More Advanced Sound Quality Concepts

Although the four sound quality concepts discussed above are the most fundamental, there are a few other SQ attributes that are also important:
Timbre
Tonal accuracy
Staging and imaging

Timbre

Timbre refers to a system’s ability to recreate the sound of an instrument as it was originally intended to be heard. An acoustic guitar is usually a good test for this because most people have heard an acoustic guitar. Does the sound have that warm, slightly resonant quality that the instrument is known for, or does it merely sound like a low-resolution reproduction of that signature sound? In other words, does a system reproduce the true timbre of an instrument or a poor imitation of it?

And this doesn’t just apply to acoustic instruments. Although some would argue that it’s not possible to know the true sound of a Roland 808, a popular synthesizer for creating the deep bass sound in many rap recordings, the producer had a sound in mind when he cut the track. How close a system comes to reproducing that sound reflects how accurate it is in timbre.

Tonal accuracy

Tonal accuracy is used to describe how faithful a system is in general to the original recording. It can apply to instruments as well as vocals. The more accurate the system is while playing a good recording, the more you feel as if you are there, listening to a live performance as opposed to a recording.

Tonal accuracy can also apply to the ambiance in a recording. Ambiance refers to the space in which a recording is made. Most modern recordings are made in a sort of vacuum, with individual instruments recorded separately or, in the case of some rap music, the individual parts are sampled from other recordings. But many older recordings, some modern ones, and almost all live albums capture the environment in which the performance was recorded. In fact, certain recording studios and performance spaces are known and revered for their sound, which give a recording or performance a specific ambiance.

Think of timbre and tonal accuracy as the reproduction of how close you     get to the actual performance or how the producer intended for it to sound. Whether it’s the sound of Miles Davis’s trumpet, Jimmy Page’s guitar, a Dr. Dre beat, or the ambiance of Carnegie Hall, whether a system can reproduce it the way it went down in a studio or concert hall determines the difference between a good system and a great one.

Staying and imaging

Staging and imaging are related concepts that go back to the heyday of stereo, and therefore don’t always apply to modern music. The basic idea is that when you’re listening to a stereo recording, the system should recreate the illusion of the stage on which the performance is occurring, and you should be able to pinpoint the sonic image of the individual performers and instruments within the stage. (see Figure 3-2)

Think about the example of a basic rock band that includes a singer, guitarist, bass player, and drummer. In this instance, you should be able to close your eyes and picture the singer at the center of the stage, the guitarist to the right, the bass player on the left, and the drummer center and behind the singer. Keep in mind that this is an ideal that sound quality systems should approach if not achieve. With rap and many pop-music recordings, the vocalist will be centered, but the concept of a band playing on a stage doesn’t exactly apply.

also see Level matching starts with the head : Audio Car

If you ever go to a sound-off competition or read reviews in car audio magazines, you may hear judges or writers mention something like, “The stage was a bit low and imaging was fuzzy.” What this means is that the stage in the car was below, say, dash level and the listener was unable to clearly distinguish the individual performers within the stage. Ideally, the sound stage in a car audio system should be high, wide, and deep, and imaging should be as pin¬point as possible. In a vehicle, sonic images are often pulled to one or the other side (or both) because speakers are usually mounted in a car’s doors.

Speaker placement has a dramatic effect on staging and imaging, and hardcore enthusiasts often go to great lengths to position their speakers for the best possible results. This includes rebuilding door panels or kick panels to better position speakers. Some have even build elaborate mechanisms to mount speakers in or raise them above the dash in order to achieve better staging and imaging.

more see Keeping It Quiet for Reproducing Great Audio

Finally, no discussion of sound quality would be complete without mentioning interior acoustics. A car’s interior is a huge part of the audio system and plays a dramatic role in a system’s response. Beyond the shape and size of a car’s interior, it also has reflective surfaces such as glass and absorptive materials such as upholstery. And almost every car interior is different. Therefore, even if you install the exact same components in your Toyota Camry that your friend has in his Chrysler 300C, the systems will sound very different.

Figure 3-2:
An example of staging and imaging of a car audio system.
Courtesy of IASCA

What a USB in the Dash !

An MP3 player syncs to Ford’s Sync via a USB port, which has become as common as clover on all sorts of electronic products. Originally found on computers, USB (which stands for Universal Serial Bus) has quickly migrated to all sorts of electronics products as a quick way to transfer information. Now car audio systems, both aftermarket and stock, are beginning to sport USB ports.

Another way in for the iPod

One of the primary applications for USB drives in cars has been as a way to integrate an iPod. Because it’s also the way an iPod syncs to your computer, a USB connection provides the best possible sound quality as well as slightly faster access to music on an iPod. Consequently, most of the major car audio manufacturers that offer iPod integration use a USB connection to dock an iPod and transfer information to and from the device.

Thumb drives

Car audio head units have also begun to sprout USB drives on their front panels (see Figure 7-7). This allows easy and quick access to digital music files loaded on a USB thumb drive, a small flash-memory device that is about the size of a person’s thumb. Depending on the capacity of the USB drive (which is measured in megabytes or gigabytes, with higher being better), it’s possible to store dozens of songs on a drive small enough to fit in your pocket.

Figure 7-7: A Kenwood head unit with a USB port and a thumb drive attached.

Courtesy of Kenwood

Yet another way to carry MP3 files on the road is with Secure Digital (SD) and MuItiMediaCards (MMC). You’re probably familiar with these if you own a digital camera because many use the removable cards to store pictures. As with USB drives, the larger the capacity of the SD or MMC cards, the more tunes you can store on it, and the more expensive the card is. And because they are even smaller than USB drives, SD and MMC cards are a convenient way to carry dozens of MP3s on the road.

SD and MMC cards actually predate the presence of USB drives in the car audio world by several years, and SD cards have proven to be the dominant format. A few manufacturers — including Clarion, Dual, and Jensen — now offer SD card slots on their head units, typically behind a fold-down faceplate. And Audi, Mercedes, and Honda offer SD card slots in the dash on the OEM side.

Hard Disc Drives: Burn, Baby, Burn

Higher-capacity iPods and similar MP3 players are simply data storage devices with functions, that allow you to access your tunes, whereas USB drives and SD cards are simply flash drives for temporarily storing your music files. But chances are you also store all of your tunes on your com¬puter’s hard drive and transfer it over to a hard-disc MP3 player or flash- memory device.

So why not install a hard-disc drive (HDD) into your car and just dump all of your tunes on it? Well, several car audio manufacturers had the same idea a few years ago, about the time the whole iPod craze kicked in. But by that time, most people didn’t want to go through the hassle of downloading their music to a hard drive in the car, which involved the tedious task of ripping songs from CDs one disc at a time, when they could have all the music on their iPod or other MP3 player. Subsequently, HDD head units never really caught on. There are still some around (like the Alpine HDA-5460 shown in Figure 7-8), and you can probably get a killer deal on one.

Some high-end head units these days use an HDD for the mapping database and operating system for GPS navigation because it offers fast access time. Pioneer and Eclipse (see Figure 7-9) also offer nav-based head units with an HDD, with part of the disc space used for storing music. 

Figure 7-8:

Alpine's HAD-5460 contains a hard-disc drive for storing music files.

Courtesy of Alpine Electronics

Figure 7-9:

The Eclipse AVN5495 has a hard- disc drive that’s used for

navigation as well as storing music files.

Courtesy of Eclipse Electronics

The HDD has also found a home in some stock car audio systems. Cars from Cadillac, Chrysler, Dodge, Infiniti, and Lexus offer in-dash HDDs for storing hundreds of digital music files.

MP3 Player Invasion of the Apple’s iPod

Apple’s iPod wasn’t the first MP3 player. Others were around several years before it. And it wasn’t the least expensive by a long shot. But the iPod was the MP3 player that captured millions of music lovers’ hearts and minds, music collections, and pocketbooks. The iPod quickly became a status symbol as much as a phenomenally popular product, and, in the process, it changed the way people buy, listen to, and store music.

The iPod also changed the way people access music in the car. In just a period of a few years, it’s made the CD changer virtually obsolete. Why bring a half dozen discs or more along for the ride when you can carry your entire music collection in your pocket? It didn’t take long for the consumer-electronics industry, the car audio aftermarket in particular, and even some carmakers, to respond to the growing number of iPod owners who wanted to take their iTunes on the road.

Today, there’s a billion-dollar industry based just around iPod accessories, and car accessories form a large chunk of this lucrative market. iPod integration has also become a driving force in the aftermarket car audio industry because the desire to use an iPod in the car has driven more consumers into car audio specialty shops and other car audio outlets.

Just as CD changer controls were popular features on car audio head units in the 1990s, now many heads have an auxiliary input for an iPod or even full iPod integration. Carmakers have also gotten into the act as consumer demand for pimpin’ a ride with an iPod has increased.

Today, you can access an iPod from behind the wheel in a wide variety of ways:

1. FM modulators that send a signal to a car’s FM radio
2. Aftermarket head units that have direct iPod input and controls
3. Aftermarket adaptors that can add iPod integration to factory stereos
4. Auxiliary (aux) jacks in aftermarket or stock stereo systems
5. Aftermarket amplifiers and processors with aux inputs
6. Kits available from car dealers that integrate an iPod with a factory stereo and the car’s controls

FM modulators

FM modulators have been used for years to add a CD changer to a factory stereo system, or even in aftermarket systems where a direct-connection between the head unit and the changer isn’t available. The concept is simple: 

The audio signal from the CD changer is fed into an FM modulator, which converts it to an FM signal. The head unit’s antenna lead is fed into the FM modulator and a separate antenna lead from the FM modulator — which now carries the AM and FM signals, along with that of the converted signal from the CD changer — is plugged into the head unit.

The FM modulator lets you choose an FM frequency on which to tune in the CD changer, which is usually in the 88.1 to 89.5 range. When the car’s FM receiver tunes to that frequency, which is hopefully empty, it picks up the signal from the FM modulator the way it would a regular radio station.

Wireless FM modulators that don’t have to be hard-wired into a vehicle are now available. Instead, the FM modulator simply sends a wireless signal to the FM tuner, and it’s picked up as a radio station. Wired FM modulators provide superior sound quality, however.

FM modulators offer a quick, easy, and inexpensive way to integrate an iPod into an existing car stereo, whether stock or aftermarket. A variety of after- market FM modulator products are available, ranging from simple to complex. Most will also charge your iPod at the same time. But FM modulators have two major drawbacks:

Your music will only sound as good as the best FM reception, which is way below CD quality.

If you live in or you’re passing through an urban area, it can be hard to find an empty spot on the FM dial, and even if you do, you can easily get interference from adjacent stations.

It’s a good idea to look for an FM modulator what allows you to select from a variety of FM frequencies, such as Monster Cable’s iCarPlay Wireless Plus, shown in Figure 7-1. That way, if one FM frequency is occupied or filled with static, you can tune to another one.

Testing, testing... 

Here's a good test to determine the quality of the FM modulator for your iPod (or any other MP3 player). Connect the MP3 player to the FM modulator and find a blank station on the FM dial for the signal. Then pause the iPod, turn radio all the way up, turn on the car's engine, headlights, and rev the engine and listen for noise. A high-quality FM modulator is relatively quiet, whereas a low-quality one produces more noise. 

Figure 7-1:

Monster Cable's iCarPlay Wireless Plus sends an iPod's signal to an existing car stereo.

Courtesy of Monster Cable

Aftermarket head units

Full iPod integration in an aftermarket head unit offers much better sound quality than FM modulators because the audio signal is fed directly into the head unit. And it also allows easy access to the music on the iPod through the head unit’s own controls and provides information on the head unit’s display. This way, you never have to touch your iPod after you hook it up to a head unit, which is a huge safety advantage as well as a major convenience.

But not all iPod-ready head units are created equal. Most offer basic controls that allow accessing music just as you would on an iPod: by artists, albums, songs, and playlists. And the head unit displays the corresponding info visually. One of the biggest factors you should think about when considering iPod integration is access speed.

Alpine, for example, advertises its latest-generation iPod integration products as full speed, meaning that the rate at which you can access tunes on an iPod via one of the company’s head units (see Figure 7-2) is about the same as if you were operating the iPod itself. Kenwood, Pioneer, and Clarion also offer high-speed iPod access. Plus, most head units with iPod integration also charge the device while it’s connected.

Courtesy of Alpine Bectronics

Aftermarket iPod adaptors

Leave it to the car audio aftermarket to give the people what they want.

These days, what people want is to use their iPods while they’re on the road, no matter what car they drive or whether they have an aftermarket head unit. Some people may not be willing or even able to change out their radios because of cosmetic or cost concerns or lease restrictions. That’s where innovative car audio accessory companies such as Blitzsafe, PAC, Peripheral, PIE, and Scosche have come to the rescue.

Such companies may not be household names or even have the marquee value of other large and well-known car audio brands, but they are renowned in the car audio industry for providing solutions, largely to car audio specialty dealers, that integrate aftermarket electronics into almost any kind of vehicle. In the case of iPod integration, these companies offer adaptors that tap into a vehicle’s factory wiring and electronics so that the popular music player can be added without high costs or hassles.

Scosche’s AXIPTA, for example (see Figure 7-3), fits many 2004 and up Toyota, Scion, and Lexus vehicles and allows control of an iPod from the stock head unit, which also displays all of the control and track info. Such adaptors are also non-invasive, meaning they can be taken out and the car can be returned to stock condition. 

Auxiliary inputs

Auxiliary inputs designed for plugging in a separate audio source have been around a long time, and they usually pop up like mushrooms after a rain storm when a new audio format comes on the scene. They were somewhat prevalent when CDs were still rare in car audio, for example, and people wanted to a plug a portable CD player into their car’s cassette-based head unit. A car audio system 1 put together in the late 1980s, for example, had an aux-in on the back of the head unit, into which I plugged a portable CD.

Today, many aftermarket car audio head units sport aux inputs, as do an increasing percentage of new cars. Car manufacturers have recognized this as a feature that more and more consumers want. Although most are 3.5mm miniplug jacks (see Figure 7-4), which fit the same connector that an iPod and other MP3 player use, a few use RCA-based aux inputs like those found on most car and home audio components (see Figure 7-5).

An aux-in jack is an easy and affordable way to jack an iPod (or any MP3 player or auxiliary audio source) into a car audio system, but you still have to fumble with the device to control it, which isn’t very convenient or safe while behind the wheel. And it’s not iPod-specific, which means you can plug in any outboard audio device. 

Some car audio companies that don’t make head units have also gotten in on the aux-in act. They allow an iPod or other MP3 player to be added into a system’s signal chain on an amplifier, equalizer, or some other component (see Figure 7-6).

Figure 7-6:

Blaupunkt's

GTA480

amplifier

hasanaux

input

Courtesy of Blaupunkt

Car dealer kits

BMW launched the first iPod integration application among carmakers in mid-2004, with a dealer-installed option that allowed owners of certain Bimmer models to control the device via steering-wheel audio controls. Information such as artist, album, and song can be displayed on the in-dash head unit. Since that time, fourteen more auto manufacturers have begun offering iPod integration kits. (You can see a complete and updated list at www.Apple.com/ipod/carintegration.html) The obvious advantage of this approach to iPod integration is that you can keep a factory look.

Sync and the future

As the iPod becomes more entrenched and widespread and other portable players come on the scene to challenge its dominance, look for more car-integration solutions to appear. Ford recently unveiled its Sync system, for example, which was developed in conjunction with Microsoft. It allows complete control of a portable music player via voice commands and steering-wheel switches, as well as cool features such as a “play similar” command that will automatically cull a playlist based on your music preferences.

Don't Forget for Carrying All Your Tunes

• Understanding the impact of the iPod
• Integrating an iPod into a car audio system
• Using other MP3 players
• Accessing music on a USB drive
• Discovering in-dash hard drives

Bringing lots of tunes on the road with a CD changer and lots of bulky discs is now so twentieth century. In the late 1990s, I installed a 100- disc CD changer in the trunk of one of my cars for a cross-country trip. At the time, it was the only way to bring a ton of tunes along. But I knew something was amiss when it took an hour or so just to load up the thing. I’ve since taken the mega-changer out, and now 1 can carry 10 times as many tunes on my iPod, which is one-tenth of the size.

MP3 players such as the iPod have irreversibly changed the way people carry music into the car. The advent of the MP3 has especially been a boon to mobile-music lovers because it’s now easy to take thousands of digital tunes on the road. Although disc-based head units still dominate, most now offer some way to let users have access to their large libraries of digital music files.

Today more than ever, the way you carry your music files on the road — be it with an MP3 player like the iPod, burned onto a disc, loaded on a USB drive or SD card, or even on a hard-disk drive — will determine what sort of car audio head unit or system you choose. You can even have several different portals for access to your tunes within a single car audio system. These days, the digital-music options are only limited by your imagination and budget.

In this chapter, I explore ways in which you can bring your entire music collection on the road ... without installing a dozen 100-disc CD changers in your ride. Because Apple’s iPod dominates the MP3 player market, most of the ways to integrate an MP3 player into a car stereo are iPod-specific.

But we’ll also look at other MP3-friendly portals, such as USB drives and hard-disc drives.