Contents

Introduction

Head Units

Cassette Receivers
CD Receivers
CD Changers

Speakers

Amps/Crossovers

Terms

Links:

Amplifing Your Music

Amplifiers could very well be the one thing that changes your whole system. The more power you have(if your speakers can handle it), the better your system will sound. Crossovers pretty much keep the low level sounds out of your highs and the high level sounds out of your lows. This helps the sound as well as protects your speakers. There are many things to look for when purchasing an amp and crossover, so let's get to it:

RMS Power vs. Peak Power:

The RMS rating tells you how much power(in watts) an amp can produce continuously. The peak power rating is the maximum wattage an amp can delier as a brief burst during a musical peak. The RMS rating means more. Manufacturers measure output power using different input voltages. A measurement at 12.5 volts will yield a lower power output figure than a measurement at 14.4 volts. In reality, the voltage supplied by your car vary within the 12-14 volt range.

Total Harmonic Distortion(THD):

This is the amount of change in harmonic content of the signal as it is amplified. A lower figure indicates less change and a more accurate amp. THD below 0.10% is inaudible(can't tell a change) which is very good.

Bridged Power:

In mono mode, you "bridge"(comnine) the stereo output to power a single speaker. Since the output increases, bridging two channesl into one is perfect for driving a subwoofer. A bridged amp "sees" half the rated impedance of a speaker.

RMS Power at 2 ohms:

This spec tells you how much more power your amp delivers into a 2-ohm stereo load. you can acheive a 2-ohm load by wiring in parallel, by bridging, or by using 2-ohm speakers.

MOSFET:

Metal Oxide Semiconductor Field Effect Transistors have a higher switching speed than bipolar transistors and generate very little heat. Their use in the various power circuits of an amp results in faster response and higher efficiency.

Tri-Way Output vs. 3-channel Output:

Tri-Way mode powers a pair of stereo speakers and a subwoofer simultaneously from two channesl of an amp. It's a cost effective way to drive a subwoofer. You'll need a specific external crossover for Tri-Way operation. In 3-channel mode, you bridge the rear channels of a 4-channel amp to run a subwoofer, while the front channels drive a pair of regular stereo speakers. The three-channel option gives you more control over the sound.

Signal-to-Noise Ratio:

Measured in decibels(dB), this spec compares the strength of the desired signal(music) to the level of background noise. A higher value indicates less background noise.

Preamp Outputs

These allow a non-amplified signal to pass through the amplifier and into another amp in the system. Preamp outputs let you run multiple amplifiers without purchasing a seperate crossover.

Built-in Crossovers

A low-pass crossover cuts grequencies above the crossover point--often used to keep high-frequencies from reaching a subwoofer. A high-pass crossover cuts frequencies below the crossover point--useful for keeping low bass away from small speakers, so they can play louder with out distortion.

Crossover Slope:

Crossover slope, quoted in dB per octave, tells you how abruptly the crossover cuts output beyond the crossover frequency. With slopes of 12 dB per octave and above, you'll hear very little output beyond the crossover point. In most applications, the steeper the slope, the better.

Bass Boost Circuit:

This feature allows you to hear and feel more bass from your amplifier. Some models allow you to vary the amount of boost.