Speaker installation is very critical for performance. Whether you spent $1000 or $10,000 on a set of speakers, if they are not properly installed, they would not sound as they should. Even though it may seem that the best position for most speakers are in the stock housing’s that came with the car e.g. on the door panel near your feet, this is just not so. You would see why such positions are still used however along with alternative solutions such as center channels for 5.1 dolby, LCD screen, in-dash DVD players. There are many factors that need to be considered in placing the speakers in the correct position.
The first thing to consider is distance. If the left speaker is only a couple feet away from your ears, while the right speaker is several feet away from you, then the sound will arrive at different times giving you poor sound. Since the left speaker is closer, it sounds louder. The best solution is to figure out a location where the difference between the distance of the right speaker to your ears and left speaker (also known as path length difference), are minimal. This is where kick panels become the preferred location.
Multiple Speaker Placement
If you have a system with two or more speakers per side, you need to try out different locations to obtain the best possible sound in your car. If you have a 2-way system with a tweeter and sub per side. The subs are mounted in the stock location at the bottom of the door. The tweeters are mounted high up on the front corner of the door panel. From the driver’s seat, you can see that there are 4 speakers all aimed towards different orientations and all at a different distance to your ears. This interaction of sound waves at different frequencies arriving at your ears at different times seldom sounds good. The best thing to do is to position the woofer and tweeter on each side as close as possible to each other. This is also why kick panels are used so much these days. Professional installers do use some tricks such as inverting the tweeters’ polarity when mounted for example on top of the dash while the woofers are low. Achieving good sound with unconventional mounting schemes is very, very hard and is only achieved after plenty of time has been spent trying different configurations.
Our ears can distinguish the direction of sound more easily at higher frequencies. This means that aiming the mids, and most importantly, tweeters towards your ears play a critical role in sound imaging. Midbases are not so critical, but should be also aimed towards the listener’s ears if possible. To figure out the best aiming angle involves many hours -even days- of work. To start, try to aim the speakers towards the center of the car. Play around with different angles until you obtain the best sounding position. Subwoofers should be mounted up front for best sound. Since this is not possible in most cars, mounting subs in the back is not such a bad thing, since most people can’t distinguish where bass comes from. If you have good midbases going down to 60 Hz or less and subs picking up the signal below 60 Hz, then the bass will seem to come from the front.
Subwoofers need a properly designed enclosure to give top performance. Midbases and mids also do sound much better if they are installed in enclosures. The best sounding and easier to build enclosure type for midbases and mids is sealed.
If you are using speakers that fit into the stock location, make sure there are no spaces or holes. Sometimes building a wood or fiberglass baffle helps reduce holes and gives you much better sound. Always be careful when using power tools around speakers. Holes in speakers usually are not covered by the warranty. For unconventional speaker locations, sometimes metal has to be cut. If you have the resources, plasma cutters and pneumatics tools work great. For most of us that do not have these tools, a pair of metal snips (left and right cut) will do the job.
Take your time to plan your system and dont just buy brand and product for the sake of popularity. Sometimes the simplest system is the most effective.