FAQ - Amplifiers

Will an amplifier dramatically improve my car's sound?
Absolutely. The amplifier section of both factory and aftermarket radios creates a fraction of the output that an amplifier does. The misconception though is that an amplifier means the system will be very loud. Additional power means that the system distortion will be less at all listenable volume levels. Less distortion is introduced so the music is clearer and has more dynamic range. An amplifier will also allow you to play the system louder if that is what you're after. An amplifier makes the music come alive!

Many aftermarket radios claim high power ratings like 40 watts by 4. Why would an external amplifier be needed as this sounds like plenty of power?
A radio's signal power comes from an integrated circuit and not a transformer. A radio's rated power output may sound high but is typically at a much higher distortion rate than an amplifier's equivalent power and is rated at peak, not continuous power. A radio's power rating is also different as it is measured at a peak level which can not be maintained for any length of time. An amplifier's transformer section can produce significantly greater power, cleaner sound, and more dynamics than any radio's internal amplifier can.

What are high level versus low level inputs for an amplifier?
An amplifier needs an input signal to amplify. A high level signal is the signal that plays through speaker wires. It is called high level because the signal has already been amplified. A low level signal is what runs through an RCA cable like found in your home stereo. Many amplifiers can accept either or an adaptor can be purchased to adjust the input accordingly.

Aftermarket radios often have RCA signal outputs, which can be plugged directly into an amplifier. If you'd like to hook up an amplifier to a factory radio or radio without RCA outputs, you will need to purchase an amplifier that can accept a high level input or purchase a line level adaptor.

How do I know how much power I need in an amplifier?
There is no exact science to amplifier requirements although subwoofers will require more power than full range speakers. Typically a subwoofer should see at least 50 watts per speaker while full range speakers should see 25 watts per channel or more. Your financial budget, system design, and brand preference will dictate how much power the amps will have. One rule is to be consistent in amplifier power among the speakers so the front speakers aren't way louder or softer than the rest of the system. Subwoofers are power hungry though and can take about all the power you can give them.

Overdriving a lesser wattage amplifier will increase the distortion level, make the amp heat up, damage the speakers, and shorten the life of the amplifier.

Are amplifiers easy to install?
An amplifier requires multiple wiring connections and vehicle disassembly so it should not be attempted if you do not have the time, tools, and knowledge. Power wire must be fed through the firewall, the radio removed, and wires ran from the front of the car to the back. Improper running and protection of the power wire can cause a fire and damage a car severely. An amp's performance also hinges on a proper installation so there is no noise in the system and the gains are set correctly. The enjoyment of the amplifier will be higher if the installation is done be a certified installer.

Can I hook up an amplifier to my factory radio?
Absolutely. An amplifier that accepts high level inputs would be your best choice because the audio output from your factory radio is high level. Signal adaptors are available that can adjust the signal to RCA level if you want to add an amp that does not have high level inputs. Some vehicles with amplified speakers or other complex components may require different speakers or adapters too.

What is needed to hook up an amplifier?
An amplifier needs both signal and power wiring in order to work. The power wiring includes either 4, 8, or 10 gauge wire depending on the number of amps and the amp's current draw. The more powerful the amp, the thicker the power wire needs to be to provide sufficient current for the amp. The gauge is the opposite of what you might think though: 4 gauge wire is thicker than 10 gauge. Fusing at the battery and ring terminals are needed to protect and secure the connections.

The audio signal will require an RCA cable unless connecting speaker wire to the amplifier as a high level input. Speaker wire will also be needed to run the amp's output to the speakers. Amplifier kits are available that include all the necessary wiring and hardware for an amp installation. This approach usually saves you money and includes all required cabling.


What does "bridging" mean when talking about amplifiers?
An amplifier that can be "bridged" means that the output power can be summed to provide twice the power or more into one speaker. For example, a 2 channel x 50 watts amplifier can be bridged to one channel x 125 watts. An amplifier that can be bridged provides more flexibility as it can be used as a 2 channel amp one day and then bridged to a subwoofer the next. Driving subwoofers is often accomplished by bridging an amplifier because of the increased power output.

What does it mean when an amp is stable to 2 ohms?
Amplifiers must be flexible depending on what speakers and how many get hooked up to it. For example, a bridged amplifier may get hooked up to one subwoofer or 2 subwoofers wired in parallel. The "load" or work that an amplifier must do is measured in its stability down to __ ohms. Bridging and amplifier and adding more speakers increases the load and reduces the ohm impedance that the amplifier will see. Some amplifiers are designed to take extensive loads and may play down to 1 ohm or lower while other amps work best seeing a 4 ohm load. If a greater load is put on an amplifier that it was designed for, it can cause the amp to overheat, shut down, and live a shorter life.