switches) transform your battery’s DC into alternating current (AC), the transformer steps up the voltage, but not the current.  

If you just installed rear speakers in your car in addition to front ones and connected them into your two-channel head unit with your front speakers, you have not increased the resistance but instead decreased it.  

Your head unit may have handled the 4-ohm load from your front speakers just fine. But if you connect two 4 ohm speakers to one terminal, your head unit now sees a 2-ohm load.

To send 100 watts into 4 ohms requires five amperes of current at 20 volts. Sending 100 watts into 2 ohms requires only 14.14 volts, but 7.1 amperes.  

Suppose your new subwoofer box has two 400 watts 2-ohm speakers. If the builder wired those two drivers in parallel, they would present a 1-ohm load to the amplifier. Sending 400 watts into 1 ohm will draw 20 amperes of current instead of the 14.14 amps for a comparable 2-ohm load.  

Most car amplifiers can handle a 2-ohm load. A 1-ohm load will challenge all but the beefiest amplifiers, so if you play your system at modest volumes, your amplifier will probably be able to keep up with the demand.

But if you have dual subwoofers, you probably don’t want to play them quietly. And when you demand too much current, your amplifier will shut down.

Check the ohm ratings on your speakers before you wire them together. If they fall below what your amp can comfortably handle, consider wiring them in series rather than parallel.  

The difference between parallel and series wiring are as follow:

  • Parallel Wiring-connects speaker A’s positive and negative terminals to the amplifier. Speaker B is wired to the positive and negative terminals of speaker A.
  • Series Wiring-connects speaker A’s positive terminal to the amplifier. The negative terminal of speaker A connects to speaker B’s positive terminal. The negative terminal of speaker B is connected to the amplifier’s negative terminal.  

Parallel wiring increases the ohm rating, while series wiring decreases it. Connecting your dual 2-ohm subwoofers in series presents an easy 4-ohm load to your amp. 

Here is a handy table you can use to calculate Amperes, Ohms, Watts, and Volts:

Amperes

Watts ÷ Volts

Ohms

Amps ÷ Volts

Watts

Amps × Volts

Volts

Amps × Ohms

Blown Speakers

Your speakers work using a voice coil, which is a tight coil of thin wire wrapped around a tube and surrounded by a magnet. When electricity passes through a voice coil, it becomes magnetized and causes it to interact with the surrounding magnet’s field. The resulting interactions produce vibrations that the speaker turns into sound.  

If that voice coil is damaged by being overdriven, two things can happen. The coil may break, forming an open circuit, or it may fuse together and form a short circuit.

If you check a blown speaker with an ohmmeter, a short circuit will read as 0 ohms, and a broken circuit will register as infinite resistance.  

An open circuit terminates at the breakpoint, leaving the current no place to go. A short circuit sends the current back upon itself, so if you connect the positive and negative terminals of a battery to each other with a wire, it will rapidly grow hot, and in some cases, it may explode within seconds.   

A speaker’s cone may also be torn by overdriving. If you are hearing rattling and popping noises coming out of one speaker, it may be damaged. The noises may be sporadic and may only appear when you turn your music up, but it is only a matter of time before this damage hits the voice coil.

You might want to replace your damaged speaker now instead of replacing your amplifier later.

Broken Wires

Your speakers might be fine, but your connections may be lacking. A crimped or broken wire leading to a door speaker may cause the sound to cut out and kick back in as the door is opened or closed.  

If a bare section of the speaker wire touches the chassis, any current which passes through will go straight to the ground (the car body). If your speaker connections are loose, the vibrations from loud music may jar them and knock the connecting wire away. And if the positive and negative wires come in contact with each other, your amplifier will read it as a short circuit and shut down. 

To check if you have broken wires, first, try playing your music by disconnecting all your speakers and then playing each individually.

If one of them cuts out to loud music, you have found the source of your problem. Replace the wires and be sure the new ones are tightly connected.

Final Thoughts

You don’t need to be an electrical engineer to troubleshoot your car stereo when your speakers start cutting out. But a basic understanding of how your system works and the various things that can go wrong will help you figure out what is wrong and give you ideas on how to fix it.

Now you have that knowledge. Happy listening at whatever volume you like!

Sources

Martin

Welcome to ImproveCarAudio! I am Martin, and I love to write about everything related to car sound systems. I strive to provide the most accurate and helpful information about car audio through extensive research, as well as my experience with car audio installations.

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