When should you run Speakers off the Head Unit and when should you add a 4-Channel Amplifier?
April 4, 2019 by Coleman Thedinger
It’s not uncommon for us to hear from customers who are looking to make the biggest improvement to their car’s audio system, with the least amount of intrusion or cost.
Speakers are usually the first item on the list, since they’re relatively easy to replace and even some of the most affordable ones will blow stock speakers right out of the water. Everyone gets excited about new speakers, and it’s a good way to unlock that next level beyond stock audio but running those speakers off the same head unit will only take you so far.
Stock speakers are powered by your head unit, using what’s referred to as deck power. When you add better speakers, that usually means you’ll want to look into adding an amplifier as well, because the new speakers are going to be more demanding than your stock ones.
While your car’s stock configuration can handle the low-power, unimpressive stock speakers with ease, once you start adding better components, that changes everything. Remember, there’s a reason you’re replacing those stock speakers in the first place.
Your stock head unit is going to be very low-powered compared to adding an amplifier. You can check the specs and see how demanding your new aftermarket speakers are, but if you really want that clear sound, where frequencies sound distinct, and everything comes together nicely, then an upgrade is in order.
Advantages of Adding a 4-Channel Amplifier
With a dedicated amplifier to power your front and rear speakers, even if they aren’t the most demanding speakers, you’re going to get clearer sound, louder volumes, and less distortion.
There are aftermarket head units that can deliver more power than a stock head unit will, but they still pale in comparison to having a proper amplifier.
Your amplifier will allow you to setup crossovers, so that the correct frequencies are doing to each driver, to give you the best sound that your system can produce.
So, why doesn’t everyone use Aftermarket Amplifiers, then?
Installing an amplifier is a DIY project that you can complete yourself or get done professionally. It’s not hard to do, but it does take some careful planning and there's a lot that can go disastrously wrong if you aren’t careful. The cost, and the fact that it can be kind of intimidating, both factor into why some people will choose to keep running their speakers directly from the head unit, even though the quality and sonic potential is greatly diminished.
If you really want to avoid the cost and effort of getting an amplifier installed, or you can’t give up an inch of trunk space, your options are limited. Finding a head unit that can deliver as much power as possible, and not being a bass head, and not wanting to listen at super high volumes is the use case for sticking with deck power, but it’s still not ideal.
What You’re Missing out on When You Use Deck Power Instead of an Amplifier
As you get deeper and deeper into the rabbit hole of car audio, it’s only a matter of time until you hear about strapping amplifiers. There are many misconceptions about what this does, how it works, and what it’s for. We’re going to go over the benefits of strapping your amps instead of just having one big amp, why people do it, and finally how to strap 2 amplifiers.
The biggest issue with using your deck’s power instead of an amplifier always comes back to sound quality. It takes more power to produce higher quality sound at higher volumes.
In terms of audio quality and performance, here’s a quick rundown:
Worst: Using your stock speakers and stock head unit.
Still Bad: Using aftermarket speakers with your stock head unit.
Middle-Ground:Using aftermarket speakers and an aftermarket head unit.
Better: Using aftermarket speakers, aftermarket head unit, and one amp.
Best: Using aftermarket speakers, aftermarket head unit, a 4-channel amp for your front and rear speakers, and a monoblock amp for your subwoofer.