Speaker Info...
Speaker systems are very important because they are the units that actually reproduce the sound from electrical energy. When I buy speakers, I only want to get high end. Here is what you need to know, and what to look for:
First, let's start with the types of speakers that you'll encounter in the car audio world.
Woofer: A large speaker designed to reproduce the lower frequencies of the audio spectrum. Mid: A medium sized speaker designed to reproduce the middle frequencies of the audio spectrum. Tweeter: A small sized speaker designed to reproduce the highest frequencies of the audio spectrum.
There are other variations of these speakers available as well.
You've certainly heard of "subwoofers" that reproduce the lowest of the audio frequencies. Essentially, these are the same thing as woofers, just bigger and with more power handling. The result? Thunderous bass! Like the gods sent it themselves...
You might also encounter "midbass" drivers. These are similar to woofers, but are usually used to bring more bass to the front soundstage. Often times, they are connected to crossover networks.
Another type of speaker you might encounter is called a "supertweeter", and reproduces the highest frequencies in the audio spectrum.
Now, to shock you...
When you buy a "speaker", you are actually buying a speaker system. AKA, more than one thing working together to produce a result. Let's take a look at the types of speaker systems available...
TYPES OF SPEAKER SYSTEMS:
Basically, there are two types of speaker "systems" that exist.
1. "Coaxial", "three way", "full-range", etc.
These speaker systems are designed to fit into the factory speaker location in your vehicle. They are often referred to as a "speaker", but have more than one speaker, and will also contain a crossover. (coaxialspeak.jpg)
2. "Components", "Seperates"
These speaker systems essentially take everything from the above speaker system, and break it up into parts. (componentspeak.jpg)
WHAT'S THE DIFFERENCE, AND WHY SHOULD I CARE?
To restate the obvious, one speaker system has all of its components in one package, and the other speaker system has all of its components in seperate packages. Both speakers do the exact same thing, and work in the exact same way, BUT COMPONENT SYSTEMS ARE BETTER.
Why?
I'll tell you, hoss!
But before I do, you should know about the PROPERTIES OF HIGH FREQUENCIES. OK, it's boring, so I'll give you the executive summary: High frequencies are extremely narrow in their dispersion. (Whu huh?) In short, high frequencies (if we could see them) disperse like a string. Low frequencies, if we can see them disperse like a fan. So, since high frequencies don't disperse very well, they need to be aimed at the ears, otherwise we won't hear them! This is one of the advantages of component systems; they allow the tweeters to be aimed! Why do we want this? So when a singer hits an "s word", or a cymbal crashes (both of these things happen in the higher frequencies), the sound will SPARKLE, rather than sound dead and flat.
PIX: tweeterdisperse.jpg, wooferdisperse.jpg
Another advantage of components: Their crossovers are usually higher quality units than you'll find in coaxial or full-range speakers systems. This is good because you'll introduce less distortion to your speakers, and be certain that your speakers are only playing the frequencies that they're designed to play. The result? BETTER SOUND.
The last advantage of components is that they are GENERALLY designed for people who are more interested in sound quality. Because of this, components are generally higher in quality. When it comes to coaxials, even the most expensive models will be eclipsed by the quality of components in the same price range.
OK, OK. I know not everyone will consider component speaker systems. The truth is that they are harder to install properly and more expensive. Of course, if sound quality is your thing, you'll go through the extra effort! Even car manufacturers are getting with the program these days, and include component speaker systems in their vehicles. Even my lowly Honda Civic has 'em!
Crossovers:
So, you've probably noticed me using the word "crossover" above. What you may not know is what a crossover is, and what it does. Basically, a crossover takes a full spectrum audio signal, and breaks it up into different frequency "bands", and sends the appropriate frequencies to the appropriate speakers. Here's a picture! (xover.jpg)
If this explanation was too simple for you, you can check out my crossover page for more in depth info. Thanks!
OK, OK, OK. It's time to get down to business, and look at speaker specifications, and how they affect you.
Size:
This is often expressed in inches (but sometimes metric for european brands), and refers to the MOUNTING of the speaker, not the actual speaker. For round speakers, the diameter is given such as 6.5" or 5.25". For oval speakers, the dimensions are given, such as 5x7" or 6x9".
Mounting Depth:
Basically, this tells you how deep the speaker is behind its mounting. Most speakers are about 3-4" inches deep. This is important to know because you want to be sure that there is enough room behind the speaker to mount it properly.
Frequency Response:
This tells you what frequencies the speaker is capbale of reproducing. Most good speakers will go as low as 50hz, and all the way to 20,000hz (and beyond). However, if you're planning to add subwoofers to your system, you don't need your speakers to go much lower than 100hz. Also, it's not essential for your speakers to go higher than 20,000hz since us lowly humans can't hear anything in that frequency range.
Power handling:
This is the amount of power a speaker can handle without getting damaged. This is usually expressed in two ways: RMS and MAX. RMS is what the speaker can handle continuously, and the MAX rating tells what the speaker can handle in short bursts.
Impedence:
This is measured in Ohms, and tells you how much resistance the speaker has. Basically, the only thing useful about this spec is so you know what amp to hook your speakers up to. Most car speakers (with the exception of subwoofers) are 4 ohm speakers, and all auto amplifiers are built to handle a 4 ohm "load". Most amps can also handle 2 ohm loads, but 2 ohm speakers are very rare. I would say this spec is much more important when it comes to subwoofers rather than speaker systems.
Sensitivty:
Measured in db, sensitivty essentially tells you how loud a speaker will be. When powering your speakers off of a low power amplifier, you want a more sensitive speaker. When powering your speakers off of a high power amplifier, the sensitivty rating is much less important. Also, more sensitive speakers tend to distort more easily.
A quick word about power handling, amps and distortion...
SPEAKERS DO NOT GET DESTROYED BY VOLUME, BUT BY DISTORTION! As such, it is your main goal to limit the amount of distortion that your speakers receive. Not only does this make your music sound better, but it also protects your speakers from premature damage.
THE EASIEST WAY TO DO THIS IS BY...
Buying as much power as you can afford, even if it exceeds the "power handling" spec for your speakers.
WHAT?!!! WHY??!!!
Because, because, because turning up the volume too high is what causes your amplifier to "clip". This is the worst distortion that you can send to your speakers. It is caused by trying to get too much volume out of an amp that can't provide it. SOOOO, you get a BIG, BAD amp with plenty of power. Now, when you turn up the volume high, instead of pushing the amp's limits, you're just starting to get the amp going. So, instead of clipping, the amp sends a nice clean signal to your speakers. No distortion, no damage, NO PROBLEM!
Now that I've educated you, it's time to think about what you want from your speakers...
Alan Bayer is an entrepreneur and car audio enthusiast. He currently runs an eBay store at:
http://stores.ebay.com/honest-aebs-autosound/
He also has a car audio info site with great articles like the one above:
http://www.honestaebs-caraudio.com/
He is also working on some sorta project over at:
http://www.headunits.biz/