Connecting two subwoofers to a one channel amp can take the bass to new heights and improve the sound but it comes at a cost – the wiring must be perfect. Here’s a guide that details all the steps on how to connect two subwoofers to a one channel amp, plus ways you can wire both devices.
All You Need to Know Before Connecting Two Subs with a One Channel Amp
Because a one channel amplifier is designed to work with one or no subwoofer, connecting two subs with a single amp requires a bit of technical know-how. Here are a few details you should have in mind before joining the two devices together in hopes of a good, smooth bass:
Voice Coils
If you have two subwoofers on hand or plan to get one, make sure to choose the right voice coils for your system. A single voice coil subwoofer doesn’t necessarily perform better or worse than a dual voice coil subwoofer, but the latter is easy to configure because it offers multiple wiring options.
Wiring
The key to a good ‘two subs with one amp’ stereo system is the wiring. There are generally two methods of wiring available for amp and subwoofer connection, i.e series and parallel. The better the wiring of the voice coils and subs, the better the impedance load on the amplifier.
Impedance
The speaker impedance and load is the next essential feature to consider when connecting multiple subs to a single channel amp. It refers to how much load a speaker puts on the amplifier. Impedance is adjusted according to the amplifier’s power capabilities.
Maximum Load
When you’ve figured out the type of voice coil that’ll work for your system, wired the subs, and tested for the power output of your amplifier, it’ll help you understand what is the optimal load for your system. Knowing the range of minimum and maximum load can save you from the amp accidentally short-circuiting.
What Should You Know About Speaker Impedance?
Speaker impedance is, in simple terms, a ‘restrictive force’ on the current that balances the load on the amplifier and works to create harmony in sound. It does not have a constant value, instead, it varies with different frequencies and power.
Speaker impedance is measured and denoted by ohms and it’s important to understand its significance when connecting speakers, amplifiers, and receivers as one wrong connection can lead to clipped or distorted audio.
To perfect speaker impedance, you will need speaker wires that match the speaker output on the receiver. They are made in many different materials and sizes so users can choose one that best fits their system.
You can find two types of speaker wires:
- Aluminum core with copper coils
- Dual-strand wire core covered with a larger wire coil
The dual-strand type is the most popular choice when connecting multiple subs to an amp.
Why is Speaker Impedance Necessary to Run an Amplifier?
Speaker impedance helps run the amplifier at its optimal power so that the input signals are processed smoothly and the output sound is undistorted and clean-toned.
Since it’s a ‘restrictive force’, the lower it’s set to, the greater the current flow will be which will increase the load on the amplifier and result in a powerful sound.
On the other hand, the higher the impedance is adjusted, the lower the current will be which will decrease the load on the amplifier and result in an average voice.
When adjusting the impedance load to its maximum, make sure the amplifier is capable of running at such a powerful speed.
Ways to Wire Two Subwoofers to a One Channel Amp
The key to ensuring the connection of multiple subs to a one channel amp will work is how well you wire them together. The better the wiring, the better the performance will be. There are two ways that you can use when connecting two subs with a one channel amp:
Series
In this method, subwoofers and an amplifier are connected like a ‘series’ which leads to a cyclic loop of connection.
The positive terminal of one subwoofer connects to the positive terminal of an amplifier. The negative terminal of the subwoofer connects to the positive terminal of the second subwoofer.
This leaves behind the negative terminal of the second subwoofer which is connected to the negative terminal of the amplifier, forming a cyclic loop of connection.
The series method of wiring is the simplest.
Parallel
Evident by the name, in this method, a subwoofer and an amplifier are connected in parallel which leads to a dual-loop connection.
The positive terminal of one subwoofer is connected to the positive terminal of the amplifier with one wire. The subs negative terminal is connected to the positive terminal of the second subwoofer.
The negative terminal of the second subwoofer is then joined with the negative terminal of the amplifier with another wire.
The parallel method of wiring allows a multiple subs connection but decreases the overall impedance load of the circuit.
As the subs and amp are connected parallel to each other, the impedance can be calculated by dividing the impedance of one sub voice coil by the total number of subs you’re connecting.
How to Connect Two Subwoofers to a One Channel Amp?
Now that you have a clearer idea of what to look into and how to wire the subs and amps, here’s a step-by-step guide on how to connect two subwoofers to a one channel amp:
- First, determine what wiring method you’ll choose.
- If it’s a parallel connection, join the positive terminal of the first sub with the positive terminal of the amplifier with one wire, and the negative terminal of the second sub with the negative terminal of the amplifier with another wire.
- For a series connection, you’ll join the positive terminal of the first sub with the positive terminal of the amplifier, and the negative terminal of the second sub with the negative terminal of the amplifier using just one wire.
- After the wiring, the two subs must be connected with the one channel amp.
- Now calculate the impedance so you can adjust how much load is being placed on the amplifier.
- In a parallel connection, divide the impedance of one sub voice coil by the number of subs, which in this case is 2. For example: if you have connected 8 ohms subs in a parallel method, the overall impedance load will be 4 ohms as 8/2 = 4.
- In a series connection, simply add the impedances of each sub or voice coil connected and you’ll have the total impedance load.
Please note that in a series method of wiring, the whole circuit could fail even if one sub malfunctions as all terminals are connected with each other.
In a parallel method of wiring, you have a good chance of saving the circuit if one sub fails to deliver sound.
Frequently Asked Questions:
Can you run two subs with the same amp?
Yes, it is possible to run two subs with the same amp. To work well, each subwoofer would have to be powered by a compatible amplifier along with a reliable power source. The wiring needs to be perfect as well or else one woofer could be running with better sound than the other, disrupting harmony.
Can you wire two speakers to a one channel amp?
Yes, you can wire two speakers to a one channel amp. Make sure to wire them correctly – either in series or parallel. Before selecting the wiring method, note the load impedance on each speaker as that is what will take the guesswork out of the wiring methods and decide the best way for you.
Are two subs louder than one?
Adding another sub to your stereo set can enhance the volume of your music such that you’ll be able to notice the soft and high tones. However, it is generally made to amplify the bass of your music and balance the notes so your music may feel smoother than louder.
What channel amp do you need for two subs?
It depends on the load impedance. The power of the subs must match the amplifier’s power. This compatibility will result in the harmony of bass when you play music on the stereo. For example, you’d need two 250 watts RMS subs to connect with a 500 watts RMS amp.
Final Thoughts
Adding another subwoofer to your stereo collection can be a daunting task especially if all you have is a one channel amp and no room for more. But now that you know how to connect two subwoofers to a one channel amp, the process will go by like child’s play!