The next topic in our look at car audio amplifier specifications is input sensitivity. This specification is easy to understand but is important to choose an amp that will work with the system your local car stereo shop has designed. In the simplest of terms, the sensitivity specification determines how much voltage is required on the input of the amplifier for it to produce full power. Let’s look at it in more detail.

Understanding Amplifier Input Sensitivity Range

Using our high-quality two-channel amp, our measurement equipment can show us just how much, or little, signal is required to produce a specific signal from the amp. We are going to use an output level of 10 watts for this example to keep our bank of load resistors cool and power supply happy.

With the sensitivity controls set to their lowest level, our amplifier produces 10 watts of output (6.32 Vrms) from about 1.4 V of input signal. This ratio equates to a system gain of 12.34 dB.

With the sensitivity controls on the amplifier turned to their highest setting, the amp amplifier is capable of producing 10 watts of output (6.32 Vrms) from a mere 54 millivolts rms of signal. This ratio equates to a gain of 41.41 dB.

Why Does Amplifier Sensitivity Matter?

Being able to get full power from your amplifier from a variety of signal sources is important to ensuring that your installer can make that amp work with any source. If you have a high-quality aftermarket source unit, the preamp outputs should provide 2 or 4 Vrms of signal with the volume at maximum and a recording at 0 dB.

If you are trying to power an audio system from something like an iPod, you may find that the signal from the headphone jack peaks around 1 Vrms. I tested one of my iPod Nanos at 1.03 Vrms. This lower maximum level means you need more gain from your amplifier.

At the other end of the scale, you may want your installer to connect your amplifier to the speaker outputs of your factory radio or factory-installed amplifier. The voltage from these sources may be as much as 8 V from a radio and could be as high as 40 V from a high-powered factory subwoofer amp. In those cases, you need to choose an amp that has dedicated speaker-level inputs or implement some sort of level converter to reduce the signal to something that the amp can accept.

System Tuning with Input Sensitivity Controls

When it comes to having a fully active audio system installed in your vehicle, unless you choose to implement a stand-alone digital signal processor (DSP), you will want to choose an amp with a lot of adjustability so that your installer can use the sensitivity control to reduce the output of the amp for the tweeters and midrange speakers, relative to the subwoofers and mid-bass drivers. You may find it useful to choose an amp for your tweeters that doesn’t produce a lot of power. Less maximum power output capability will reduce the amount of gain designed into the amp and result in a system that is easy to balance.

We would strongly recommend using a DSP since it enables you to configure crossover and output level adjustments quickly, but we understand that every audio system upgrade has budget limits. You can always upgrade later.

A Comment on Background Noise

If you have understood this article fully, then you realize that more signal from your source unit doesn’t necessarily represent an ability for your amplifier to produce more power, assuming the input sensitivity control is adjusted properly.

Years ago, when aftermarket source units with high-voltage preamp outputs were introduced, some companies marketed them as allowing stereo systems to play louder. If you didn’t adjust the sensitivity controls on your amp, this was a true statement.

The real benefit of a strong preamp signal is that you can turn down the gains on your amp and subsequently reduce the background noise in your system. Look at the difference in background noise of our high-end audio amp with the gain set at minimum and at maximum. Not all amps perform this well. As long as you can get full power from your amp, less gain means less background noise.

Choose an Amp That Works with Your Car Audio System

In most cases, the name-brand amplifiers available on the market today have the input voltage flexibility required to work in almost any application. Your local mobile enhancement retailer would be happy to work with you to pick a solution that will maximize the performance of your system.

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.

Welcome to our new series about understanding product specifications. Our goal in these articles is to help you understand what the amplifier power ratings mean when you start to compare solutions. We’ll not only explain which numbers are good, but we’ll include a detailed description of what each specification means, how it’s measured and how it affects what you hear or experience. To start the series, let’s look at amplifiers. It’s a subject we’ve chosen because people tend to focus on amplifier specifications more than anything else when shopping.

Why Your Car Audio System Needs Power

Without a doubt, the most popular specification that consumers look at when purchasing a car audio amplifier is its power rating. An amplifier takes the small signal from your source unit and increases it in voltage and current to drive a low-impedance speaker. In a nutshell, the more power you have, the more loudly you can play your car stereo system before the signal going to the speakers distorts. The limit of how much power is required is determined by the power handling specifications of the speakers in the vehicle, their cone excursion limits and their distortion characteristics. We’ll look at those limits in a future article about speaker specifications.

How We Measure Power

When an amplifier is set up in a lab to measure power, it’s typically connected to a power supply and a set of load resistors. Many manufacturers use test equipment from companies like Audio Precision to measure the distortion characteristics of the output signal to determine the point at which you would hear the distortion.

The Consumer Technology Association (formerly the Consumer Electronics Association) has established a standard for the power and signal-to-noise ratio measurements of car audio amplifiers called CTA-2006-B (formerly CEA-2006-B). The specification states that power measurements are to be taken with the amplifier powered with a voltage of 14.4 volts, and the measurement is taken into a specified load (typically 4 ohms) with no more than 1 percent total harmonic distortion and noise, across the entire bandwidth of the amp.

In layman’s terms, the amp must perform as well producing bass as it does high-frequency information, and the specified power rating cannot include large amounts of distortion. While the 14.4V rating is somewhat high, it establishes a level playing field from which consumers can compare results.

Several companies include additional power measurements to highlight different characteristics and performance features of their products. JL Audio, for example, includes output power ratings tested at 12.5 volts. Rockford Fosgate includes dynamic power ratings taken using the IHF-202 standard. Essentially, the dynamic power rating demonstrates the reserve capacity of an amplifier’s power supply to drive transient signals that last no more than 20 milliseconds.

Do Some Manufacturers Cheat?

If you don’t see the CTA-2006 logo associated with a product you are considering, there are several ways that the numbers may not be directly comparable with other options. One easy way to inflate numbers is to increase the supply voltage to the amp. Depending on the design of an amplifier’s power supply, each additional volt provided to that power supply could theoretically increase the amplifier’s output by about 0.6 dB. That would be like a 100-watt amp being able to make about 115 watts.

Not specifying a distortion rating is another great way to fudge the numbers. Most Class AB amps can produce 60 percent to 70 percent more than their 1 percent rated power if they are driven hard into clipping. Of course, the music no longer sounds like music and you run the risk of damaging speakers because they’ve been over-powered.

Finally, some amplifiers have problems with producing power at the extreme ends of the frequency spectrum. To be compliant with the spec, the amp needs to make the rated power level at 20 Hz through 20 kHz, or whatever the upper limit is for the design.

Do Amplifier Power Ratings Really Matter?

If you are shopping for an amplifier, the power rating does nothing to tell you about the quality of one amplifier compared to another. You don’t need 100 watts to drive your tweeters and you certainly won’t be happy with a 25-watt amp driving a subwoofer in your car.

When you are comparing amplifiers, don’t get your knickers in a knot over a few watts. This applies specifically to amplifiers that come with birth certificates (documentation that states a particular amplifier’s power production capabilities). You can’t hear the difference between an amp that makes 300 watts and one that makes 305 watts. That difference would be a mere 0.07 decibels. You will hear a difference between a subwoofer amp that produces 100 watts and one that can deliver 300 watts.

We’ll add a note about “how things work” here. To increase the output of your audio system by 3dB, you need an amp that can produce twice as much power. So, to go from 90 dB in your car, you need twice as much power from the amp to raise the volume to 93dB and twice as much again to get to 96dB.

Shopping for a Car Audio Amplifier

When it’s time to go shopping for a car audio amplifier to provide more power to your speakers, drop into your local car stereo shop and speak with one of their product specialists. They can help you determine how much power is appropriate for the system you have in mind and choose an amp that sounds great and works with your budget.

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.

Did you know that in Europe, there aren’t nearly the number of qualified car audio installers that there are here in North America? In some countries, shops that primarily sell wheels and tires are the most popular choice for purchasing and installing audio system upgrades. Manufacturers that want to provide consumers with premium sound system upgrades have turned to developing vehicle-specific audio upgrades that don’t require any fabrication skills to install. In this article, we’ll look at what makes these a great solution to upgrade your audio system quickly and easily.

What Makes an Application Vehicle-Specific?

Let’s look at speakers for the discussion of what makes something vehicle-specific. If your pickup truck comes from the factory with a 6×9-inch speaker in the door, there are hundreds of options available that will bolt right in. On the other hand, if you have a vehicle like a Subaru WRX, where the factory speaker includes a large semi-triangular mounting bracket with three holes, your local car audio installation technician will need to create a mounting adapter to install a new 6.5-inch woofer or coaxial speaker in the door.

Vehicle-specific audio upgrades typically involve two items: the inclusion of application-specific speaker mounting brackets and electrical connectors designed to work with the wiring already in the vehicle. In short, no fabrication is required to install these products, and the installation doesn’t require any modification to any part of the vehicle.

Vehicle-Specific Subwoofer Upgrades

When you say the word subwoofer to someone, they often envision someone driving down the street with a wall of woofers, shaking windows and being otherwise annoying. The reality is, adding a subwoofer to even a premium car audio system is one of the best upgrades you can do.

Recreating music below 80 Hz takes a lot more power and speaker excursion than higher frequencies require. Letting a sub and a dedicated amp take care of the bottom few octaves not only adds bass that was likely missing, but alleviates the need for the smaller speakers and low-power amplifiers to try and produce that sound. The result? Every aspect of your audio system will sound clearer and more detailed.

Companies like JL Audio, Atrend, Bassworx, MTX, Audio Enhancers, Alpine and many more have subwoofer enclosures designed for specific cars and, more importantly, pickup trucks. These enclosures fit into the trunk, spare tire area or corner of a car trunk. For pickup trucks and SUVs, solutions exist for under rear seats, behind seats, in center consoles and to replace inadequate factory subwoofers in the back of SUVs.

Add an Amplifier with a Digital Signal Processor

Another way to upgrade BMW> and Mini (they use the same speaker and subwoofer sizes) audio systems is to add an amp with an integrated digital signal processor. The extra power will let you turn up the volume without distortion. More importantly, the DSP in the amp can, in the hands of a skilled technician, dramatically improve the tonal balance of your audio system. Installing an amp before upgrading the speakers is a great way to build your system in stages and ease the impact on your wallet.

Are These Do-It-Yourself Kits?

The answer for the majority of our readers is no. Sure, the speakers bolt into the factory locations and the subwoofer systems may include instructions on how to install them. If you are a handy do-it-yourself kind of person and have experience taking the interior of a vehicle apart, you may be able to complete the install.

If you don’t know the tricks or don’t have the tools to remove the door and trim panels, or you don’t know how to test the frequency content of the factory radio or source unit in your vehicle, then having a trained technician perform the installation is a wise investment.

If the upgrade includes an amplifier for a sub, the speakers or the entire system, setting the crossover and sensitivity controls accurately takes some experience. Sure, almost anyone can experiment with these settings, but a qualified tech can set them in about 15 to 30 minutes, depending on the number of amplification channels involved.

Finally, if you have (wisely) chosen to add a digital signal processor to your sound system, you need specialized equipment and training to optimize its features. The process varies a great deal depending on the configuration of the factory sound system. If you don’t have the right training, the results can be unimpressive.

Upgrade Your Factory Stereo System Today

Even without touching the radio in your new car, your local specialist mobile electronics retailer can dramatically improve every aspect of your sound system. Combining their skill with premium vehicle-specific products can transform your daily commute into a relaxing or invigorating musical experience.

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.

Understanding how to recreate music in our vehicles is a complicated science. Balancing speaker sizes and locations with the goal of recreating what the recording engineer heard in the mastering studio or, at the very least, making your system enjoyable isn’t always easy. We want to take a look at the physics behind sound and explain a few fundamentals of how sound works to help you understand the terminology used in the automotive audio industry and why a balanced system design with the proper equipment is crucial to creating an enjoyable and realistic listening experience.

What is Sound and How Does It Work?

At the most fundamental level, sounds are vibrations that travel through air and other mediums. These vibrations are detected by our ears, which in turn convert them to minute electrical signals that our brains interpret.

Because we have two ears, our brain can determine the location of a sound source by analyzing the arrival time and frequency content of what each of our ears hear. For example, a sound that is created directly in front of you will arrive at both ears simultaneously and with equal frequency response. A sound that is created directly to the right of us will arrive at our right ear before our left. The amplitude of the sound will be slightly higher in the right than in the left. Also, the high-frequency content of the sound that arrives at our left ear will be different. We learn as we grow up to correlate different visual cues with what we hear to develop a sense for where the sound comes from.

Recreating Sound and Music

Much like the way signals from our auditory nerves send electrical messages to our brains, sound waves (or vibrations) can move a microphone diaphragm to create an electrical signal that a recording device can store for playback at another time. The image below is an electrical representation of someone saying the word hello. You can listen to the original audio file by clicking here.

The image shows us a graph of voltage versus time, with voltage on the vertical scale and time on the horizontal. The amplitude (level) of the signal determines its intensity (or loudness). The speed at which the signal changes determines frequency. Understanding the interactions of simultaneous frequencies is fundamental to understanding why similar sound sources produce different sounds.

The graph below shows the average frequency content of the person saying hello. You can hear the audio file by clicking here

When a performer is singing or someone is playing an instrument, the sound of that instrument is determined by its harmonic content. For example, a Middle C on a piano and Middle C on a guitar are based around similar frequency content. The following recordings show the majority of energy at 261 and 522 Hz. Here is the Middle C note on the piano and here is the note on the guitar. You can see that the average harmonic content of each is quite different.

If we focus on just the main 261 and 522 tones with a steep band-pass filter set to 120 and 650 Hz, the two instruments start to sound very similar.

Filtered Piano Sound

Filtered Guitar Sound

As you can hear, the “sound” of an instrument depends heavily on its harmonic content and relative balance (amplitude) of that information.

Car Stereo System Frequency Response

So, why are we dwelling so much on the fact that sound of different instruments and performers is based heavily on harmonic frequency content? When it comes to time to design an audio system for your car, truck, boat or motorcycle, it’s important that the system performs evenly across the entire audio spectrum in order for your music to sound realistic.

To achieve this goal, you need at least a two-way speaker system. Because no single speaker can reproduce the entire audio spectrum (from deep bass to the highest highs) with good efficiency and dispersion, we dedicate different size drivers to different frequency ranges. In the simplest of systems, you’d have woofers (not to be confused with subwoofers) that play frequencies below about 3,000 Hz. For the top end, you’ll need tweeters to cover the frequencies above 3,000 Hz.

For even better performance, you may want to add a subwoofer to the system to relieve the woofer of the task of reproducing those frequencies below about 80 Hz and dedicate them to a larger speaker that is more efficient in that range. It also takes a lot of energy to reproduce bass information, so you’ll want a moderately powerful amplifier available to drive that subwoofer. If you have 25 watts of power available to drive your left and right speakers, 250 watts would be a good starting point for your subwoofer.

Creating an Amazing Mobile Audio System

The last step in creating a car stereo system that sounds good is to ensure that the placement of each of the speakers in the vehicle allows for equal and balanced frequency response from both sides of the car. This is crucial to creating a realistic listening experience. With that said, most of us start with a set of coaxial or component speakers in the stock door locations. This puts our listening position quite far off-axis to the left side driver as compared to the right. For most people, the sound isn’t too bad and they can live with the minor differences, especially if the tweeters are angled up and rearward to deliver similar high-frequency response.

If you want a truly enjoyable and realistic listening environment, consider adding a digital signal processor that allows your installer to fine-tune the output of the left and right speakers at all frequencies so that they sound the same. If your installer knows how to sprinkle in the right amount of time delay so that the output of the right speaker arrives at your ears at the same time as the left, well, chances are you’ll enjoy an impressive soundstage in the vehicle. Your music will be spread evenly from left to right, and with the right recordings, you’ll be able to pick out each instrument or performer and their relative location to one another cross this soundstage.

Experience Amazing Audio in Your Car Today!

Now that you have a basic understanding of how sound, works, it’s time to upgrade your car audio system. Drop by your local mobile enhancement retailer and ask about a subwoofer, a DSP-equipped amplifier and new speakers. The difference you’ll hear with each of these upgrades will blow your mind and put a smile on your face.

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.