Both bass amps and subwoofers are designed to increase the prominence of low-end frequencies. This could be either for musical performance and recording or purely for listening to audio.
Can a bass amp be used as a subwoofer?
It is possible to use a bass amp as a subwoofer, however, bass amps aren’t designed to project the same depth of low frequencies as a subwoofer. Bass amplifiers mainly highlight the mid-range frequencies of a bass guitar, while subwoofers tend to focus heavily on the sub-bass frequencies.
With that being said, some particular bass amps do have the ability to project the frequencies that a subwoofer is used for.
These sub-bass frequencies are found below 60Hz and go all the way down to the lowest frequency that is audible to the human ear, around 20 Hz. This is generally lower than the bottom frequency of a bass guitar.
In this guide, I’ll explain how a bass amp can be used as a subwoofer in some scenarios.
Bass Amps vs. Subwoofers – The Differences
On the surface, it may seem logical that a bass amp could be used as a subwoofer.
Both devices are designed to promote low-end frequencies. They also share several components, such as specifically designed bass speakers and power amps.
Therefore, one could be forgiven for assuming that using a bass amp as a subwoofer for your home audio system would create the same results.
Unfortunately, like many audio-related topics, it isn’t that simple!
A home audio or theater system consists of three key devices, which are:
The only device out of these three staples of any home hi-fi system that is technically not required is the subwoofer.
Without the amplifier, receiver, or speakers, the system would be inherently flawed. The subwoofer is an optional addition to the audio setup, but the benefits it provides are undeniable.
If we consider a live band on stage, there are similarities to a home audio setup.
You have the main PA speakers which are responsible for projecting the mix of all the instruments and vocals. The bass amp takes care of the low-end frequencies, beefing up the overall sound.
Similarly, in a home audio setup, the speakers are responsible for projecting the bulk of the audio. The subwoofer acts as the bass amp does onstage, focusing on the low-end frequencies to add depth to the overall listening experience.
It’s easy to see, then, why one would assume that a bass amp is interchangeable with a subwoofer. Both devices are designed to highlight and project bass frequencies, which complement the treble that is projected by the main speakers.
- In the same way that it’s possible to plug a bass guitar into an electric guitar amplifier and still hear some of the frequencies, you’ll still be able to hear bass when you use hi-fi speakers with no subwoofer.
However, the sub-bass frequencies will be eliminated from the mix. Even though these frequencies are not as prominent as the mid and treble frequencies, they add depth to the overall sound, and you can feel their presence.
The bass guitar is not solely a low-frequency instrument. Its frequency range spans from 60 Hz – 1kHz, with some additional overtones and harmonics reaching up to 5 kHz.
As I previously stated, sub-bass frequencies reside below 60 Hz and go down to around 20 Hz. Bass amps are designed to reproduce the whole frequency range of the instrument, with equal focus on the mid and high tones. This is what gives the bass guitar its distinctive sound.
Subwoofers, on the other hand, are designed to reproduce the frequencies that lower than the bass guitar is capable of producing. Consequently, if you use a bass amp as a subwoofer, a significant portion of the sub-bass frequencies will likely be compromised.
Take a look at this Bass Amp – Subwoofer experiment on YouTube.
How To Use A Bass Amp As A Subwoofer
If you’re still considering using a bass amp as a subwoofer despite the likely drawbacks, you’ll need to take some necessary measures. One of the most important things you’ll need is known as a crossover.
When configuring your home audio system, bass management is essential because it impacts the performance of the entire sound system. If the bass is boomy, weak, or muddy, it will directly affect the sound of the mid-range and high-end frequencies.
- A crossover is essentially an established frequency where the subwoofer and the speakers work in harmony to cross a threshold, which is determined by a particular frequency.
This is essential when using a bass amp as a subwoofer, for several reasons.
Firstly, it allows you to divide the unfiltered audio signal at a precise frequency threshold. This means that the speakers, or tweeters, receive only the high-end frequencies, while the bass amp is solely responsible for the low-end frequencies.
The majority of modern speakers and subwoofers have onboard crossovers. These are commonly presented in the form of a rotary knob, which allows you to establish the frequency that splits the subwoofer from the main speakers.
In a conventional home theater setup where a 3-way tower speaker is used, the crossover divides the ideal frequencies to suit the three speaker cones. For example, the crossover would send the low-end frequencies to the subwoofer, the mid-range frequencies to the middle speakers, and the treble frequencies to the tweeter.
So, if you were to use a bass amp as a subwoofer, the crossover would perform a vital function.
As we’ve already established, the frequencies that bass amps and subwoofers are capable of projecting vary. Subwoofers generally handle the lowest frequencies much more effectively than bass amps.
Using the crossover, you can determine where the ideal point is to separate the frequencies that are sent to the bass amp and those that are sent to the speakers. The crossover is likely to be different from the one you established when using a subwoofer if you have done this before.
If you’re simply looking for more low-end power from your theater or audio system, you won’t need to be too particular when establishing the crossover. For the average bass amp, choosing a crossover that sends all frequencies below 200 Hz to the device should work just fine.
Indeed, bass amps vary widely in their capabilities.
A top-of-the-range bass amp may be capable of projecting more of the sub frequencies, than a smaller, less expensive equivalent. Therefore, you might feel that setting the crossover even lower would be beneficial.
Bass Amp Specifics
With such a vast range of bass amplifiers on the market, it’s impossible to make a general prediction of whether they are suitable replacements for a subwoofer. A small-sized bass amp that is designed for practicing at home will not provide much of a benefit if it is used as a subwoofer.
Conversely, if you own a bulky bass amp that is designed to be used in large venues, you’ll find it performs the role of a subwoofer much more effectively. Therefore, you should check the specifications of your bass amp before attempting to use it as a subwoofer.
Two of the main deciding factors are the size of the woofer in your bass amp and the wattage that it requires. Also, whether the bass amp is of the tube variety, or a solid-state model will also impact its ability to be used as a subwoofer.
Check out my article on tube amps. You can read it here.
Generally speaking, the larger the woofer inside the bass amp, the better it will cope with the sub-bass frequencies.
However, this also poses the issue of spacing – a large bulky bass amp may be difficult to integrate into a home audio system, without taking up too much space or becoming an eyesore!
Wattage can also be a little confusing when it comes to bass amps. A tube amplifier will use a lower wattage than a solid-state amplifier, but this doesn’t reflect power or output volume.
- A tube amplifier of 20 watts is likely to be louder than a solid-state bass amp of 100 watts.
Check out my article on Bass Amp wattage here.
The table below shows the wattage and frequency response of a range of popular bass amps, to underline their suitability to being used as a subwoofer:
| Bass Amp | Type | Wattage | Speaker size |
| Ashdown C112-300 | Solid State Combo | 25 watts | 12 inch |
| Fender Rumble LT25 | Solid State Combo | 300 watts | 8 inch |
| Orange Crush Bass 50 | Solid State Combo | 50 watts | 12 inch |
| Markbass Marcus Miller | Solid State Combo | 400 watts | 2 x 10 inch |
Related Questions
Does a subwoofer only play bass frequencies?
Yes, due to the specific design of a subwoofer’s speaker cone, it only plays low-end frequencies. These are generally in the range of 20 Hz – 60 Hz, with almost no mid-range or treble frequencies.
Should a subwoofer be placed on the floor?
Positioning a subwoofer on the floor is not ideal. This is because the low-end frequencies will resonate with the surface, and potentially cause acoustic issues. It’s better to use a subwoofer stand to allow the frequencies to move freely.
Can you make a bass amp sound deeper?
One of the most effective ways the deepen the tone of a bass amp is by using a low-pass filter. This cuts out the high and mid-range frequencies, causing the bass frequencies to be more prominent.