Audio Upgrade Guide, Part 5: Less is More

PART 5: Less is More
a.k.a. How an External Amplifier Can Improve Sound Quality

Let’s say you took the leap and upgraded your head unit from OEM to aftermarket. You even swapped out the stock OEM speakers for some nice aftermarket speakers. Let’s even say that you added a decently powered subwoofer, so after all your hard work the result was that you had yourself an all-new audio system, and in your opinion,  it sounds great! If your ears and your wallet are completely satisfied with the sound, you know what? You don’t have to read this section at all. You’re done with your audio upgrade. Go enjoy your nice, new audio system – that’s why you upgraded in the first place, right?

I Want More, Maybe
But… what if you’re not completely 100% happy yet? What if the already improved sound quality (comparing OEM to aftermarket) has a possibility of improving more? Or what if you want to play it louder than it can go? Or say you installed some nice aftermarket speakers, but you are wondering if your head unit’s built-in power is enough? Your gut instinct might be leading you to add an aftermarket amplifier into your system.

A basic aftermarket amplifier sits in between your head unit and your speakers, taking whatever sound your head unit is sending out, increasing the output, then sending that output to your speakers so you can hear louder, clearer sound. Midrange amplifiers will cost a little more but will also have more power, and most likely will have some sort of built-in crossover function and/or equalizers to help you fine-tune your music. High-end amplifiers will bump up the power to extreme levels, plus add in advanced features such as Digital Signal Processing (DSP) and fancy tech, at (of course) a much higher cost. But regardless of the power output, features, or price, all aftermarket amplifiers fundamentally do one simple job: they amplify the signal.

Yes – your stock OEM head unit had a built-in amplifier. Your aftermarket head unit also has a built-in amplifier. So why bother adding a separate external amplifier on top of that? The answer is three-fold: to eliminate any possible distortion, to add more headroom, and to provide more power – all of which contribute to louder, clearer, higher quality sound.

Itchy and Scratchy
Let’s start with distortion. “Distortion” is when the audio isn’t clean – it can sound muffled, or crackly, or raspy. If you’ve ever turned up the volume on any basic stereo system to the point where the sound stopped getting louder and it started sounding really, really bad – that’s distortion. Without getting super technical, just know that there can be many factors that can cause distortion in a car audio system – but the most common two are between:

  • Inferior/Incorrect Speakers: Adding an amplifier that puts out power more than a speaker is rated to handle (such as adding an aftermarket amp to OEM speakers) OR trying to make a speaker play sounds it wasn’t meant to play – like trying to make a midrange play bass frequencies; or
  • Weak Amplification: Trying to use a low power amplifier with speakers rated to use more power than the amplifier can provide.

Since our discussion here began with assuming you already upgraded your OEM speakers to some nice, higher power-capable aftermarket units, we’ll focus on amplification – because it’s a very important portion of creating crisp, clear, clean sound at all volume levels. There is some confusion over the statement that “underpowering your speakers is bad” because most people assume that it means you’ll damage your aftermarket speakers if you don’t give them enough power. But the “damage” part is actually on the amplifier side, not the speaker side. Let’s say you have a 25-watt amplifier connected to a 125-watt rated speaker, the 25-watts is well below what the speaker is designed to handle, right? So there’s no way you’ll hurt your speakers, right? This is correct – but what about the amplifier? The moment the speaker needs more than 25-watts of power to play certain sounds, the amp will struggle because it can’t do it. So instead of that loud clean sound, you’ll get a distorted sound.

As an analogy, let’s say you’re the only person in the front row at a stage, and a band is on stage playing music. They can play at a certain volume level on their own (the blue “cloud” shown below) – with just standard musical instruments and a singer with no microphone – and to you, it will sound clean, clear, crisp, and audible.

Now, what if there were thousands of spectators, all in a packed stadium. That same band will now have to play their instruments at a much louder volume and the singer will have to sing at a much higher volume, to the point that they are no longer capable of being loud enough on their own to project their music and vocals all the way to every audience member. The singer will be screaming, and sound horrible. The instruments will sound forced and on the brink of breaking because the band members are trying to play them hard enough to make a sound loud enough to reach everywhere. The song as a whole is no longer good, it’s distorted because they don’t have proper amplification (a microphone and amplified speakers).

So to sum up distortion: when you try to make a car audio component do more than it’s capable of doing on its own, your music will end up sounding really bad and make you wonder why your nice new aftermarket speakers sound like crap.

I Work Out
Now let’s talk about “headroom”. Headroom is basically when you have more amplification power than you normally need. For example, Let’s say you have a 50-watt speaker that needs amplification. You can power it with a 50-watt amplifier and it will work. You can also power it with a 150-watt amplifier, and it will also work. So why bother with going higher than 50-watts if the speaker itself is only rated for 50-watts? Isn’t that just wasting money? Not exactly. If anything, it’s making sure that your audio system can play sound comfortably, without trying too hard, without using excess voltage, and without affecting the quality of the audio. Take a look at the diagram below: we have two different amplifiers, one is a 50-watt amplifier and one is a 150-watt amplifier, and both are powering the same speaker rated at 50-watts:

Do you see the difference? The smaller R2-200×2 might be capable of providing the 50-watts the speaker can handle, but the amp will have to work at 100% just to do it. That means it will always be at maximum output, and if the speaker wants to play a tone (like say, a hard-hitting bass drum) that requires bursts over 50-watts, guess what? The R2-200×2 will have a hard time providing it. It’s like a person at the gym who can only lift 50 pounds – give them a 50-pound weight and that’s all they can do, and they will have to use 100% effort each time.

On the other hand, look at the larger R2-300×4. It is only working at about 33% to provide the 50-watts of power to the 50-watt speaker. If the speaker gets a bass tone that needs say, 75-watts the R2-300×4 has enough “headroom” to provide that quick burst of 75-watts without breaking a sweat. It’s like a person at the gym who can lift 150 pounds – give them a 50-pound weight and they only have to use 33% effort to lift it – and they can easily lift more weight if needed.

So in the above example of headroom – ideally you’d want to go with the larger amplifier. The larger amplifier is actually working less (thus the title of this article), yet can give you more when you need it. The larger amp can play your music with less chance of distortion, and at higher levels much easier than the smaller amplifier that just barely meets the speaker’s power demands.

Really Loud Noises
Another detail to consider is this: you’re in a vehicle that moves when you drive it. Sure, your audio can sound pretty sweet when you’re testing it out in the driveway right after you installed your gear – but when you get into the real world, things change. Driving along on the streets will introduce road noise, engine noise, and wind noise. All of this noise gets amplified (pun intended) the faster you go, like on a freeway or a highway.

When you go with an amplifier that has more power than your speakers require, you have that extra power to dial up the volume even more to counteract all that added external noise, so you can still listen to nice music as you travel. This is why adding an aftermarket amplifier to your system is a good idea to consider – and to sum up this topic in one sentence: It’s better to overpower rather than underpower your aftermarket speakers.


In Part 6 of this series, I’ll explain why you might want to add weight to your truck to get better sound. What? HINT: Think layers, like a cake.

Guide Posts Listed Below
Intro: Your OEM Stereo Sucks.
Part 1: It All Starts With the Source.
Part 2: Speak(er) the Right Way.
Part 3: You Don’t Drive From the Back Seat.
Part 4: Dogs Underwater
This Post: Less is More
Part 6:
TBA
etc. TBD