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