For decades, automobile manufacturers have installed relatively large rear speakers in their vehicles. The stereotype of a set of 6×9 speakers sitting on the parcel shelf of a Monte Carlo is as “car audio” as it gets. As the industry has evolved, the importance of rear speakers has diminished. Are rear speakers necessary? Do they offer a benefit? Are we just holding on to a bad habit? Read on to explore more about rear speakers.

Why are They So Big?

Automakers used to take advantage of the opportunity to put speakers in the rear of their vehicles because those speakers could be larger that the ones in the front of the vehicle. Consider a third-generation Camaro or Firebird. They had a set of 4×6 speakers on the dash and a set of 6×9 speakers in the rear sides. Likewise, a fourth-generation Monte Carlo had 3-1/2-inch speakers in the dash and 4×10-inch speakers on the skinny little rear deck.

In most cases, a speaker with more cone area will play louder for a given amount of power. Larger speakers are capable of producing more bass. We recently saw a factory audio system with a 9-inch door speaker, and 6x9s in a pickup truck and SUV doors are very common.

What is Our Goal?

The trend in the last decade for both factory and aftermarket car audio systems has been to recreate a live performance as realistically as possible. This shift in design has introduced us to the need for proper speaker placement and the use of larger speakers in the front of the vehicle. The use of digital signal processors to set up crossovers, signal delay and equalization for each speaker location has further improved on our ability to create what is known as a soundstage in our vehicles.

A soundstage refers to a perceived source location for our music. In a perfect world, our music would appear to come from far out in front of us and provide a good sense of width and depth, excellent focus, and realistic ambiance – just like a live performance. Automobile manufacturers have to balance cosmetic design versus optimum speaker placement, and speaker placement often loses the fight.

What is Your Goal?

How do you like to enjoy your music? Do you attend live performances? Do you listen to a two-channel system at home? Do you usually use headphones? Are you into surround sound? Your answers to these questions can help your car audio specialist retailer design a system that will sound the way you want.

If you like live performances and two-channel audio, then it’s most likely that you would enjoy a system with a soundstage that is out on the dash of the vehicle. In this application, rear speakers are not very important, and in most cases, the money saved by not purchasing and installing rear speakers at all will allow you to buy better front speakers.

If you listen to headphones, then you may want the sound from your system to wrap around you evenly. You may enjoy a system that makes you feel as if you are in the middle of the sound. An equal amount of sound will come from in front of you as behind you. In a system like this, using similar or even identical speakers in the front and back can help produce great results.

If you watch a lot of movies in surround sound, then you need to work with your retailer to decide what is right for you. In movies, the side and rear channels are usually reserved for special effects and ambiance. You may want to go without rear speakers in a mobile audio system. Very few sources include surround information, and currently there are no aftermarket surround sound reproduction solutions, although some are coming.

Are You a Purist?

In pure, raw technical terms, you want as few speakers in your system as possible. Additional sources of sound can result in interference patterns called comb filtering. An ideal system would offer full-range left and right signals, and – because we typically can’t use large speakers in our doors – a subwoofer to fill in the bottom few octaves.

The placement of the speakers can have a dramatic effect on the sound of the system. From a perspective of tonal accuracy, having the midrange speakers in the doors works well. This location typically produces a very wide soundstage. A door location does not often result in a soundstage that appears to emanate from far out in front of you. To achieve that, you may need to use a smaller midrange speaker with a tweeter in a dash or A-pillar location.

When possible, try to ensure that tweeters are mounted within 20 degrees of being on-axis to the listening position.

Who’s Back There?

Another consideration for rear speakers is whether you have passengers in the rear of the vehicle. If you have children or friends in the back, then it would serve them well to have speakers to enjoy. Yes, they will be able to hear the dash or front door speakers, but not as clearly as if they had something close by. It would not be unreasonable to design an audio system that allowed you to turn the rear speakers on and off, depending on your needs.

Rear Speakers as Rear Fill

For systems designed with a focus on the front soundstage, rear speakers are often operated at a much lower relative level than the front. Some people call this technique “rear fill.” The intent is to provide a sense of spaciousness to the listening environment. Employing rear fill speakers splits the divide between systems with or without rear speakers. The relative level of these speakers is critical. Too much can start to pull the soundstage rearward.

There is no right or wrong when it comes to a preference for the location of your soundstage. Whatever you enjoy is the right choice. Your local mobile electronics specialist retailer can work with you to design a system that sounds the way you enjoy. Drop in today and ask if they have a demo vehicle that you can audition. That’s a great way to decide what solution is best for you.

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.

Installing a mobile audio system involves much more than just hooking up some wires and driving in a few screws. Almost all vehicle manufacturers have realized that some amount of audio system tuning will dramatically improve their customers’ experience. When you decide it’s time to upgrade your factory audio system, we need to take into account any tuning that may have been done by the factory. It’s not easy, but at the same time, it’s not impossible. This article provides a brief look at what is involved in connecting a new amplifier and speakers to your factory source unit or amplifier, or as it is called, OEM integration.

It’s Not Flat

No, we aren’t talking about the Earth. One of the first steps in designing a premium audio system upgrade is to measure the electrical signal that is being sent to each of your speakers. Why? As we mentioned, more and more factory source units and amplifiers include advanced signal processing. Even some of the most basic audio systems with only four speakers have custom equalization for each speaker. Once our installers know what they are dealing with, they use that information in designing your new system.

The signal measurement process should be done before system design. If the signal is flat (no equalization), then the system design may take a different direction from when the signal is equalized. Compensating for factory equalization requires that some kind of equalizer be installed in the new system. Either way, we have to allot time to measure the acoustical response of the new system and make appropriate adjustments.

Think of this process as though your installer were a surgeon preparing to solve a medical problem for you. The surgeon will order x-rays, scans and many tests long before you’re on the operating table. Nobody wants to start work on a project without knowing what they are dealing with. Modern car audio systems are no different.

Front and Center

Automobile manufacturers strive to make all their customers happy – within a certain budget. This goal includes providing an enjoyable audio experience for everyone in the vehicle. Many mid- and high-level factory audio systems use a center channel to help create a listening experience that is enjoyable for both occupants of the front seats. Configured properly, a center channel can help create a realistic soundstage from both seating positions. Trust us when we say that some of the people who tune these factory audio systems have a lot of experience doing what they do.

When we want to upgrade the audio system in a vehicle with a center channel, we have to reverse-engineer how that speaker is functioning. Is it a mono signal that is the sum of the left and right signals? Is it an up-mixed signal that plays sounds that are not reproduced by the left and right speakers? It could also be a little bit of both. Your installer will have to do some tests to decide what is happening and how to deal with it.

Do We Undo or Up-do?

If you have a vehicle with a genuine up-mixed center channel, one of the best ways to upgrade the audio system is to leave the processing alone and add better speakers, amplifiers and signal processing. With this method, we can create a sound system that sounds amazing from both the driver and passenger seats.

The basic concept is to take the left, center and right signals; recombine any frequency filtering; then send those three signals to whatever speakers you choose for each side of the vehicle and the new center channel. Often, the new system will be a three-way speaker set in the doors and maybe the A-pillars, and a two-way system in the center. We will most certainly use a digital signal processor and/or an integration processor to do the signal filtering and tuning for the new system.

How We Undo What They Do

Several processors on the market can sum filtered channels together and undo factory equalization and time alignment. Some of these processors require manual adjustments and some work automatically with a custom setup track. After using one of these processors to provide a full bandwidth signal, we can then use digital signal processing to set up the new system and compensate for the vehicle acoustics. Just as the vehicle manufacturer chose to equalize the signal going to each speaker, we need to do this to maximize the performance of your new system.

What if We Don’t Undo What They Did?

Imagine a simple scenario: You have a car, perhaps a Nissan Altima. Even the base model audio system has equalization in this vehicle. Equalization is based on the speaker that is being used, location of the speaker and acoustic effects of the vehicle on the signal from that speaker relative to the listening position. If we change the speaker to one that is better, the factory equalization can – and most likely will – work against us. That nice new speaker may sound worse than the cheap factory speaker. After all, the manufacturer tried to make what was likely a low-quality speaker sound OK.

Trust Your Local OEM Integration Experts

When it comes time to upgrade the audio system in a fairly new vehicle, make sure you are working with a mobile electronics retailer that knows how to evaluate the existing audio system properly. If you are changing the source unit, then it’s no big deal. But if you are using the factory radio and/or amplifier, proper testing is crucial. Don’t be scared or discouraged. A well-trained retailer can transform any audio system into something truly amazing! Drop in and see what they can do for you.
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.