Car Amplifier Basics

In short, a car amplifier’s job is to boost the power and volume of your car audio system. Generally, the head units you find in various cars already have built-in amplifiers. They’re not great, but good enough for day-to-day music listening on the road.

If you’re interested in adding an amp to your car audio setup, there are some things that you need to consider. What are they? Just read on to find out.

Power Ratings

A good amp can make a world of difference, and a lot of folks rate how good an amp is from its power rating. Let’s take a look at the most common terms we’ll see manufacturers use for their amp: max power and RMS power.

Max power is rubbish. If you see a car amp which boasts maximum power only, that should raise a warning flag in your head. Almost no one run their car audio system at 100% power all the time, and your car’s electrical system most likely can’t handle such a load. For now, it’s safe to say that maximum power is just one big marketing jargon that manufacturer’s use to lure the less informed.

Pioneer GM-A6604 4-Channel Car AmplifierWhat you want to see is the RMS (Root Mean Square) rating. It shows how much power the amp can continuously deliver to your speakers. A 500-Watt RMS amp may have over 1,000-watt of maximum power but the power it can continuously push to your speakers and subs are just 500-Watts. That means if your overall speaker setup need like 750-watt they won’t work well. Not just slightly worse, but really terrible to your ears. The amp just doesn’t have enough oomph to work optimally.

Active VS Passive Crossover

A crossover’s job is to separate low, mid, and high frequencies and deliver them to the proper channels. There’s an active crossover and then there’s a passive one.

A passive crossover splits the frequencies that have been boosted. This implies a power loss because not all the boosted frequencies are “useful”.

Active crossover do things rather differently. It does the splitting before the amplification. This is good because the amplified signals are the ones that matter — the ones that your speakers can handle properly.

2-Channel, 4-Channel, Or 5-Channel?

The number of channels shows how many speakers you can connect the amplifier to. People usually use 2-channel amps to power two 6×9 or 6.5 speakers located on the front doors. When they want to power two on front and two on the back, they use 4-channel amps. A 5-channel amp is used when you want to power four speakers plus one subwoofer.

So, Which Car Amp Should I Buy?

A lot of people are asking the question. But let’s rephrase it a bit to, “What car amplifier do I need?”.

Yes, the kind of amplifier you should get depends on your car audio setup and what you need to improve it. For instance, if you just want to simply upgrade the two stock speakers on the front then a 2-channel amp will suffice.

What’s that? You want to add a subwoofer on the back because you feel the bass is lacking? Then get a 3-channel amp. Two channel for the front speakers and one of the sub. Or get a 4-channel car amp and bridge the two channels to power the sub.

Why should I bridge my amp?

So you can put more power to your sub, my dear. When you bridge the two channels you are effectively quadrupling the power sent to the subwoofer. That way you can install more powerful subs to give you the bass punch you always wanted.

Note that not all amplifiers are stable when bridged. Some are just better than others. Do consult the manual before you try bridging the amp.

How many watts do I need?

It depends on the speakers you install and how much power do they draw. If your whole speaker setup requires 400 watts make sure you get a 400 Watt car amplifier. Note that you want 400 Watt RMS and not peak power.

What brand should I buy?

Any brand you like. If you’re still unsure then stick to the known names like Rockford Fosgate, Pioneer, Clarion, or Alpine.

Rockford Fosgate PBR300X4 Punch BRT 300-Watt Ultra Compact 4-Channel Amplifier

How much will it cost me?

Relax, a good amp won’t necessarily cost you an arm and a leg. For example, the Rockford Fosgate PBR300X4 300-Watt 4-Channel amplifier shown above is only about $160. That one is really compact too, so it’s perfect for small cars. You can even install it on your motorcycle. It’s really a good deal.

Still got an unanswered question? Feel free to ask us using the comment box below.

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