Audio Terminology 101

Hey i was looking throught the forums and all i read is crap about "which subs and maps are better" or "should i get...". I am tired of reading this nonsense. Being a noob, all i want to learn terms of audio components. Things such as what does ohms stand for, what do watts detrermineand what do the effects of different channels and ranges and all that crap have on sounds? Why are there different "types" of subs? What type of power is being pushed through amps to subs and how exactly do these woofers work? Now here is where you guys come in. I have done some research for myself, but i was hoping that people like you could make it possible for people like us to understand. Any and every information will help everyone out there so let us know what you do...thanx a million.

ohm - a measure of electrical resistance, just like a foot is a measure of distance. 1 volt applied across 1 ohm will yield 1 amp of current (I=V/R where I is current, V is voltage, and R is resistance)

watt - a measure of power, in the electrical world, 1 volt * 1 amp = 1 watt (P=IV). More power can move the speaker farther, yielding more output

channels - a power amp, in the simplest form, takes in a voltage with basically 0 current, runs it through an electrical circuit to step up the voltage (so a 5V input gives you a 20V output for example), and it uses an external power source to provide current for this output. Basically, if you were to attach a speaker onto the headunit's preouts (that voltage with 0 current), the circuitry in the headunit wouldn't be able to support the current and the voltage would drop down to almost nothing, or it would fry the headunit's preouts. Instead you feed this voltage to an amplifier, which basically mirrors the voltage onto its own outputs, and it uses power from the battery to support the current draw so you can actually run speakers off of it. A 2 channel amp has 2 of these in one chassis, it takes in 2 separate voltages (normally "left" and "right"), it does its thing, and it has 2 outputs for speakers. A 4 channel amp does the same thing but with 4 inputs and 4 outputs

ranges - not sure what you mean

"types" of subs - you'll need to be more specific

the power thing - audio is AC (alternating current), basically if you were to play a pure tone (imagine plucking the string of a guitar and just letting that one string resonate), it would look very similar to a sine wave, it oscillates between positive and negative voltages and currents, just like the electrical outlets in your house

how do speakers work - essentially, a speaker is an electromagnet sitting inside a permanent magnetic field. The leads for this electromagnet are connected to the amplifier, and the electromagnet itself is attached to a cylinder/cone which is free to move on only 1 axis, up and down (assuming the speaker is facing up). When a voltage is applied across the terminals on this electromagnet, a current flows as a result (remember I=V/R above, R is the "ohm" spec that the manufacter tells you). This current running through the coil induces an electromagnetic field. This electromagnetic field fights with the permanent magnetic field and you get an equal and opposite force pushing on each (like 2 permanent magnets, if you hold them close to each other they either push away or attract, depending on the polarity). Since the permanent magnet is connected to the basket and the box and everything very rigidly, it can't move, but the electromagnet is free to move, and that force makes it do so. So this current makes the magnetic fields fight and it moves the cone. Well like I said above, audio is AC, so after a short amount of time, the voltage and current switch polarity (if it was + it's now -, if it was - it's now +). This changes the polarity of the electromagnet, and instead of it pushing the cone in one direction, it pushes it in the other (like flipping those magnets around, if they were pushing away from each other and you flip one of them over, they'll now be attracted to each other). So if it was pushing the cone out, it's now sucking it in. Well if you repeat this process very quickly, you can imagine that the cone will basically be vibrating back and forth. Depending on the frequency of the switching, this vibration will become audible. The normal audible range for humans is 20hz to 20,000hz (aka 20khz). 1 hertz is equal to 1 oscillation per second, so 20hz means that the voltage/current/cone is switching back and forth 20 times per second, and at 20khz it's switching back and forth at 20,000 times per second.

A good site for the basics is www.bcae1.com

ohms is the resistance of a speaker. The higher the ohms a speaker is, the less power it will get from a certain amp. A 2 ohm speaker will get much more power than an 8 ohm speaker will from the same amplifier. Some amplifiers are not capable of running in 2 ohm mode, so you have to be careful. two 8 ohm speakers running on one channel will combine to equal a 4 ohm load, two 4 ohm speakers on the same channel will make a 2 ohm load.... etc... Watts are power. If an amp says it is an 800 watt amp, then it will supply a maximum of 800 watts to your speaker(s). However it will only put out about 400 watts continuously. The term for that is RMS. an "800 watt peak" amp is a "400 watt RMS" amp. (Generally) thats just a rule of thumb, so read the box, or the manuals to find out the exact numbers. And the total number of watts decrease as you use more of the amps channels. There are a million different ways to hook up speakers to equal different ohm loads to suit the amp. Once you learn the basics, you can make your equipment much more effective. different types of subs would be like... "Single Voice Coil", or "Dual Voice Coil" (DVC). They can be all different ohms. If it is a DVC then it will have 2 positive inputs, and 2 negative inputs on the back of the speaker. A SVC sub will only have one of each. IF you have an 8 ohm DVC sub, and you hook up both voice coils to one channel, then it will produce a 4 ohm load. Plus, look at the manuals for your subs to see what is the recommended RMS power for them, and make sure that its not too much, or too little as compared to your amps RMS wattage. If you need much more info than that to get started, then you can go look for a web page or something. Theres enough information about this stuff to write books, but you dont need all that yet until you at least go through a few systems. maybe some people will think of a few other things you might need to know to get started.

i havent read his yet, but I think its better than mine, lol

sr20 got most of them down, rick u might wanna make urs less confuzing heh

also rick the power doesn't "lessen" it just changes according to the ohm load it sees, u can get from any kind of power from any amp, it just some amps will explode lol

also the rms is what you'll want to be matching

the "peak" value will only be reached during certain beats and hits in your music

also when he said range im assuming the frequency range that some speakers will play too, or are cut off at

and.. yes you'll need to be more specific on what you want to know about "types of subs"

the more channels you use, the less total watts you will get from the amp when keeping ohms the same. I wasnt wrong about that. I didnt say about keeping the ohms the same the first time, but I provided enough information to assume that.

the more channels you use, the less total watts you will get from the amp when keeping ohms the same. I wasnt wrong about that. I didnt say about keeping the ohms the same the first time, but I provided enough information to assume that.

not sure what you mean

If you have a 2ch amp and you're only using 1 channel, you won't lose power by attaching something to that 2nd channel. Now if you're talking about having a bridged amp and then unbriding it, sure, but that's completely different.

yea thats how I meant it (bridged to unbridged). I should have been more precise about it. I was just figuring it nonsense to only use one channel rather than bridge.

http://www.bcae1.com/

pretty much everything you want

again i want to thank all of you guys for your time to reply to my post. You have just saved my life. Hopefully now i wont be walking into Sountronics with no balls and no sense of what i am talking about. oh, and by "ranges and types" i think i am talking about something i read about differnt subs for higher and lower frequencies? correct me if i am wrong, i prob. am thanx again