Car Amplifier Basics
Lets begin by recognizing the different kinds of amplifiers. You have your basic mono channel amplifier, your two channel amplifier, and you have multiple channel amplifiers. A “channel” is only one group of good and bad terminals (+/-) appearing out of the amplifier that you employ to supply power, or drive, to your speakers or subwoofers. A mono channel amplifier has a bouquet of terminals, two channel amplifiers have two, and multiple channel amplifiers range from between 3-5 channels. Now lets get into details discussing their best intended applications. We’ll also answer the questions that are asked most often.
Mono Channel Amplifers- Mono channel amplifiers are usually class “D” amplifiers. Class “D” amplifiers have a superior capacity to heat ratio, which is exactly what you are looking for when powering subwoofers that have to have a large amount of power. Class “D” amplifiers will also be known to be very efficient. Since mono channel amplifiers work best at 2 ohms of impedance, they are ideal they are driving either a singe 4 ohm “dual voice coil” subwoofer, or two 4 ohm subwoofers that only have “one voice coil” each.
How come mono channel amps ideal for these setups? Because every speakers presents a lot impedance to the power that comes to it in the amplifier. This load impedance is measured inside a unit referred to as “ohms”. Most subwoofer speakers present 4 ohms of resistance. If wired correctly, you’ll lower the burden impedance that the amplifier sees. You’ll lower the impedance down to 2 ohms, which is where most mono channel amplifiers are build to perform the very best.
Two Channel Amplifiers- A two channel amplifier is definitely an amplifier that can operate one right, and something left hand channel. It is basically two mono channel amplifiers in a single box. Since two channel amplifiers are typically stable when presented with 4 ohms of impedance, they’re best suited they are driving each one 4 ohm “single voice coil” subwoofer, or two 4 ohm “dual voice coil” subwoofers. To run these setups, you need to “bridge” the channels coming from the amplifier. Not all two channel amplifiers are bridgeable, so be sure that your two channel amp is bridgeable before you buy it.
What’s “bridging”? Lets say that you’re thinking about purchasing a 2 channel amplifier that is rated at 500 watts RMS. You must know the amplifier doesn’t supply 500 watts of power from each channel. Instead, each channel alone will give around 200-250 watts. To get the advertised 500 watts, you have to combine the two channels into one channel. This is called “bridging” the channels.
*Note- Be careful when “bridging” the connections because if it not done properly, then you will destroy your amplifier.
Multiple Channel Amplifiers- Multiple channel amplifiers allow you to connect multiple speakers (typically front two and rear two) while still letting you control your balance and fading options. When shopping for multiple channel amplifiers, you will notice that although the majority are still rated in the 2-4 ohm impedance range, some are rated around 20-40 ohms of impedance. The only real time you’d ever need a guitar amp at this high of an impedance rating is that if you had been to wire multiple speakers inside a “series”. Multiple channel amplifiers may be used to run subwoofers, but you need to make certain the amplifier’s channels are bridgeable since most of the time, each channel of the multiple channel amplifier does not hand out nearly enough watts.
What is “series” wiring? Rather than wiring each speaker separately to every channel of an amplifier, it is sometimes recommended that you simply wire two or more speakers together. When the speakers are wired together, you want to wire the entire unit of speakers to 1 channel from the amplifier. To wire the speakers together, you simply run a speaker wire from the positive terminal of 1 speaker to the negative terminal of another speaker. Once this is accomplished, you take speaker wires from the channels of the amp to your remaining good and bad terminals on your speakers.