Did you know that you can get great sound in your car or truck using your factory radio as the source? Gone are the days when upgrading your audio system meant swapping in a new receiver. Today, climate controls, vehicle configuration and more are part of the original radio and display, so changes are nearly impossible. Don’t fret: The latest integration modules on the market make getting great sound easy. Keep reading to find out how.

Keep Your Factory Radio

Fewer and fewer cars today have radios that only play music. They show backup camera images or include navigation, and many offer voice recognition systems to make communication safe and easy while you drive. But what are audio enthusiasts to do when they want great sound in their vehicles? Companies like iDatalink, PAC, NAV-TV and more have developed interfaces that extract an audio signal from the factory stereo system and let us connect new amplifiers and speakers with no hassles at all.

How Modern Factory Audio Systems Work

In the good old days, factory audio systems included a radio, a simple analog amplifier and speakers. If you had a luxury vehicle, the manufacturer may have opted to include a subwoofer for a little more (but still not enough) bass. The radio was a simple affair with a tuner, CD player, auxiliary input and maybe a USB port and satellite radio connection. The output of the radio either powered the speakers in the car directly or fed a signal to a small amplifier.

Modern audio systems work differently. The source unit is similar, though USB is standard now and navigation systems and smartphone interfaces (like Apple CarPlay and Android Audio) are becoming standard, too. Where things differ a great deal is in the amplifier. The source unit sends an audio signal to the amp, sometimes as a fixed-level analog signal, but more often as a digital signal. The amplifier now includes multiple channels of amplification, plus advanced digital signal processing and the volume control circuitry for the system. In short, the radio can’t work without the amp and vice versa.

Getting Great Sound from a Ford F-150

Let’s look at three common upgrades that mobile electronics retailers across the nation perform every day. Since 2009, the Ford F-150 has come equipped with an amplifier in the back of the truck that includes the master volume control for the system as well as equalization and crossovers for the speakers. Upgrading this popular vehicle required summing audio signals coming out of the amp back together and removing signal processing.

PAC, a division of AAMP Global, offers a product called the AmpPRO 4 AP4-FD11 that works with these vehicles. The AP4-FD11 interface contains two important components. First, an audio processor takes the fixed-level audio signal from the factory radio and feeds that to high-quality preamp outputs that will connect to a new amplifier. The second part of the module is a CAN network interface that monitors communication between the factory radio and amplifier. When the network interface detects audio-related messages like bass and treble adjustments or volume level changes, it routes appropriate commands to the audio processor and adjusts the output. In essence, the AP4-FD11 adds preamp outputs to an aftermarket radio.

The AP4-FD11 is compatible with late-model Ford F-150, Flex, Fusion and Taurus, and Lincoln MKS, MKT, MKX, MKZ and Navigator vehicles. A T-harness is included with the FD11 to make the installation easier for your installer.

Chrysler 300 Audio Upgrade Solutions

Another popular audio system upgrade interface is the iDatalink Maestro DSR1. Automotive Data Solutions partnered with the audio experts at Rockford Fosgate to develop this interface and tuning solution. ADS are experts in the field of CAN communication protocols, thanks to their experience with remote car starter integration modules.

ADS combined this expertise with the Rockford 3-Sixty digital signal processor to create a unique audio interface solution that includes powerful system tuning features. The 3.Sixty DSP includes adjustable slope crossovers, 31-bands of paragraphic equalization for each of the eight output channels and signal delay for speaker time alignment. In the right hands and with the right speakers and amplifiers, the DSR1 can be the heart of an impressive audio upgrade solution.

Chevy Silverado Head Unit Interface

NAV-TV has created an impressive solution that is compatible with Chevy, GMC and Cadillac vehicles with the MyLink and Cue-equipped 4-inch (IO4) and 8-inch (IO5/IO6) source units. This interface connects to the MOST (Media Oriented System Transport) digital signal that runs from the factory radio to the amplifier in these vehicles to extract six channels of full-bandwidth audio that is free from equalization or signal delay.

The M650-GM interface retains OnStar functionality, door chimes, Bluetooth communication and all audio functions like volume, bass, treble, balance and fader. T-harnesses are available for a variety of vehicles to make the installation neat and tidy.

Upgraded Amplifiers and Speakers for Better Sound

Even when you see a branded audio system like Bose, JBL, Harman-Kardon or Sony, automakers still take shortcuts with the quality of speakers they use in factory audio systems and, of course, the systems never seem to have enough power. Once an interface is installed to extract a usable audio signal from your car or truck, your installer can integrate your choice of speakers to create smooth and detailed sound with dramatically improved clarity. Your salesperson will help you pick the right amplifier to create a system that will play at the volume levels you want without distorting or sounding muddy. If you don’t have a subwoofer, dozens of options are available to improve the low-frequency performance of your sound system to make everything more lifelike and enjoyable.

Visit your local mobile enhancement retailer today to find out how your factory radio can become a key component in an amazing audio system that rivals the best concert halls and studios in the world.
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.

One product that most car audio retailers offer that can benefit anyone with a car, truck or SUV is sound deadener. If your vehicle is noisy inside, gets hot quickly or people have trouble hearing you during hands-free phone calls, applying sound deadening can help dramatically. In this article, we’ll explain how sound deadening works and talk about the key benefits of adding damping material to your car, truck or SUV.

What is Sound Deadener?

If you have ever had the opportunity to look under the carpet or trim panels inside your car or truck, you may have seen patches of rubber or strips of butyl adhered to the body panels. The addition of this material by the automobile manufacturer adds mass to the metal panel. This added mass makes it harder for noise outside the vehicle to vibrate the panel and transfer noise to the interior of the vehicle.

Aftermarket sound deadening products work the same way. Most sound deadening is sold in sheets or rolls. The material is very dense and has one surface that includes a strong adhesive. Your installer can apply the material to flat metal surfaces like the doors, floor, roof, firewall, rear fenders and trunk of your vehicle.

Many damping materials like Dynamat Xtreme, Stinger RoadKill Expert, Wirez Premium Sound Deadening and Hushmat Ultra include a layer of aluminum on top of the flexible base layer. This aluminum adds strength to the damping material and allows it to span openings in door panels.

Some damping materials include a layer of closed-cell foam on top of the aluminum layer. Focal BAM and SoundSkins Pro are two common examples of damping materials with foam. Wirez, Dynamat and several other companies offer foam on its own as another option. This foam layer helps to reduce vibrations and rattles from objects touching the damping material. Under floors, it can prevent wire harnesses and cabling from buzzing. In doors, it prevents the rods that activate the door release mechanism and locks from rattling.

Another option for sound deadening is a spray-on solution. Cascade Audio Quiet Kote, Boom Mat Spray-On and bedliners like Line-X are a great way to add mass to flat metal surfaces.

Sound Damping Materials Make Your Vehicle Quieter

Several years ago, we took part in a test of the noise reduction capabilities of sound deadening material. The vehicle in question was a 2007 Jeep Grand Cherokee SRT with the 6.1-liter Hemi. The test started with three baseline measurements of the noise inside the vehicle. We took SPL measurements with the vehicle at idle and cruising at 40 miles per hour and 60 miles per hour. Happy with the measurements, we applied a layer of aluminum-backed damping material to the inner and outer door skins of the truck and repeated the measurements. Impressed by our findings, the last step was to treat the cargo area of the Jeep and repeat the tests once again. As you can see from the chart below, the results are impressive.

Condition Idle Cruise a 40mph Cruise at 60mph

No Deadening 88.5dB 99.0 dB 103dB

Doors 87.9dB 98.1dB 101.4dB

Doors and Cargo Area 84.7dB 94.3dB 98.7dB

Total Noise Reduction -3.8dB -4.7dB -4.3dB

Had we chosen a vehicle that came from the factory without a moderate amount of sound damping, the results would have been even more impressive.

How a Quieter Interior Improves Your Sound System

If you look at any of the sound deadening manufacturers’ websites, it will quickly become apparent that they all claim that adding sound deadening will improve the performance of your sound system. This is absolutely true and it helps in two unique and different ways.

First, by simply reducing the background noise in your car or truck, you improve the effective signal-to-noise ratio of your stereo. What does this mean? Having less background noise makes it easier for you to hear the quiet parts of your music. Imagine if you were listening to a track at a volume level of 100dB. If you have background noise level of 95 dB, any portion of the song that is around the 95dB level will have to battle with the background noise to be heard. If you can reduce the noise level in your car to 90 dB, you can hear more of your music.

The second and perhaps the most significant benefit of sound deadening is to improve the effectiveness of the speakers in your vehicle. In most cases, the doors of your car, truck or SUV have a hole in the inner skin for the speaker, and access holes for the window regulator, door handle and locking mechanism. A speaker produces an equal amount of sound from the front of its cone as from the back. If these two sound sources mix, they cancel each other out. This cancellation happens most often in lower frequencies, say below 300 Hz.

If you were to compare the in-car frequency response of a speaker mounted in the factory door location to that of a vehicle where a layer of sound deadening has been applied to the inner surface of the door, you would see a dramatic increase in bass output.

The graph below shows this very test in that 2007 Jeep Grand Cherokee. The effective output from the factory-installed 6×9 woofer increased by a jaw-dropping 8dB at 240Hz. The gains were visible for all frequencies below about 400Hz, which was, in this application, likely the upper crossover frequency of the speaker.

Another cool new product designed to help improve the performance of your sound system is Stinger’s RoadKill Fast Rings. These rings mount around the face of your door or rear parcel shelf speakers and seal up against the trim panel. The concept is that they help to channel all the sound from your speaker into the interior of the vehicle, rather than allowing it to bounce around inside the door. The rings also help reduce panel vibrations for better sound performance.

Sound Deadening Can Make Your Vehicle More Comfortable

If you watch TV shows like “Detroit Muscle,” “Truck Tech” or “Overhaulin’,” you’ve undoubtedly seen the guys apply a thorough layer of sound deadening material to the floor of some of the coolest hot rods ever. Not only do these materials help keep your vehicle quiet, but they also help block heat from the road, engine, transmission and exhaust from heating up the interior of your vehicle. Dynaliner from Dynamic Control of North America, D-Mat from Design Engineering and the aptly named Heat Barrier from Thermo-Tec are specifically designed to prevent heat transfer into the interior of your vehicle.

What to Look For When Buying Sound Deadener

Most shops latch onto a particular brand of sound deadening material that they find effective and reliable. In most cases, you can trust their choice. If you want to get picky, the most important aspect of choosing a high-quality damping material is to select one that will stay adhered to your vehicle.

There are two common problems that occur with damping materials. First, they simply may not have a strong adhesive or they require extensive surface preparation to stay adhered to a panel. Some damping materials will stick to slightly dusty surfaces without any problems. The second and more important concern is that the material itself is thermally stable. You don’t want the deadening to peel off when it gets hot in the summer. We’ve heard of many cases where vehicle carpets and headliners have needed to be replaced because damping materials turned to a liquid and contaminated them.

Install Comfort in Your Vehicle Today

If you want your car doors to close with a thud instead of sounding tinny, if you want to reduce the road and exhaust noise in your car or you want to improve the performance of your hands-free phone system, drop by your local mobile electronics specialist retailer and ask about having sound deadening installed in your vehicle. We know that you will be thoroughly impressed with the improvement.

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.

Signal processing is nothing new to car audio. In the ’80s we had stand-alone equalizers, crossovers and even phase-shifting devices — all designed to help your installer make your car audio system sound better. Lately, the focus in audio signal processing has shifted from analog to the digital domain. There are now dozens of stand-alone digital signal processors available and even more amplifiers with integrated DSP technology. Let’s take a look at why you may want to include or add a digital signal processor to your audio system.

What Does a DSP Do?

In a nutshell, a DSP uses a microcontroller that is designed specifically to manipulate audio signals in the digital domain. Pretty much all of the DSP devices on the market include crossovers, equalizers and signal delay features that we can use to optimize the performance of your sound system.

How Do I Know if I Need a DSP?

If you have an amplifier in your car audio system, then your stereo can benefit from a digital signal processor. All cars, trucks, SUVs, motorcycles, boats and even ATVs have reflections and resonances that change the sound we hear from the speakers. Listening to a speaker in a showroom is a very different experience from hearing that same speaker in a car or truck. Why? The acoustics of the environment are different.

Car Audio System Equalization

At the simplest level, a DSP can be considered a glorified yet extremely precise tone control. When you combine the features of a processor with measurements from a real-time analyzer, a properly trained technician can dramatically improve the tonal balance and accuracy of your audio system. Vocals and instruments will sound more as though you are in the presence of a live performance as opposed to listening to a recording. Expert technicians can use stereo equalization to improve the staging and imaging characteristics of your sound system, helping to increase the realism of the listening experience further.

The Importance of Accurate Crossovers

No single speaker can accurately cover the entire audible frequency range and produce adequate output to create an enjoyable listening experience. As such, car audio systems are made up of multiple speakers, each designed to operate within a specific range of frequencies. Tweeters handle high-frequency information, typically above 3kHz. Midrange drivers handle the majority of vocals and operate between 100Hz and 3kHz. Woofers and subwoofers cover low-frequency information below 100Hz. The suitability of a driver for a specific frequency range depends on its size and design.

When we design an audio system, ideally we can dedicate an amplifier channel to each speaker. In the three-way system above, we could use a five- or six-channel amplifier to power the woofer(s), midrange speakers and tweeters. The crossover functions built into a DSP handle separating the audio signal into frequency bands that are appropriate for each of those speakers.

The Benefit of Signal Delay

Let’s continue with our three-way system example. In many systems, the tweeters are mounted at the top of the door, in the sail panel, in the dash or on the A-pillar. Midrange drivers in a system like that are typically 6.5 inches in diameter and are installed in the factory door location. Finally, woofers typically require an enclosure and are mounted in the trunk, cargo area or under the rear seat of a pickup truck. The distance between the listener and each speaker is different, as is the difference between the left and right speakers. These pathlength differences result in us hearing the closest speaker first, which makes our minds think that that is the source of the majority of what we are hearing.

The signal delay capabilities of a DSP allow the technician who is tuning the system to delay the signal going to the closest speakers, so that sound from all speakers arrives at the listening position simultaneously. When executed properly, the music in the vehicle will appear to come from a space between the speakers, rather than from the speakers themselves. If your speakers are installed in optimal locations, that virtual soundstage should appear to span the width of the windshield and place each performer and instrument accurately within this soundstage.

What Else Can a DSP Do?

Most signal processors on the market include the ability to store multiple system configurations. If you want a tune for a single-seat listening position, then another for when you have friends in your vehicle, the tuning technician can create those. If you have a convertible, you may want a separate audio system configuration for use when the top is down.

Many processors have multiple inputs, and many include Bluetooth streaming options as an additional audio source. If you have a factory-installed source unit but want the option to stream music from a media player or smartphone, your installer can configure the system with multiple presets, each with a dedicated signal source.

Are Digital Signal Processors Expensive?

Well, yes and no. Good quality processors start around $400 plus installation and require at least an hour to configure in most vehicles. If you have a complex multi-channel system, you may need a DSP with more input and output channels and additional time to configure the system in your vehicle.

Regarding improvements to an audio system, investing $600 to $1,000 into a processor will yield performance gains that far exceed a similar investment in better speakers, amplifiers or subwoofers. If you already have a great audio system, adding a DSP and having the system tuned by a professional will improve every aspect of its performance.

Experience A Digital Signal Processor Today

If you are planning an audio system upgrade or you already have a system in your vehicle, drop by your nearest specialist mobile enhancement retailer and ask if they have a digital signal processor on display or in a demo vehicle that you can audition. Some shops will even have presets configured to demonstrate how each step of the tuning process will improve the performance of your sound system. Once you hear what a DSP can do, it’s hard not to want to buy one!

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 are like most people, you may think that your local car stereo shop specializes in custom audio systems, speaker replacements and, if they have marketed themselves well, remote car starter installations. The reality is, many mobile enhancement retailers offer a variety of automotive enhancement services that extend well beyond audio system sales and service. Let’s have a look at some of the service options that don’t get talked about as often. (Editor’s note: Not all of these services are available at every mobile enhancement retailer.)

Automotive Enhancement Services

The following items are offered in no particular order. Before you head to your local retailer, you may want to give them a call or send an e-mail to confirm that they provide the service you seek.

1. Parking Alert Systems

Many new cars and trucks come from the dealership with advanced collision avoidance technologies. The most basic is a rear-vision camera system or parking sensor system that can alert you to the presence of an object or person while maneuvering your vehicle. If your vehicle doesn’t have a backup camera or parking sensors, a system can be added quite easily.

2. Blind-spot Monitoring Systems

In the same vein as the parking sensors, an aftermarket blind-spot monitoring system will alert you to the presence of a vehicle or object beside or just behind yours. When an object enters this space, a small indicator will illuminate to alert you to an object in your blind spot. If you activate the turn signal, an audible warning will be produced to let you know that someone is there.

3. Heated Seat Systems

If your car, truck or SUV didn’t come with heated seats, don’t fret. High-quality seat heating elements can be added to most vehicles to make your trips a lot more comfortable when it’s cold out. If you have a bad back, a little extra warmth may the ticket to making your drive more comfortable. Most heated seat kits offer high and low settings, but you can often opt for systems with variable settings.

4. Upholstery Upgrades

If you have an older vehicle or are interested in changing the look of your interior, your local mobile electronics specialist retailer can provide you with a complete custom interior. Companies like Katzkin, Leatherseats.com and Roadwire offer vehicle-specific seating upholstery in a variety of colors and patterns, including your choice of thread color. They can often embroider a logo into the upholstery if you wish. Many shops can also swap out the carpet in your vehicle with a new custom-molded piece in a variety of colors to complete the transformation.

5. Power Windows

Did you know that you can add power windows to a vehicle that has manual crank-style windows? There are two options to achieve this upgrade. Ideally, your local retailer can swap in a motorized window regulator (lift mechanism) that is a direct fit from the factory. This option won’t be cheap but it offers the best performance and longevity. If the cost or availability of the factory system rules out that option, companies like SPAL offer universal motorization kits that include control switches. Your shop can integrate your power windows (factory or aftermarket) into your remote starter, security system or keyless entry system to allow the windows (or even your sunroof) to be opened or closed remotely.

6. Fog and Auxiliary Lighting

Who better to install aftermarket lighting than someone who specializes in automotive electrical systems? From a set of OEM-style fog or driving lights to high-power bumper or roof-mounted light bars, your local mobile electronics specialist can install and wire the system so it’s secure and reliable.

7. Emergency and Signal Lighting

If you have a work truck, talk to your local mobile electronics specialist about installing high-output emergency lighting. From beacons and light bars to surface-mount lighting, strobes, sirens and scene lighting, an automotive electrical expert is adept at integrating these systems into your vehicle safely and reliably.

8. Cruise Control

A variety of new vehicles are still available without cruise control. Whether you have a classic car with a carburetor, a new vehicle with drive-by-wire throttle or something in between, aftermarket cruise control solutions are available to make your next long-distance trip a lot more comfortable.

9. Truck Accessories

Are you in the market for a set of side-steps, a new toolbox for the truck bed, a new tonneau cover or an off-road-ready grille guard? Drop by your local mobile enhancement retailer. In addition to being experts at automotive electrical systems, most shops have the tools and experience required to install a variety of truck accessories.

10. Vehicle Tracking Systems

If you want to know where your vehicle or fleet of vehicles is at all times, a GPS-based tracking system is a perfect solution. These products can monitor a single vehicle and send you an alert when it moves, or they can log the location of dozens or hundreds of trucks, all at the same time. GPS tracking systems have been proven to cut down on wasted time and reduce the potential for accidents by altering driving behavior. Tracking systems are also available for powersports vehicles and construction equipment.

11. Power Trunk Release

Almost any car stereo shop can add an actuator to a cable-operated power trunk to integrate it into a keyless entry, remote start or security system. They can even add a switch to your dash, center console or glove box to pop the truck easily from inside the vehicle. Why stop with the trunk? How about a power fuel-filler door release?

12. Electrical Repairs

Do you have a power window that won’t roll down, a door that doesn’t lock when you press the button on your remote, or an intermittent instrument cluster? The advanced troubleshooting experience that most mobile electronics technicians possess far exceeds that of some dealership service centers. If there is something electrical or electronic not working on your vehicle, drop by and see if they can help.

13. Custom Fabrication Products

Not every fabrication project needs to be about an audio system. If you need a mobile office complete with 120 VAC outlets and mobile Internet in your SUV or van, that’s an easy task. What about building custom door panels and a center console for a custom or classic car restoration? Many mobile electronics shops around the country specialize in custom interior fabrication.

14. Radar Detector and Laser Countermeasure Systems

If you live in a state or province that allows the use of radar detectors, the team at your local car stereo shop is far and away the best choice to integrate a premium system into your vehicle. Custom installed radar detectors and laser defense systems provide early warning against police radar and can delay laser measurement devices from obtaining a speed reading.

15. Detailing and Paint Protection

Are there scratches or swirl marks in your paint finish? Having your vehicle professionally detailed can make it genuinely look better than new. There are several premium paint protection products available that can help maintain the finish of your vehicle. Ceramic coatings and paint protection film will help keep your car, truck or SUV looking like new.

16. Window Tinting

Having the windows of your vehicle tinted does a lot more than simply change the style of your vehicle. Window films block almost all of the ultraviolet energy from the sun to protect the occupants from accelerated skin aging. Premium films offer infrared rejection properties that help to keep the interior of your vehicle cooler. Window tint can also make your vehicle safer. If you get into an accident, the resulting tiny pieces of glass will remain adhered to the film rather than flying across the vehicle. Finally, window tint can help to reduce crimes of opportunity. If someone can’t see the contents of your vehicle, there is less reason for them to break in.

17. Wheel and Tire Upgrades

Many mobile enhancement retailers offer a variety of wheel and tire packages for cars, trucks and SUVs. In many cases, you can have the products you choose installed in a day or two. Nothing changes the styling of a vehicle more than a new set of wheels. Tires are the No. 1 safety item on your vehicle — they are the only thing keeping you connected to the road.

18. Premium Floor Mats

Many retailers offer automotive accessories like floor mats. One of the most popular brands in this category is WeatherTech. Their premium Floor Liner solution features a high-quality protective mat that is molded to the floor of your vehicle. The mat extends up the firewall and the center console to protect your carpet from damage, dirt and salt stains. WeatherTech also offers side window deflectors, mud flaps, bug deflectors and much more. Even if your local retailer doesn’t carry the WeatherTech brand, they should be able to source a solution to keep your vehicle looking great.

19. Boat, Motorcycle and Powersport Vehicle Audio Upgrades

Just because it’s called a car stereo shop doesn’t mean that its technicians aren’t adept at working on all sorts of mobile audio systems. Marine audio upgrades are a great way to make your time on the water even more enjoyable. Cruiser-class motorcycles are even more fun when you have an audio system that sounds great. If you want music on your side-by-side, ATV or even a snowmobile, they should be able to handle that as well.

20. Performance Parts

Are you looking for a set of lowering springs, a computer programmer or maybe a supercharger or turbo kit? Many mobile electronics retailers have technicians available to enhance the performance of your vehicle. A bolt-on exhaust, cold-air intake, high-flow air filter or throttle body spacer can provide your vehicle with a little extra power and may improve your gas mileage at the same time.

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 creating an audio system that sounds amazing, incorporating a digital signal processor into the system gives your installer the tools required to compensate for the majority of the limitations that vehicles impose. To maximize the benefit, a digital signal processor system design needs to take the features and benefits of a processor into consideration. In this article, we are going to explain some of the key differences between a system with and without a digital signal processor.

What is a Digital Signal Processor?

A digital signal processor, also called a DSP, is an audio processor that uses a microcomputer to make adjustments to a signal in the digital domain. In a stand-alone processor, the audio signal from the source unit is converted to a digital data stream using an analog-to-digital converter. Once in the digital domain, the processor can equalize, filter and even delay the signal. Most processors have six or more output channels to provide us with the ability to send different signals to dedicated amplifier channels. Each channel has a digital-to-analog converter that provides a conventional analog audio output.

Digital signal processors offer many benefits over their analog brethren. All the adjustments are handled in the digital domain, making the system impervious to errors because of differing passive electronic component values. The range of adjustability is much greater in a DSP compared to an analog processor, and because all the calculations are based on mathematical equations, the results are more accurate and repeatable. Such functions as signal delay can be performed much more easily in the digital domain than by using analog components.

Speaker Selection for DSP-based Audio Systems

Your choice of speakers and subwoofers is independent of the presence of a signal processor. The criteria for accuracy, clarity and output capability doesn’t change at all. What will change is whether or not you need passive crossover networks.

The job of a passive crossover is to split the audio signal coming from your amplifier into frequency bands that are suitable for the woofer and tweeter in your speaker set. It should go without saying that the tweeter won’t be able to reproduce mid-bass and midrange information accurately, and the woofer can’t handle high-frequency information. Passive crossover networks use a network of capacitors, inductors and resistors to split up the signal and send it to the appropriate driver.

To this point, we have been talking about component speakers. We can certainly build an amazing audio system that uses coaxial-style speakers. Coax speakers are very common when a speaker location in the dash can accommodate a four-inch driver, and many people choose coaxial speakers for the rear locations in their vehicles as well.

When we design an audio system that will be using a digital signal processor, we can use that processor to divide the audio signal before it is sent to an amplifier. The drawback is that you need additional amplifier channels. The benefit is that we have complete control over the crossover slope and frequency for each driver. This flexibility to adjust the interaction between drivers in adjacent frequency bands allows us to ensure that the output of both drivers sums accurately where they overlap. Done correctly, the transition from one to the other is smoother.

Speaker Placement Considerations

In most cases, we install upgraded speakers in factory locations in the doors. The tweeter is often placed at the top of the door, or in the dash. Depending on your vehicle, this may put the tweeter closer to the listening position, or farther away. Another consideration of installing an audio system in a vehicle is that we sit much closer to the left side of the car than the right. This means that the left-side speakers are perceived as being louder, and we hear the signal from them before we hear the one created by the right-side speakers. The result is a soundstage that is clumped to the left side of the vehicle.

All digital signal processors include the ability to apply a delay to the signal output from each channel. We can use this delay feature, along with some simple calculations, to allow you, the listener, to hear the output of both the left and right speaker at the same time. The effect is much like listening to a high-end home audio system where you sit equidistant from each speaker. Executed properly, your music will appear to come from a virtual soundstage that spans beyond the width of your windshield.

With some additional tuning, we can adjust the arrival time of the entire front stage to compensate for the distance to a subwoofer. When adjusted properly, the sound from the subwoofer will appear to come from the front of the vehicle, assuming you are using premium quality, low-distortion subwoofer.

Digital Signal Processor System Design Amplifiers

We mentioned that sound systems that are designed using a digital signal processor often require additional amplifier channels. Most manufacturers offer four-, five- and six-channel amplifiers, and several even have eight-channel amps. These multi-channel amps are ideal for actively filtered audio systems.

In the simplest of systems, we can use a five-channel amp with a digital signal processor to power a set of tweeters, a set of midrange drivers and a subwoofer. For more complex systems, you may want dedicate midrange drivers on the dash and mid-bass drivers in the door, so you’ll need another pair of channels. If you like having rear speakers, tack on another pair of channels. You may find it ideal to combine a six- or eight-channel amplifier with a dedicated subwoofer amplifier to achieve the correct number of channels and precisely the amount of power you want.

System Equalization

Another huge benefit of using a DSP in the system is that it gives us the ability to equalize the signal going to each speaker to compensate for reflections and resonances in the vehicle. Speakers have different response curves at different angles. As a result, a speaker will seem to sound different depending on where it is installed.

System Flexibility

Another benefit of building a system that includes a digital signal processor is the ability to factor multiple configurations into the design. Many processors include multiple presets that can be accessed using an optional remote control or a simple switch. We could configure one preset to provide the driver with excellent imaging and a second configuration designed to be used when there are multiple people in the car. This second option would remove some of the signal delays. The accuracy and placement of the soundstage would suffer somewhat for the driver but improve dramatically for the passenger.

If you are designing an audio system upgrade from scratch, talk to your local car stereo shop about including a digital signal processor in the system and be sure to include an hour or two of labor in the quote for tuning the system once it’s installed. If you already have an upgraded system, drop into your local mobile enhancement retailer and ask them to demonstrate the benefits of a digital signal processor. When configured properly, a DSP can make your existing audio equipment sound better. We know you will be impressed!

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.