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The Weakest Link: Speakers
Choosing the right speakers
When choosing speakers, there are a lot of options. You can get direct-fit replacements for factory speakers, or you can go completely custom. Aftermarket speakers typically come in two different form factors: coaxial/triaxial, which means that there is a tweeter and midrange mounted in the same chassis, or component speakers, such as those pictured here (also called separates). Coaxials have the advantage of producing sound from the same point of origin, which helps stereo imaging. Properly configured components also do this well, and usually sound a bit better.
All non sub-bass sound in my vehicle is provided by a pair of Polk EX-2550 separates. They act like a speaker should: transparent, with no coloring the sound. These speakers are no longer in production, but they are very nice. They tend to sound a little bright with higher volume levels, likely due to their higher sensitivity (more on that in a moment). Purchase and install the largest speaker size you can fit into the front in order to bring the soundstage that much closer to realism. Larger mid-bass woofers will really make a difference. 5 1/4" inch speakers are the norm, but if you can fit a 6 1/2" set in. it will greatly improve the listening experience.
Staging and Stereo Imaging
Door mounted speakers are common, as are kick-panel mounted ones. To get the best sound, try to mount your front speakers as far away from your listening position as possible. This serves to even out the sound so that one side does not seem louder than the other. It is rarely a good idea to have speakers mounted in the dashboard because the windshield glass reflects the treble and can make the sound too bright.
To mount my front speakers in a non-standard location, I used Q-forms kick panel replacements. These things are great - color matched to the car, perfectly angled for good sound.....and dammit they are expensive too but I'll get over it. The factory speakers are still in the doors taking a well deserved rest. The rear speakers aren't even connected. Why? Well, I don't ride in the backseat, and my kids don't care. The premise behind this is that when you attend an audio performance such as a concert, the primary wave of sound comes from in front of you. Factory car stereos typically drive a lot from the rear, which is unnatural. Ironically if your ear is used to factory radio, accurate sound staging might sound a little odd at first. By driving the soundstage from the front of the vehicle, sound reproduction is more accurate and you can hear a lot of normally obscured details in music you think you know. All of your CDs suddenly sound new again.
How to select speakers
When selecting speakers, there are a lot of measurements. These are no substitute for your ears, so whenever possible listen before you buy. Speakers sounds a lot different in a car than they do on a showroom floor.
Whenever and wherever possible, get the largest speaker size you can comfortably fit in the front of the car. 5.25 inch is fairly standard, but 6.5 inch speakers bring a lot of bass up front where it belongs. Mount the front speakers as far as you can from your ears. There is a sound reason for this, but I do not want to go into psychoacoustics here.
What do all those numbers mean?
Frequency Response |
The range of frequencies the speaker (or speaker set) can reproduce. Human hearing does not extend beyond 20 Hz on the low end or about 18-22 kHz (that's 18,000 - 22,000) on the high end. Human voice is around the 1 kHz mark, bright treble is between 8 kHz and up. A good speaker does not make any one frequency in its range louder than the others. Good front speakers should reproduce from about 100 Hz on up. The lower (and therefore bigger) they can go, the better. |
Impedance |
The amount of resistance or burden that is placed on the amplifiers. In a car, this is normally 4 ohms. Factory systems vary widely, so look carefully - many have a higher impedance and produce less movement per amplifier watt. If you install aftermarket speakers that present a four ohm load to a head unit that expects ten (10) ohms, it will run hotter. You can wire speakers in strange ways to get a lot of movement for little effort. |
Peak Power |
This is a useless number, for most purposes. It indicates the maximum wattage a speaker can take on a transient hit, such as hard bass kicks. Never run your speakers close to this rating, you will burn them up sooner or later! |
RMS Power |
The recommended wattage, or power input, from an external amplifier. Whether you install an amp yourself or not, there has to be one somewhere, usually in the back of your radio. The closer you can match an amplifier to the speaker's RMS rating, the better it will sound. |
Sensitivity |
This describes how loudly the speaker will play for a watt of input. There can be other measurements that are called "sensitivity" also. In essence higher ratings in decibels (dB) means the speaker will play louder than one that is equal except with a lower dB rating. So wouldn't higher always be better? The answer is no, if you plan to run outboard amplifiers. Lower is usually better because it eliminates a lot of noise. Higher is better when the speaker is matched to a lower power input, such as a head unit that generates 25w x 4. |
Watts |
An amplifier produces power that is measured in watts. At a given Impedance or load (say 4 ohms), an amplifier may be rated to provide 50 watts RMS. If the amplifier is presented with a 2 ohm load, or impedance, it will typically produce double its rated 4 ohm output. In this example, that means a stereo could be run at 2 ohms for twice the power output. Make sure that you calculate the load (impedance) that you will present to amplifiers when adding/changing speakers. Compare it to what is currently installed if you do not already know. |
