The United States, the world's biggest oil consuming country, consumed 18.5 million barrels of oil per day (mbd) in 2012, which accounted for nearly 20% of the world's total oil consumption per day. The highest level of oil consumption in US history was 20.8mbd, which occurred in 2005.
It is also important to be conscious of the speakerâs sensitivity rating, measured in decibels (dB). The higher the number, the less power a speaker requires in order to reach higher volumes without distortion. For most car speakers, this number typically ranges between 88 to 92 dB.
Think of a channel as being an amp. A mono channel obviously is one amp. A two channel is two amps and so forth. A four channel amp is typically used for the four speakers in the car (two front, two back). A mono or two channel amp is usually used for subs. The number of channels on an amp doesn't limit it to the number of speakers you have connected, but impedance (ohms) and the frequency being sent to specific speakers does.