Specialty mobile enhancement installation technicians couldn’t upgrade the audio systems in our cars and trucks if they didn’t have access to high-quality, correctly sized wiring. Whether they are connecting a pair of speakers to a radio or running large power and ground wires from a battery to an amplifier, wiring and its size is crucial. There are a lot of myths and misunderstandings when it comes to wiring. Let’s break down a few and look at the truth.

For this article, we are going to talk exclusively about all-copper conductors. The alternative to copper is copper-clad aluminum (CCA). Aluminum adds unwanted resistance and reduces the power delivery efficiency of our audio systems. Pound for pound, aluminum is 61% as conductive as copper. One of the most significant issues with CCA amp kits is that it’s impossible to determine the ratio of copper to aluminum. In most cases, the size of the wire does not meet the American Wire Gauge standard.

Myth #1: If it’s not CCA, it’s OFC.

As with any industry, people like to throw buzzwords around. One that gets sprinkled around liberally is the acronym OFC, which stands for oxygen-free copper. Oxygen is a critical component in the smelting of copper. Oxygen is injected into the molten mixture that helps extract impurities that would degrade the resulting product.

High-conductivity copper does exist. Compared to the International Annealed Copper Standard (created in 1913), many modern, low-impurity coppers can achieve conductivity that reaches 101%. The standard, for those who are interested, is 0.15292 ohm for a copper mass of 1 gram with a uniform cross-section and a length of 1 meter.

Specifically, stating that a copper conductor is oxygen-free doesn’t mean that it’s pure or offers exceptional electrical conductance. In most instances, OFC car audio wiring is simply an alternative to copper-clad aluminum solutions. Much of it is made from recycled copper and contains other metals like tin.

Interestingly, the CEA-2015 standard for car audio conductors specifies a maximum resistance of only 93.15% of the IACS standard.

Myth #2: Your Small Speakers Need Big Wire

Initially established in 1857, the American Wire Gauge standard was created to identify the size of solid electrical conductors and, consequently, their ability to pass current without significant voltage loss. The gauge system is based on the number of draws of a conductor through a die, with more draws (higher gauge number) resulting in a smaller-diameter wire. The standard for standard wires is different than for that of solid wire.

As we discussed in our article about speaker power handling, most midrange speakers and tweeters receive only a few watts of power, even at high volume levels. If we use the example of a tweeter and make the assumption we are going to drive it incredibly hard with, say, 10 watts of power, we only need to deliver 1.5 amps of current during the highest peaks in our music.

Since all conductors add resistance to a circuit, they should be sized to provide an acceptable amount of signal loss for a given distance. The CTA-2015 Mobile Electronics Cabling Standard notes that a 20-AWG cable with a length of 21 feet will deliver 80 watts of power with less than a 1 dB drop in output. This does take into account the total length of both conductors in a cable.

Myth #3: Amp Kits Should Have Power Ratings

Decades ago, Phoenix Gold (and many other companies) published charts that outlined power wire sizes based on amplifier power ratings. As a general rule of thumb, these were helpful. However, without specifics about allowable voltage losses between the battery and alternator, and the amplifier, the numbers are somewhat meaningless.

We’ll look at a brand-name amplifier installation kit that includes what they describe as full-AWG spec 4-gauge pure copper power wire in a length of 18 feet. The kit is rated for 175 amps of current and is said to be compatible with a 1750-watt amplifier.

Assuming it complies with the CTA-2015 standard, the power wire will have a maximum resistance of 28.346 milliohms per foot, for a total of 5.102 milliohms for the length of the cable. If we pass 175 amps of current through that cable, we get a voltage drop of 0.89 volt.

The CTA spec for acceptable voltage drop is 0.25 volt. As such, a high-quality 4-AWG power kit would have a maximum power rating of about 50 amps for an 18-foot length. Keep in mind, this only takes into consideration the positive conductor. Your ground cable and the resistance of the vehicle chassis also need to be taken into account. In short, you are likely running too small of a power cable.

Get the Right Size Wire for Your Car Audio System

When it comes to power delivery to your amplifiers, bigger cables are always better. When it comes to running speaker wire to your mids and tweeters, you don’t need 12-AWG. If you are planning on having your car stereo upgraded, visit your local specialty mobile enhancement retailer and ask them about the size of power and speaker wires they will be using in your installation.

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.

If you’ve purchased a car or truck in the last five to 10 years, there’s a good chance that the stereo system is integrated with the climate control and vehicle configuration system. Without an interface to extract a high-quality pre-amp audio signal, upgrading these vehicles with new speakers, amplifiers or a subwoofer can be difficult and unpredictable. Companies like Nav-TV, iDatalink, PAC Audio and mObridge offer dedicated, high-quality solutions that will let your specialty mobile enhancement retailer install a premium audio upgrade that will sound amazing.

Audio Data Networks

Vehicle manufacturers are always looking for ways to reduce weight in new cars. If they can save the weight of a single wire that runs from the dash to the trunk, they’ll do it. Technologies like the Media Oriented System Transport (MOST) and Automotive Audio Bus (A2B) are digital communication protocols that allow multiple audio channels to be transmitted over a pair of wires. These networks not only reduce wiring needs but are impervious to noise interference. As such, conventional twisted-pair wiring is often adequate.

Another popular option for signal transfer is to transmit a fixed-level stereo audio signal from the source unit to the amp. The pre-amp inside the amplifier is controlled by network commands that tell it when to adjust the output volume. These commands are sent from the controllers in the front of the vehicle to the amplifier over the CAN data bus.

The problem with these systems in terms of upgrading your stereo is that you can’t just tap into the wires to extract an audio signal that will connect to an aftermarket amplifier.

Connecting Amplifiers to Factory Stereos

For decades, audio system upgrades have been executed using speaker-level to pre-amp adapters. These solutions work great when the audio signal coming out of the amplifier has been tested to confirm frequency response, level and bandwidth. Given the complexity of modern source units and amplifiers, making the assumption that the signal is usable can quickly lead to poor audio system performance.

 

Car audio pre-amp interfaces install in place of a factory-installed amplifier. These interfaces provide six or more analog pre-amp audio outputs, just like you’d see on the back of an aftermarket radio. The audio signals contain all the audio information from the lowest bass signals to the highest of highs. There’s no equalization, no all-pass or phase-EQ filters or time alignment, ensuring that your dealer can design and install a system that will sound great.

Pre-amp Interfaces Eliminate Noise Cancellation Issues

Using a pre-amp interface also eliminates issues with active noise cancellation (ANC) that can wreak havoc with subwoofer upgrades. Noise cancellation systems use microphones to analyze the sound in the vehicle, then produce sounds through the factory speakers that cancel unwanted noises. These ANC systems are calibrated to the exact microphone locations and the output of the factory speakers. Something as simple as adding sound deadening to a door can adversely affect the response of these features. Of course, new speakers, a more powerful amplifier or the addition of a subwoofer make an even bigger mess. Using a high-quality pre-amp interface eliminates the ANC system, allowing audio upgrades to function reliably.

If you are concerned about a small increase in noise, adding high-quality sound deadening to the doors, floor and firewall can make a massive difference in the comfort of the vehicle.

Ensure that Your Audio System Is Upgraded Reliably

As the features and performance of factory-installed audio systems increase, car audio upgrades are more complicated than ever. You can enjoy an impressive improvement in output level, sound quality and detail from even a simple upgrade, as long as the system is designed properly. Drop by your local specialty mobile enhancement retailer today to find out what they can do to make your car stereo sound amazing.

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.

When it comes to good car audio speakers, it’s universally accepted that we’re talking about smooth frequency response and a lack of distortion. Buying a set of good car audio speakers can be a daunting task, with options that vary from well under $50 to over $5,000. Can a cheap speaker sound good? Let’s look at what makes speakers the most crucial component in an audio system in terms of sound quality.

Is Loud Music Good?

It’s relatively easy to design a speaker that sounds fine at low volume levels. For a typical door speaker, like a 6.5-inch component or coaxial solution, low volume levels mean limited cone excursion requirements. As such, the design of the speaker is less reliant on motor geometry and suspension linearity. If we decide we want to get a lot of output from a speaker, then the designer needs to ensure that the cone will move through its range of motion proportionately to the signal. Achieving this level of linearity can be difficult. Changes in voice coil inductance based on cone position combined with magnetic field and suspension compliance non-linearities can wreak havoc with the sound produced by the speaker. When not executed properly, undesirable harmonic and intermodulation distortion are added to the sound you hear.

Power Handling and Output Level Considerations

A speaker’s power handling specification is typically determined and limited by the diameter of the woofer’s voice coil. Speakers with 1-inch coils are usually good for continuous power handling ratings up to 70 watts. 1.25-inch coils are rated around 80 watts and 1.5-inch coils can handle 100 watts without damage. Some companies seem to over- or underrate their power handling specs. We’ve seen woofers with 2-inch coils rated for 100 watts and 1.5-inch coils for 120 watts. Suffice it to say that larger (and longer) coils can dissipate more thermal energy. Simple features like the addition of a black coating on the voice coil winding can help to improve heat dissipation. Since car audio speakers are notoriously inefficient (~1%), power handling is important if you are going to crank up the volume.

When it comes to playing music at high volume levels, you need to move air, especially for bass frequencies. There are two parts of a speaker that determine how loudly it can play: the suspension components like the surround and spider and the length of the voice coil winding, and the height of the motor top plate. Though there are exceptions, you can often get a good feeling for a speaker’s ability to play at high volume levels by looking at its Xmax specification. While most car audio enthusiasts associate Xmax with subwoofers, it’s equally relevant when talking about midbass and midrange woofers that play below 400 Hz. If your door or rear speakers are to produce audio information down to 80 Hz, they’re going to need to work hard. Most 6.5-inch midrange and midbass drivers have an Xmax specification of 4-6 mm, though some truly exceptional examples get up to 9 mm.

So, what happens when you push a speaker farther than it’s designed to play? First and foremost, distortion skyrockets. The extra power from the amplifier doesn’t produce a directly proportional increase in sound output. If the speaker suspension isn’t designed to properly limit cone motion, the voice coil former can run into the backplate on the rearward stroke. The sound is similar to hitting a heavy saucepan with a car key. In a best-case scenario, this interference produces an unwanted sound. Worst-case? The former can be deformed and become stuck in the gap between the top plate and T-Yoke.

Can a Cheap or Poorly Designed Car Audio Speaker Sound Good?

Let’s theoretically compare two speakers. Our cheap speaker is very basic: It has a cupped spider, 1-inch voice coil, an undamped polypropylene woofer cone with a lightweight dust cap, and a high-pass filter on the tweeter. Our premium speaker uses a well-damped paper woofer cone, a 1.5-inch voice coil, a flat spider, a proper two-way passive crossover network and adds an aluminum shorting ring and a copper T-yoke cap. If they’re calibrated to play the same frequency response with pink noise, will they sound the same with music? No, they won’t. Why? Distortion.

Nobody Talks About Speaker Distortion

Distortion is the addition of unwanted information in an audio signal. Harmonic distortion adds sound not originally in the recording and even and odd multiples of an original signal. Intermodulation distortion is the creation of unwanted information that is the difference between two frequencies being played simultaneously.

Because music is made up of a very broad spectrum of frequencies, when unwanted information is added, it changes what we hear. The sound of a single piano note or the strum of the guitar string is colored with information that wasn’t originally produced by the instrument. In the same way that the harmonic content of a piano playing the same note as a guitar makes them sound different, the distortion added by a speaker makes the resulting performance less real and less convincing.

The Photography Analogy

Think of speaker quality in the same way you’d think about buying a camera and taking photographs. If you buy a $50 camera from Walmart and a $1,000 camera from a dedicated camera store, you still end up with a pair of tools that will capture an image of a scene. The cheap camera will tell you everything you want to know about the color and location of an item. Say, a blue car parked at the side of the road in front of a brick building. The expensive camera may capture enough information to let you read the brand of the tire from the sidewall and see the quality of the brickwork in the building. Both tell the same message; one does it with more detail and accuracy.

Good Speakers are Crucial to Great Sound

Shopping for speakers for your car audio system takes time. Invest in auditioning the best solutions available for your budget by listening to as many examples as possible. You’ll quickly realize the traits that evoke clarity and accuracy that differentiate the mediocre speakers from the good and great. Finally, make sure the speakers are installed properly and your system is configured by a professional to ensure reliability and the best performance. Visit your local specialty mobile enhancement retailer to begin your quest for great sound in your car or truck.

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.

For well more than a decade, respectable mobile enhancement retailers around the world have understood the need for a digital signal processor to be included in any car audio system upgrade. Even if you’ve chosen the lowest-distortion speakers on the planet and your installer has agonized over placement and integration, they still need a way to compensate for the peaks and valleys in the frequency response that come with the confines of a vehicle interior. The same process is used to calibrate home and commercial theater systems, recording studios, clubs and concerts. Let’s look at a few reasons why having a DSP in your system is crucial to achieving realistic sound.

Accurate Crossover Settings

One benefit of having your installer tune your audio system with a DSP as opposed to an analog processor with knobs is accuracy. The potentiometers used on amplifiers and stand-alone processors are notoriously inaccurate. Your installer could turn a dial on an amplifier to a setting labeled 80 Hz and end up with an actual crossover point of anything from 70 to 90 Hz.

Because digital signal processors use mathematical algorithms to alter the audio signal, they are incredibly accurate. Your installer can set a high-pass filter at 2,500 Hz for your tweeters and know that there won’t be any issues with power handling from unwanted midrange energy. The same applies to a low-pass filter at the top of the midrange driver. You don’t want any overlap or underlap (a gap in the frequency response) that could affect frequency response.

Taming Frequency Response Issues

To keep this discussion simple, let’s use a two-way bookshelf speaker on a desk as our reference for measurements. The speaker uses a 5¼-inch woofer with a glass fiber/foam core cone and a hard dome tweeter. Half of an eight-channel amplifier with integrated digital signal processing powers the speakers in a fully active configuration. This last statement means there is a pair of amplifier channels dedicated to the woofers and a second pair dedicated to the tweeters. No passive crossovers are used anywhere in the system. These speakers are used in conjunction with a dedicated subwoofer, so a high-pass filter has been applied at 80 Hz.

If we measure the frequency response of the woofer and tweeter with the mic close to their respective cones, we see the response curves shown in Graphs 1 and 2. You can see that the response of the woofer is relatively flat, with no significant peaks or dips at any frequency.

If we take a second measurement (Graph 2) of the entire system (both the woofer and tweeter playing at the same timer) at a distance of one foot from the speaker, we can see that the reflections from the desk and nearby objects have imposed peaks and valleys in the response curve. The deviation is more than 13 dB. These changes add emphasis to specific frequencies, changing the tonal balance of the speaker and detracting from the accuracy of the listening experience.

If we apply compensation using the equalizer built into the amp, you can see that the response at the listening position is smoothed. The natural balance of the audio signal is much more realistic at the listening position.

The interior of your vehicle imparts much more significant changes in response because of the abundance of glass, vinyl, plastic and carpet surfaces. Proper equalization is even more important in your car or truck in terms of achieving great audio performance.

Just as with our explanation for the need for accurate crossover settings, using a DSP will allow for precise amounts of equalization. If the system needs a cut of 2 dB at 1 kHz, 4 dB of boost at 320 Hz and 3 dB of cut at 80 Hz, the DSP can deliver with exacting precision and repeatability.

Pathlength Compensation

If the product specialist you’re working with is designing what’s known as a single-seat audio system, then they will want to adjust the output of each speaker in the car or truck so that the sound arrives at your ears at the same time. Compensating means adding delay to the signals going to the closest speakers. Processor calibrations that provide good imaging for both seats are also available, but use a different tuning process with no left-to-right signal delay

The result, when executed properly, is that the music you hear will seem to come from a point between all the speakers. In most cases, this puts the performance on what’s known as a virtual soundstage that spreads the width of the vehicle. If the equalization process was executed properly, each performer should be placed in their relative position across the stage. This phenomenon is called imaging.

Without compensating for pathlength, the soundstage will be clumped to the left side of the vehicle. This detracts from the realism of the performance. The closer you sit to the speakers in the door, the worse the image pulls to the left.

It should be noted that many people prefer to be immersed in the middle of their music experience. If you prefer a “club” sound, your installer can deliver that with the addition of rear speakers and a modified system calibration process.

System Presets

Many digital signal processors allow for quick access to presets. If your car is set up for a single-seat tune, your installer may create a second preset that removes the signal delay and changes the way the system is equalized. They may also create a preset that provides that immersive club-like sound. This type of calibration can be great if there are passengers in the rear of the vehicle who want to enjoy the music.

Depending on the processor, presets can be loaded using simple analog switches, with a dedicated remote control or with a computerized system controller. The selection method depends on the processor you and your product specialist agree to for your system.

Enjoy Great Sound from Your Car Stereo

If you have an existing aftermarket car audio system or are planning an upgrade in the near future, ask your local specialty mobile enhancement retailer about how adding a DSP and having it professionally calibrated can improve the performance of the system. Few upgrades offer a more dramatic and beneficial improvement to the realism and detail of a mobile audio 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.