Can someone give me a high level explanation about what a channel is as its associated to an amplifier? Some have 2, others have 8; I have two floor speakers, one center, and one sub - I would like to add an amplifier to this home system.
Do you want an amplifier or do you want an A/V receiver?
Most people want an A/V receiver. This will take your audio from multiple sources, such as a Blu-ray Disc player, game console, and cable box, and decode digital audio (from HDMI, etc.) and then includes the amplification for the speakers inside of it.
When you hear that a amplifier has 8 channels, it means that it can power up to 8 separate items individually. Kind of like if your cable box has 10 channels, it means you can watch 10 individual shows.
Most A/V surround receivers are 5.1 or 7.1 which means they have power to run 5 or 7 different channels.
Does 1 speaker = 1 channel?
For the point of this introduction we will say yes. In reality, you can power multiple speakers off a single channel, but this would NOT be typical from a typical home theater setup. Likewise, there are times when you want to dedicate two channels to one speaker. Once again, this is not typical and not really worth discussing for a entry level setup.
What matters to you:
You have a left, center, and right speaker which needs amplification.
Your subwoofer (make? model?) should have a built in amplifier as well. If not, it may not be worth using... Or, you may want to get a specifically dedicated subwoofer amplifier for it.
If your subwoofer is amplifier, the most typical solution is to just add a surround A/V receiver to your setup and go from there!
