Speakers are, by a long way, the most influential component in any audio system when defining performance or quality. Low-quality speakers, or those without specific technologies, can’t match the clarity levels of premium solutions. In addition, many music enthusiasts want their car audio systems to play louder than what’s possible with factory-installed equipment. After all, jamming to your favorite music while going to work or school is a great way to start the day! Is upgrading the speakers the right solution? Let’s look at the physics of loudspeaker efficiency and output capability.

Car Audio Speaker Efficiency

One of the many reasons people ask to upgrade the speakers in their cars and trucks is a desire for the system to play louder. Unfortunately, most high-performance speakers aren’t as efficient as those that the manufacturer provided.

When shopping for speakers, you’ll need to look at the efficiency specification. This number describes the amount of sound a speaker will produce for a given signal from an amplifier. The standard specification describes the speaker’s output in dB SPL at 1 meter from the speaker when powered with 1 watt from an amplifier.

A second standard exists where 2.83 volts are applied to the speaker, and the output is measured at 1 meter. There is nothing wrong with the 2.83-volt rating, except that you have to consider the speaker’s impedance when comparing drivers. For example, a drive level of 2.83 volts equals 1 watt of power when driving an 8-ohm speaker, 2 watts when driving a 4-ohm speaker and 4 watts with a 2-ohm speaker.

The output of a speaker increases or decreases by 3 dB every time the power is doubled or halved. Therefore, be sure you’re comparing like numbers when comparing speaker efficiencies. If no drive level specification is provided, it’s safe to assume the manufacturer will choose the 2.83-volt measurement to produce the highest numbers.

Are New Car Audio Speakers Going To Be Louder?

A while back, we measured the output of a 6.5-inch speaker from a Honda Civic as part of our series on understanding speaker quality. Our measurements showed that this speaker had an efficiency of 89.04 dB SPL when driven with 1 watt of power and measured at a distance of 1 meter. So how does this number compare to common replacement speakers? First, let’s look at a few examples from Rockford Fosgate. I’ve chosen this brand as it has a variety of offerings and many price points and performance levels.

Starting with its most affordable option, the Prime Series R165X3 has a rated efficiency of 91 dB SPL at 1W/1M. You’d be able to hear this 2-dB increase in output. What if you want a better speaker? It seems logical to move up to one of the Punch Series drivers. The P1650 is a very popular replacement speaker, but it has an efficiency of 88 dB SPL at 1W/1M. Does this mean the speaker isn’t as good? No, it’s simply not as efficient. If you want an even better speaker, then the Power Series T1650 is the next step in the series. This driver also has an efficiency of 88 dB SPL at 1W/1M. So why are the better speakers not louder?

When a transducer engineer is designing speakers, they must balance many characteristics. How efficient will the driver be? How low should it play? How much power can it handle? How much excursion is required? Unfortunately, some of these characteristics oppose each other. A driver of a given size that is intended to play lower frequencies will need a lower resonant frequency. This lower Fs value is usually achieved by increasing the cone’s mass and softening the suspension. The increased mass of the cone assembly decreases the driver’s efficiency. An extreme example of this would be a 6.5-inch subwoofer. A typical 6.5-inch car audio subwoofer has an efficiency of around 80 to 81 dB at 1W/1M.

As you can see, the 6.5-inch midrange driver is much louder at higher frequencies. So, why not use it as a subwoofer? Well, it doesn’t have the power handling or excursion capabilities required to reproduce low-frequency audio and high volume levels. A typical full-range 6.5-inch driver might handle about 50 or 60 watts of power and have a maximum linear cone excursion of roughly 3 millimeters in each direction. An equivalently sized subwoofer might handle 150 watts of power and have 9 to 10 millimeters of excursion capability. Since we know that speakers need to move a lot more air to produce bass, it’s clear that the subwoofer would be louder at lower frequencies.

What About PA Speakers?

We have pro audio or PA speakers at the other end of the speaker spectrum. These drivers are designed for applications where the most output possible is required from minimal amounts of power. For example, let’s say you were responsible for setting up the sound system for a Metallica concert in an open-roof stadium. Many of these installations have about a megawatt of power driving the speakers and subwoofers. Assuming 220-volt, 30-amp circuits feed the amplifiers, the sound system would need more than 180 circuits. However, if you could find 3 dB more efficient speakers, you could get the same output for the audience from 90 circuits and half the amplifier power.

PA speakers use designs that trade low-frequency output for increased midrange output. For example, a 6.5-inch PA-style speaker might have an efficiency of 92 or 93 dB at 1W/1M. This would be achieved by lowering the mass of the cone assembly as much as possible. The trade-off would be output at lower frequencies. Unfortunately, many high-efficiency 6.5-inch speakers have an Xmax specification of only 1.5 to 2 millimeters. As a result, they sound horrific when used incorrectly and driven with midbass information in the 80-to-150-hertz range at high levels.

Unlike a car audio system, there’s no need to drive concert midrange drivers down to 80 Hz to help with the perception of bass frequencies sounding as if they’re coming from the front of the vehicle. Instead, the crossover point can be at 150 or 200 hertz, and the system will sound the same to the audience. If you look at the frequency response specification of a concert subwoofer, you’ll find that most are designed to play up to 200 hertz. You may also note that these subwoofers also call for a high-pass filter, or what car audio enthusiasts would call an infrasonic filter at 35 hertz.

As you can see from the graph above, the green trace shows that the speaker is much more efficient in the upper midrange, but at the expense of low-frequency output.

Which Speakers Are Right for My Car Audio System?

In general terms, you have two options for replacement speakers for your car stereo: You can choose from a number of relatively high-efficiency solutions like the X2 speakers from ARC Audio, Prime Speakers from Rockford Fosgate, Prima speakers from Audison or Uno speakers from Hertz. These are great choices if you use a radio with up to about 22 watts of power to drive them.

If you plan on adding an amplifier to your car audio system, your speaker choice might change to something like the ARC Audio ARC Series, the Rockford Fosgate Punch, Sony Mobile ES or Hertz Cento. These speakers can handle more power and have more excursion capability to play louder. With that said, they need more power to reach those output levels. A secondary reward for choosing better speakers is that they are typically clearer and more detailed.

When it’s time to upgrade your car stereo, visit a local specialty mobile enhancement retailer so you can audition the speakers they have on display. Talk to the product specialist about your long-term plans for your audio system, along with your immediate performance improvement goals. They can use this information to select speakers that will meet your expectations.

This article is written and produced by the team at www.BestCarAudio.com. Reproduction or use of any kind is prohibited without the express written permission of 1sixty8 media.

Adding an amplifier to your car stereo is a great way to improve its performance. If the amp is going to power speakers, you should be able to listen to your music at higher volume levels without worrying about clipping distortion. Of course, we all know that one of the best upgrades you can make to any car audio system is to add a subwoofer and a dedicated amplifier to drive it. Your installer will need a line output converter interface when connecting that amplifier to a factory-installed radio. Should you use a stand-alone unit, or is the converter built into a high-quality amplifier adequate?

What Does a Line Output Converter Do?

The audio signal from most car radios is designed to drive a speaker. There are two connections for each speaker, a positive and a negative. There are signals on both of these wires that we call a bridge-tied load configuration. Unfortunately, many low-quality amplifiers with single-ended input circuitry won’t work with this signal configuration and could damage the radio.

Most amplifiers are designed to produce their maximum output with signals ranging from a few hundred millivolts to 4 or 5 volts. The sensitivity or gain control on the amplifier adjusts how much signal it produces so it can work with various voltages. Bad things will happen if the radio produces more voltage than the amp input stage can handle.

To summarize, a line output converter reduces the radio signal to something the amp can handle. It also converts the signal from a bridge-tied load to a single-ended configuration that will work with any amplifier, even those low-quality units that don’t have differential or balanced inputs.

What Makes One LOC Better Than Another?

If you read our comparison of line output converters, you know that some do a good job of converting the signal from the radio and some add a lot of distortion while negatively affecting frequency response. Therefore, based on our research and testing, you’ll want to avoid transformer-based converters.

Beyond that, why would a person choose an external converter from ARC Audio, Wavtech or AudioControl over a converter built into an amplifier? There are two reasons.

The first reason you might need to use an external line output converter is to deal with high voltages. If you have an amplifier connected to the output of a high-power factory-installed amplifier, there may be as much as 40 volts on the speaker wires to contend with. Almost no analog-only amplifier can handle this much voltage. Your installer will need an audio frequency analyzer and an oscilloscope to determine the maximum voltage of the signal coming out of the factory-installed audio system.

Amplifier Activation Circuitry

Another reason you might need an external line output converter is if your chosen amplifier doesn’t have automatic turn-on circuitry. When an aftermarket amplifier is connected to an aftermarket source unit, a control wire on the radio tells the amp when to turn it on and off. Unfortunately, in 99% of upgrades that use a factory-installed radio, there is no wire available to tell the amp what to do.

Many high-quality line output converters include remote turn-on circuitry. These converters have a wire that can be connected to the remote turn-on terminal on your amp to activate it when you turn on the radio or start playing music.

Are Built-In Line Output Converters Good?

The last consideration in our discussion about line output converters is their performance. Is there a performance benefit to be had by using a premium external converter instead of one built into an amplifier? The answer depends on a few variables. If the LOC is connected to a simple radio with a built-in 18- to 20-watts-per-channel amplifier, using the converter built into an amplifier will be just fine. There are other considerations if the factory-installed audio system uses a Class D amplifier. Class D amplifiers MUST have a low-impedance load connected to their outputs to function correctly. You may have heard of load resistors or similar in discussions about connecting to a factory-installed audio system.

If your vehicle comes with a Class D amplifier, it needs something like the AudioControl LGD wired to the speaker terminals. Which of the AC-LGD devices your vehicle needs depends on the amp design. Your installer will know which they should use. Once these are in place, you can use the LOC built into an amplifier. An alternative is to use a LOC that has load-generating resistors built in. The Wavtech and AudioControl solutions include this feature.

When it’s time to upgrade the factory-installed stereo in your vehicle, drop by a local specialty mobile enhancement retailer. They can suggest the best products to deliver the sound you want and will install them to maximize their performance. For example, if they suggest an amplifier with a built-in line output converter, it could save you some money.

This article is written and produced by the team at www.BestCarAudio.com. Reproduction or use of any kind is prohibited without the express written permission of 1sixty8 media.

Though it only seems like last year, our 2019 article about the importance of test-driving a new car radio before buying is suddenly more important than ever. So let’s review some key factors and discuss a few new things you ought to test before purchasing a new radio for your car or truck.

Test the Interface

One of the most important reasons to try out a new car radio, especially a multimedia receiver, is to evaluate the responsiveness and simplicity of the interface. For example, years ago, I had a top-of-the-line navigation-equipped multimedia receiver in my Jeep Grand Cherokee SRT-8. The radio sounded amazing and had every feature imaginable at the time. Unfortunately, to make the radio as “cool” as possible, the manufacturer included a capacitive touch interface across the bottom of the screen. Whenever I went to adjust the subwoofer level from the on-screen menu, my fingers would accidentally touch this panel and bring up the radio’s configuration menu. It was very frustrating to use.

When shopping for a radio, you want to try to use it as you would in a vehicle. Is the volume easily accessible without looking at the radio? Can you change songs easily? Can you change sources easily? How quickly does the interface respond to your inputs? You would be surprised at how slowly some radios respond to inputs. You want the radio to act like a smartphone. It’s impossible to gauge responsiveness by looking at a picture or watching a video.

Will It Play My Music?

Another critical test is to confirm that the radio will play your music. We aren’t talking about rock versus country and heavy metal. Do you have a digital audio collection stored in a format other than MP3? If so, you’ll want to connect your USB memory stick to the radio you have in mind to see whether it will recognize your music collection. You’ll want to ensure that it can detect all the tracks on the memory stick, checking to make sure that software restrictions aren’t hiding some files. Check both the root and subfolders to see that all the tracks are listed and in the order you expect.

You’ll also want to know if the radio remembers the song playing when the ignition is turned off, then back on. In the same scenario, does it restart at the song’s beginning or continue where it left off? If you listen to concerts or something like an audiobook, this matters. Check to see whether the radio adds a pause between tracks. Pauses between tracks make listening to concert albums annoying. Also, test to see how long it takes for the radio to play music after you turn it on.

Will the Radio Work Correctly with My Vehicle?

You’ll want to ask the retailer how the radio will function with your vehicle. Will the illumination dimmer work? Will a factory-installed backup camera display properly? Can the radio buttons on the steering wheel work with the aftermarket receiver? Find out how the steering wheel’s up and down tracking buttons work when listening to the radio. Do they take you to the next radio station preset or seek the next frequency the radio can lock on to?

Smartphone Integration

Here’s the topic that was the inspiration for this article. If you plan to use Apple CarPlay or Android Auto, you must check that your phone and the software it’s running will work with the radio. More importantly, if you plan to use wireless CarPlay or Android Auto, you must test that functionality. Three popular Android-based smartphone brands don’t work with wireless Android Auto on some multimedia receivers. Based on some cursory research, the issue appears to be a hardware limitation, so hoping that a software update will resolve things isn’t likely.

Have Realistic Expectations That Manufacturers Can Help

If you’ve purchased a radio that doesn’t work with your device or how you want, you can ask the manufacturer if they’re working on an update to address the issue. That said, please don’t assume they can or will be able to fix any problems. The software in a multimedia receiver is complicated; changing one part can dramatically affect the other functions in a radio.

Testing an update can take weeks or months to ensure that one change doesn’t break anything else. High-quality radio manufacturers like Sony, Kenwood, Pioneer, JVC and Alpine have teams dedicated to testing multimedia receiver software. If they’re working on an update to an existing product, that often delays the delivery of new models for the following years. Updates that might affect the operation of a technology like Apple CarPlay must go to Apple for approval. That process can take half a year. Trust us; we’ve been through it.

We can’t say it enough: Before purchasing, you MUST test the radio you want to buy on a display board. When it’s time to upgrade the technology in your vehicle, drop into a local specialty mobile enhancement retailer and talk with one of their product specialists. Bring your smartphone and some digital audio files along to test that the radio they suggest will function the way you want once it’s installed in your vehicle.

This article is written and produced by the team at www.BestCarAudio.com. Reproduction or use of any kind is prohibited without the express written permission of 1sixty8 media.