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Can a Car Amplifier Be Too Powerful?

When searching for a car amplifier and looking at the variety of amplifiers available on the market, you may wonder if a car amplifier can be too powerful for your speakers.

Amplifiers can be too powerful for speakers when producing a lot more wattage than the speakers can handle. As a general rule, the total power of the amplifier (combined RMS for all channels) should not exceed 150% of the all speakers RMS the amplifier will power.

For example, a stereo amplifier for pair of speakers with RMS 100W each should not produce more power than 300W at the same impedance.

On the other hand, if the amplifier does not produce enough power for the speakers, it may cause sound distortion, clipping, or voice coil damage.

Tip: When searching for the amplifier to match the speakers, always check the continuous power (RMS) instead of the peak power. Producers often highlight the peak wattage as a marketing strategy, which is the maximum amount of power the amplifier can produce for a short time, which can be misleading.

But what’s more important is how much wattage it can produce continuously without damaging your speakers at the same as the speakers’ impedance.

For example, Kicker 46CXA3604T can produce 4x65W RMS at 4 ohms, which may be not enough for many speakers, but it also can make 2x180W RMS in bridged mode at 2 ohms, which may be too much for some speakers.

In the article below, I will explain how much power is optimal for the car amplifier and the consequence of too high wattage. 

What Is an Amplifier?

An automobile amplifier is a device that turns low-level audio signals into power that moves the cones in the speakers to make a sound. Amps with a higher wattage are more powerful and more expensive, but does that make them better? 

Among other elements, power needs are dependent on the music loudness level, how efficient the speakers are, and how much air space is in your vehicle. For example, a Sports Utility Vehicle (SUV) will require a higher wattage than a compact car. 

can car amp be too powerful

Although a car amp is not visible, that doesn’t mean it isn’t installed.

If the car was purchased with a stereo by the original equipment manufacturer (OEM), you most likely have a low-end unit. Since the purpose of an amplifier is to provide loud music without sound distortion, how much extra power should you buy? While online calculators will quantify the wattage, the true meaning and ramifications must be established.  

Amplifier Power

Amps are rated in terms of sustainable music power, the Root Mean Square (RMS), measured in watts, in order to make useful differentiation between units.

Manufacturers recommend maximum RMS power, a peak output wattage because if an amp is pushed beyond, sounds become strained. 

If the amp is a small unit and pushed to the full RMS limit, the sound is less than optimal. On the other hand, if the amp is more powerful and running at 20% capacity, there is plenty of headroom leftover. And headroom is an extra power reserve if the audio signal exceeds normal levels. Therefore, you cannot have too much power because the extra wattage prevents strained audio.

Furthermore, when adding a powerful amp, consider how it fits the system comprehensively. Read the following points to create the best situation.  

  • Update the speakers to influence car audio if adding a stronger amp, which to quality speakers.    
  • Replace coaxial with component speakers because the drivers are separated. An amp will filter and deliver cleaner low level sounds to each driver, making it easier to hear every instrument. In contrast, coaxial speaker drivers sit on top of each other, which causes a slight sound delay. 

When purchasing new speakers, take a look at efficiency ratings, which describe the difference in a percentage calculated according to how much wattage is output and how much is used. 

  • 0.1% through 0.5% is acceptable.
  • > 0.5% is excellent.  

If you want to increase speaker sound sensitivity ratings, you have to replace the speakers. The sensitivity rating is determined by the volume speakers discharge combined with the available power.

  • 84 through 90 dB is acceptable.
  • Over 90 dB is excellent.

To find out which sensitivity will suit your needs, you have to determine normal car noise. For instance, it’s louder driving with the windows down or on busy city streets. More amp power is needed to increase the volume without affecting the sound purity.

To customize your audio system to hear more bass, add a subwoofer and a substantial amount of power. The subwoofer alone will use more power than all of your speakers put together. 

For sound and safety purposes, it’s crucial to use the correct power cable and speaker wire gauge when installing an amplifier. Dummies.com developed a chart that takes away all of the calculations and estimations.

Other Considerations

The most basic amp offers a small control level because they are adjusted when installed, and the controls are hidden. More expensive amps can be controlled on the unit or from your Bluetooth phone. 

When choosing an amplifier, pay attention to the power quality, which is assigned a class, and is included in the efficiency rating. Class A/B is larger, more powerful, and expensive. Class D’s are smaller, less efficient but don’t run as hot. 

Although many advantages and disadvantages are discussed in this 9-minute video, one example is that distortion in Class A is lower and sounds generally sweeter.

Continue to learn more by watching this beginner’s guide to the differences between Class A, A/B, and D amplifiers. 

Online Calculators

Before purchasing an amplifier you have to calculate the correct wattage because the amp’s wattage must not be over the manufacturer’s recommendation, or the speakers may run hot and break. Use any of the many online resources from reputable companies. 

For example, Crown Audio’s calculator, Amplifier Power Required, includes equations and explanations. Or read the Apex Customs calculator, Car Audio Calculator, with step-by-step instructions and pictures, to evaluate electrical power in watts.

Amp Wiring Kit

A car amp wiring kit will make the connections and bring power to the speakers. While there are many choices online, the Complete 3000W Gravity 4 Gauge Amplifier Installation Wiring Kit Amp Pk2 4 Ga Blue includes all of the necessities in your quest to identify and use the correct wattage and gauge for installation. 

Installation

As demonstrated in this 4-minute video by Crutchfield, learn step-by-step amplifier installation. Remember to find the appropriate spot to mount the amp, keeping in mind that the component generates heat, thereby necessitating placement in a ventilated area. Accordingly, the unit is often placed in the trunk or under the passenger car seat.

What Happens if a Car Amp Is Too Powerful?

The more powerful the amplifier is, the greater the musical sound. However, issues can surface if the amp is regarded separately instead of as a component integrated into a system working together to create high-quality audio sound

Consider the current or flow of electrical charge, as defined by Merriam-Webster. A power supply is rated at a voltage that can be tolerated before overheating and shutting down.

In short, if the volts are too high and the amps are too low, that is a dangerous situation. 

An amplifier cannot be too powerful, assuming the car’s alternator can handle it. If the dash and headlights are dimming, the alternator may be overloaded, which can cause damage. Alternators are rated in ampere (amp) units, which measure how fast the electricity is flowing, thereby determining the amp’s power. 

The following table is a general guideline using estimates, but manufacturers can provide the exact calculation and recommendation for purchasing an amplifier with the maximum wattage.

Also, if you are determined to buy an amp with a higher wattage, you can, as an alternative, buy and install a more substantial alternator replacement part.

Automobile SizeAlternator AmperesMax Wattage
Small car35300
Large Sports Utility Vehicle1451,200

The question should be, what is the optimum amount of power the audio system can withstand because more power means a deeper sound and richer tone to your music?

Every car audio system is slightly different but can be customized, but if your budget allows: 

Purchase a component speaker system, paying attention to the manufacturer’s limitation on RMPs. Higher RMPs allow the speakers to be paired with a higher wattage amp, resulting in a more powerful system. 

Within the speaker system’s constraints, buy an amp that fits within the limitations of the alternator. If that isn’t enough power, upgrade the alternator with a heavy-duty replacement part. 

Final Thoughts

The amplifier plays an important part in the character of the music and how sound is perceived. Amps deliver sound frequencies to the correct speakers, to electromagnetically move the sound, and drivers translate those signals into vibrations to be heard.

The more power your amplifier has, the better in order to create extra headroom and prevent straining. 

Remember, an amp is only limited by its dependencies on the rest of the system and your most superior sound determination. 

Buy the most powerful amp for your system, and jump from good to excellent audio experience.