External bass controls (EBC), or remote bass controls (RBC), are a convenient and a handy accessory that allows you to make on-the-fly level adjustments.
For example, If you listen to a wide range of musical genres, then you may want more bass when listening to bass-heavy music such as Rap or Hip Hop and less bass when listening to Country or Heavy Metal.
An external bass knob will allow you to adjust the bass level on the fly without the hassle of having to pull over and adjust the gain setting on the amplifier. Without it your gain would remain the same unless you manually change it.
Knowing how to wire a bass knob can be a little confusing, but just relax, we are here to help!
Even if you’re a relative greenhorn when it comes to car audio, the bass knob wiring diagram and the detailed steps below will help you accomplish this, no fuss, no muss.
Before You Get Started
It must be noted that there’s a common misconception about bass knob’s being the volume knob for your subs, which is not right at all. Thus, it’s of paramount importance to understand what this little knob is actually doing to your audio signal.
In fact, a remote subwoofer control, remote gain control, remote bass control, or whatever you want to call it is actually a remotely located, external gain control that let’s you tune your music on the fly. When you hook it up to your amp, you are essentially bypassing the gain control inside the amplifier.
For that reason, you should be aware of distortion. I mean, before cranking the knob all the way up, bear in mind that you are tweaking the audio signal that you are sending to your subwoofers, therefore turning up the gain too much can cause clipping and audible distortion.
I mean, think about it, if you adjust the gain knob while listening to your music playing, you will notice an increase and decrease in volume. Does this mean the gain knob is a volume control? Of course not. Let’s repeat that. The gain knob is NOT a volume control knob. Got it? Confusing, right?
What is Gain, And What Does It Do?
The purpose of the gain control is to match the output voltage of the head unit (around 0.5V) to the input circuit of the amplifier (how much it amplifies a signal), so that the signal is not over driven which would produce clipping and distortion.
To fully understand what gain is and what it does, think of it like this: Say you have two radios, each of which has a volume knob that goes to 10. One of them outputs a signal at 2.5V and the other outputs that same signal but at three times that (7.5V).
When these two radios are hooked up to an amp, the latter will amplify both of those voltages by the same percentage. However, if you turn both radios halfway through (volume of 5), will the loudness of the music be the same for both?
Of course not. The radio with 7.5V output will sound much louder in comparison to the radio only putting out 2.5V.
Now, if you crank the volume knob all the way up on both radios, what would happen? The 2.5V radio will sound really loud, but the 7.5V radio will blow your speakers, or at the very least blow the fuse or send the amplifier into protection mode.
This is where the gain comes into play. The gain control on your amplifier determines how far you must turn-up the source unit for the amp to make full power. A properly adjusted gain cuts down background noise, distortion and prevents speaker damage.
In our case here, the 2.5V radio will be loud and the 5V will be louder but not to the point of causing damage. You can set the gain to a point where your equipment gets loud at about 3/4th of your total volume swing (ex: 0-10).
Types of External Bass Controls
There’s a wide variety of external / remote bass controls on the market. Technically speaking, most of them are the same thing though they might look a little different cosmetically.
The biggest difference between these external bass controls is how they connect to the amplifier. Different amps may have different types of connections to install the bass control knob.
Some universal bass controls plug directly into the amplifier, others are installed in line with the RCA cables. They have an input and an output. The input comes from the radio / head unit and the output goes to the amplifier.
How to Install Your External Bass Control
Before wiring the bass knob to your amplifier, it is crucial that you set the internal gains on the amp first. In other words, you need to set your gains for maximum bass levels and use your external bass knob to reduce the amount of bass when desired.
Once you’ve set your gain on the amplifier, you can go ahead and install your external bass control.
Speaking of installation, bass control knob wiring varies depending on the model of amplifier and type of connection available for a control knob.
So, choose a location for the knob that is convenient and out of the way. Common installation locations include unused dash locations, inside the center console near the gear shifter, in an empty switch panel, or below the steering wheel. You can also mount in inside the center cubby, so that it’s out of sight.
Some bass control knobs can be flush mounted with only the knob showing and others are intended to be surface mounted with the whole box visible.
Now here’s how to wire your bass control knob:
First of all, connect the RCA signal inputs (Red and Green) to the head unit. Then, connect the RCA signal outputs (Blue and White) to the amplifier.
Next, you’ll need to connect the remote turn-on-wire. The main function of this wire is to “tell” your amplifier to turn on whenever the head unit is powered up.
So, hook up the remote turn-on-wire from the back of the head unit to the “Orange” wire (remote in) in your bass control, and after that connect the “Blue” wire (remote out) from the bass control knob to your amplifier.
Finally, attach the “Red” wire (Positive) to the battery and attach the “Black” wire to the ground.
Bear in mind that the grounding point should be sanded down to bare metal and scraped clean of any paint or primer.
Bass Knob Wiring Diagram