Advanced Car Audio Sound Quality Concepts
Although the four basic sound quality concepts (clarity, dynamic range, frequency response, and tonal balance) are the most fundamental to understand before purchasing a new car audio system, there are a few other sound quality attributes that are also important.
Timbre (pronounced "TAM-bir") 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 one. 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?
Tonal accuracy describes 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, which 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, how well 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.
Staging 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 occurred, and you should be able to pinpoint the sonic image of the individual performers and instruments within the stage.
Think about the example of a basic rock band that includes a singer, guitarist, bass player, and drummer. 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.
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 to better position speakers. Some have even built elaborate mechanisms to mount speakers in or raise them above the dash in order to achieve better staging and imaging.
Finally, no discussion of sound quality would be complete without mentioning interior acoustics. A car's interior, its reflective surfaces (such as glass), and its absorptive materials (upholstery) play a dramatic role in a system's response. And every car interior is different; 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.