As we continue our deep-dive into the functions of car audio digital signal processors, we’ve reached the topic of crossovers. Many people overlook the importance of configuring crossovers properly to achieve a smooth frequency response. Let’s take a look at what a crossover does and why your technician must set them correctly to protect your speakers.

What Is a Crossover?

All speakers, no matter their size, have limits in terms of their ability to reproduce low-frequency audio information at high levels. For small speakers like a tweeter or midrange driver, attempting to produce bass is a recipe for disaster. Crossovers are used to limit the audio information being sent to a speaker above or below a set frequency.

High-pass crossovers allow information higher than the set frequency to go to the speaker. Low-pass filters do the opposite – they pass audio information below the crossover frequency.

High-pass filters are used to prevent bass and midrange information from being sent to tweeters. Low-pass filters are used to prevent midrange and high-frequency information from being sent to a subwoofer. For midbass and midrange speakers, we combine a high- and low-pass filter to create what’s known as a bandpass filter. A bandpass filter has limited low- and high-frequency information.

Crossovers have three defining characteristics: the crossover frequency, the attenuation rate and the type of crossover response curve.

Crossover Frequency

Depending on the response curve chosen, the crossover frequency defines the -3 dB or -6 dB point for the filter. When setting crossovers between midbass woofers, midrange speakers and tweeters, we want the output to sum flat – as though there were no crossover, and we had a single speaker that would play through the entire audio range. To achieve this, we need the crossover frequencies for both speakers to be the same.

Crossover Slope

The slope describes how fast audio signals in the stop-band are attenuated. A crossover isn’t a brick wall or a switch. Say you set a high-pass crossover at 3 kHz for a tweeter. You still get output at 2.5 kHz and 2.0 kHz. The rate at which that output attenuates is the slope. The slope is described by how much the output is reduced per octave away from the crossover point. The most commonly used slopes are -12 and -24 dB/octave.

Crossover Response Options

Some companies describe the shape of the filter response using different terms – alignment, damping or simply crossover type. These options describe the behavior of the filter around the crossover point and how the output sums with an adjacent filter. This is a topic that could fill a textbook, but suffice it to say that some types work better in car audio applications than others. Your technician should know what to use to achieve the flattest response and best speaker radiation pattern around the crossover frequency.

Choosing the Right DSP

Most of the high-quality digital signal processors on the market have very flexible crossover frequency, slope and response options. Where you need to pay attention is in choosing a DSP that has enough channels for your system, and in ensuring that any channel can be configured with any type of crossover. In some cases, manufacturers link channels together. While usually acceptable for conventional systems, linking presents limits when you want to drive a center channel speaker.

Lastly, and most importantly, you want to choose a technician who has the tools (a calibrated RTA) and the training to ensure that the crossovers that he or she configures for your audio system protect speakers adequately. Of course, the system also needs to be designed using speakers that complement each other and deliver smooth sound distribution throughout the vehicle. Start with your local specialty mobile enhancement retailer. Ask to hear some of their demo vehicles. Ask what RTA they use, how long they take to configure a system, and how they ensure it’s adjusted to suit your listening preferences.

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 a fan of upgraded car audio systems, then you might have noticed that technology has made things a lot more complicated. Years ago, it was easy to upgrade your stereo. A new radio, some new speakers and maybe a subwoofer like a Bazooka Tube were all you needed to improve on the factory sound system. Since 2010 (depending on the vehicle), even mid-level OEM audio systems have been able to rival or exceed what would have been deemed an upgrade years ago. While still a long way from what creates a true audiophile-grade listening experience, the technology used to achieve impressive performance levels has made upgrading things challenging.

Why are OEM Audio Systems So Complicated?

Vehicle manufacturers are in a constant battle with the laws of physics to provide their clients with the most performance, comfort, features and fuel economy for their dollar. Smaller turbocharged engines with fuel injection have more than doubled fuel economy as compared to the big carbureted V8s from the ’60s. Blind-spot monitoring and anti-lock braking systems help us prevent accidents. When it comes to audio systems, compact Class-D amplifiers with integrated digital signal processing allow OEM audio suppliers like Harman, Bose and Panasonic to deliver impressive audio performance from a compact, lightweight package.

The technology in these audio systems not only sounds OK at low and moderate volume levels, depending on the vehicle, but can also provide realistic imaging and staging from both front seats. Until a few years ago, the car audio aftermarket couldn’t deliver the same two-seat performance without a complex and potentially costly installation.

Upgrade Your Factory Stereo with a Subwoofer

If you have a complex sound system that includes a center channel or any sort of 3D processing features, your local car stereo shop can still upgrade the system for better sound. The first step would be to add a subwoofer. Very few (if any) systems can’t benefit from better bass performance with extended low-frequency performance that a subwoofer can provide. If you are imagining a large enclosure in the trunk of your car, don’t fret. Today, most upgrades can be concealed in the spare tirewell, behind or under the rear seat in a truck, or in a trim panel in the cargo area of an SUV.

Crank the Volume with a High-Power Amplifier

If you want the system to play louder, then adding a multi-channel amplifier with an integrated digital signal processor is a good starting point. A new six-channel with DSP amp can deliver as much as 150 watts of power to the front speakers to ensure you never run out of juice when you crank up the volume. Most of these amplifiers have provisions for a subwoofer amplifier with a processed signal so your installer can tune the subwoofer once it’s added to the system.

If you’d added an amplifier and some tuning capability, then upgrading the system with new speakers is the icing on the cake in terms of getting great sound. Truly high-quality speakers include features like copper or aluminum shorting rings, copper T-yoke caps, and flat-wound voice coils to reduce distortion and improve clarity. When paired with a quality amplifier and tuned to compensate for the acoustics of your vehicle, new speakers will transform the listening experience into something truly amazing.

Factory Amplifier Replacement Interfaces

Companies like NAV-TV, Metra, PAC and mObridge offer interfaces that allow your installer to replace a factory amplifier and open up complete flexibility in terms of designing a new audio system. If you want to eliminate the signal processing that came with the factory stereo and pick your amplifiers and processors, then one of these interfaces is a perfect starting point. The interfaces work with many factory-installed audio systems that use MOST, A2B and CAN communication protocols and will typically eliminate Active Noise Control (ANC) and systems that inject engine sounds into the audio system.

Embrace Modern Car Audio Technology

Even though modern automotive infotainment systems have become exceedingly complex, your local specialist mobile enhancement retailer can take the best of what the vehicle manufacturer provided and spice it up with a subwoofer, new amplifier and better speakers. If the stereo in your car or truck doesn’t put a smile on your face, drop by a local shop and see what they can do to help!

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.

In recent years, vehicle manufacturers have turned to active noise cancellation to make the interior of new cars and trucks quieter. Using technology similar to that found in noise-canceling headphones, the perceived level of low-frequency road and wind noise can be reduced using the audio system. When it comes time to upgrade your car or truck with a subwoofer, this noise-canceling technology can wreak havoc with your upgrade if not addressed properly.

What is Active Noise Cancellation?

Active noise cancellation (ANC), also known as active noise control, reduces the perceived level of road and wind noise by creating sounds through the factory stereo that, when combined with the noise, cancel each other out. The system works using signals from a series of microphones placed around the vehicle. These signals are inverted and after appropriate processing and delays, sent to the larger speakers in the car. The audio signals produced by the speakers mix with the noise information and cancel each other out. The result is a much quieter cabin and minimal added weight compared to passive noise solutions like sound deadening. One of the first commercially available vehicles to use ANC was the 1992 Nissan Bluebird. The benefit was minimal because of the limited signal processing power available at the time.

Many modern vehicles, including the Honda Accord, Nissan Maxima, Buick LaCrosse, Cadillac XTS, Chevy Silverado and Infiniti Q60 and Q70 feature modern implementations of this technology.

This noise-canceling technology is similar to what Sony and Bose use in their noise-canceling headphones.

How Does ANC Affect a Car Audio Upgrade?

Vehicle manufacturers invest a lot of time in designing and calibrating these noise-canceling systems. If you’ve decided to upgrade your car stereo system with an amplifier, new speakers, a subwoofer or sound deadening, your installer will need to check for the presence of an ANC system. If upgrades are installed without disabling ANC, large amounts of unwanted low-frequency will be added to the system.

If you are wondering if your vehicle will be noisier with the ANC disabled, you might be right. Don’t fret. This can be fixed with the addition of carefully implemented passive sound absorption solutions. Adding sound deadening to the firewall, the fenders, the doors and the roof will dramatically reduce the amount of noise that enters the vehicle and allow your new stereo equipment to sound amazing. Adding sound deadening may produce better overall results than an ANC system as active systems are limited to only low-frequency information. The small amount of added weight is a small price to pay for the dramatic improvement in the sound of your mobile audio system.

Upgrade Your Car Stereo System Today

If you are tired of lifeless, boring sound from your car stereo, drop by a local specialty mobile enhancement retailer today and find out what they can offer in terms of an upgrade. If your vehicle has active noise cancellation, they will let you know what’s required to keep things quiet and comfortable as you drive. Don’t let a little technology stand in the way of enjoying your music with the detail, impact and clarity you want.

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.