There is very little room for debate about the fact that proper speaker installation is the most important factor in determining how good, or how bad, an audio system will sound. It is absolutely true that less expensive, moderate-quality speakers installed properly will sound better than even the highest quality, most expensive speakers installed poorly. However, those same high-quality speakers, when installed properly, can produce truly outstanding sound quality in an audio system, and that's what we want!
While there are hundreds of different car audio speakers available, ranging from subwoofers to tweeters, the same basic installation guidelines apply to all of them when it comes to maximizing any speaker's sound quality potential.
The mounting requirements for a subwoofer are well documented and relatively obvious. Being a large speaker that will move a lot of air necessitates that it be installed in a well-built, solid enclosure. Most installers and enthusiasts understand this fact (even though, unfortunately, they don't always install them this way).
But what about the higher-frequency speakers: the midranges and tweeters? In most installations, much less attention is paid to these speakers than to the subwoofers. In fact, many systems that do produce good low-frequency response from the subwoofers do not produce the same performance from the rest of the speakers in the system, quite often because the midrange and tweeter speakers are poorly installed, severely limiting the system's true sound quality potential. But with just a little additional effort in the installation of these speakers, the system can sound really good.
Of course, you can go to the most extreme levels for speaker installation, spending hundreds of hours on the design, fabrication and detail when building an ultra high-end system for sound quality competition, for example. But in the real world, for those of us who simply want to upgrade our car audio systems so they sound good when we drive them every day, what are the minimum requirements to ensure that the speakers will sound their best?
For the purposes of this article, let's assume that everything in the audio system connected before the speakers will provide a clean, undistorted signal to the speaker, with sufficient power to reach the desired listening levels for the system. Also for our purposes, we're not going to excessively burden ourselves with optimizing the system for staging, imaging and other qualities that would require many, many hours to achieve. We're going to look only at the installation of the speakers themselves in a simple OEM speaker upgrade system design, and what it takes to achieve excellent frequency response, acceptable volume levels, minimal distortion, and eliminate annoying resonance and rattle issues, with minimal effort.