Although every subwoofer is slightly different with its setup, it is often possible to set one up when you don’t have a sub out.
We see subs getting used with multichannel processors, preamps, and home theater systems.
In these situations, they almost always have a specific channel called the “subwoofer out.”
It’s sometimes referred to as the low-frequency effects (LFE) or .1 output.
If you have a stereo system, should you simply connect the sub to your network without the output present?
Using a Subwoofer without a Subwoofer Output
If you want to connect an active subwoofer to a receiver without a sub out, you can either route it through the preamp or have it serving as a standard speaker in your setup. The only way these options won’t work is if your subwoofer doesn’t have speaker-level connections.
When you have a passive subwoofer to add to your setup, you must have an external amplifier available that delivers power to the unit.
Receivers don’t have the capacity to provide signals or provide power so that your sub works as intended.
If you have a passive subwoofer, you might connect the receiver to the amplifier to get it working.
You’d route the sub to the amp to get the lower frequency sounds that you want with your audio after that step.
That’s why the best option is to use a powered subwoofer whenever possible.
The active setup ensures you have more flexibility, especially when there isn’t a sub out option to use when creating your system.
How to Connect a Subwoofer to Your Setup Correctly
With most subwoofers sold today, you’ll receive an instruction booklet that outlines the exact procedures to follow when connecting the equipment.
Since every system is a little different, you’ll want to refer to this owner’s manual whenever possible.
If you connect your subwoofer in ways that the manufacturer didn’t intend, you could be voiding the warranty.
That process includes skipping a connection to a sub out line.
You must also be careful when setting up your sub so that it doesn’t overwhelm the listening experience.
If you have the EQ set too far toward the bass, it’ll be like adding an entire bottle of siracha sauce to your enchiladas instead of the prescribed amount.
You can still enjoy it, but you’ll taste mostly siracha.
When you connect your sub, it’s essential to remember that room acoustics play a crucial role in the final listening experience.
The sound waves bounce and reflect more often because of their shape, which means the speaker performance can be impacted immediately.
Since many subs come with an A/C power requirement, you’ll need to consider managing the lack of a subwoofer out in practical terms.
The best way to manage this system is to follow the 5-C Rule: connect, control, crawl, check, and combine.
This process, established by The New York Times’ Brent Butterworth, allows virtually any subwoofer to connect to your system without consideration for the other audio gear used for the rest of the setup.
An Overview of the 5-C Rule for Subwoofer Connections
When you have your subwoofer ready to connect to the rest of your system, here are the five steps to follow when implementing the 5-C Rule for your setup.
■ Step #1: Connect
When you use a subwoofer with a home theater system, the connection is straightforward.
All you need to do is run an interconnect cable from the receiver’s sub output to the line input.
If your subwoofer has an LFE input, you should use that one.
Most systems lack the sub out with the setup, which means you can connect your subwoofer using an extra set of speaker cables.
That’s assuming your system has speaker-level connections that you can use for the links.
You’ll want to run the left and right cables from the receiver to the sun. You can then wire from the sub to the speakers to get the sound you want using the same connection sequence.
When you need to connect your subwoofer to a computer audio setup, you might need to use the line outputs that are part of the system.
If that option isn’t available, you’ll need a Y-adapter to complete the work.
You’ll connect one leg to the computer speakers and the other to your sub’s line input to generate the sound.
If you get a hum after finishing the setup, that means you’ve plugged the subwoofer into a different A/C outlet than the rest of the system. You get a 60 Hz hum after creating a ground loop.
You can get this feedback from damaged cables or improper connections.
When those look secure, you’ll want to get a power strip large enough to manage your entire setup from a single station.
■ Step #2: Controls
If you’re using an inexpensive subwoofer for your listening needs, you’ll find two primary controls available to use. They are the crossover frequency and the unit’s volume.
When you see the crossover frequency rating on a subwoofer, that information lets you know what the highest tones are that the speaker plays.
If you set this rating too high during the manufacturing process, a soprano could sound like a baritone because of how the voice gets transmitted through the sub.
If you set the crossover frequency too low, you’ll find the baritone voice sounding closer to the soprano instead.
That’s why you’ll want a subwoofer that picks up the sounds where the rest of your speakers stop transmitting.
It helps to review your system’s spec sheet to see what the lowest frequencies are for all sounds.
Most mid-range speakers have a frequency response range of 60 Hz to 20 kHz. That means you’d want to set the crossover frequency to 60 Hz on the subwoofer to avoid unusual sounds coming from the system.
It is okay to have your sub running a little higher than your speakers’ lowest range.
The low end is often a struggle for the standard setup, which means the subwoofer can occupy more room in that area without overwhelming the audio mix.
■ Don’t Believe Everything You Read on Speaker Specs
Speaker manufacturers tend to be a little optimistic when discussing the frequency range for their products.
If you see a spec sheet that rates the unit as having a response that hits 40 Hz, you might hear a “hole” in your sound if you set the sub to the same setting.
When completing your setup, you’ll want to start with the crossover frequency to see how accurate the manufacturer’s description of the speakers is.
If the audio sounds thin, whispy, or hollow, that means you’ll need to set it higher on the sub to fill in the holes.
If you’re setting up a subwoofer with a home entertainment system, you should use the reverse in your setup. Set the subs to the highest point they’ll reach and let the speaker crossover setting match that instead.
The standard crossover frequency for most home speakers is 80 Hz. If you have small subwoofers (four inches or less), you could go as high as 120 Hz to take some of the pressure off of the rest of the setup.
■ Set the Volume Relative to the Other Speakers
When you set the subwoofer volume of your speakers, you’ll want to use the testing tones to create the right EQ levels for listening. You’ll want to keep the controls at 50% of their capabilities to achieve the correct levels.
If you don’t get the results you want at 50%, try setting the tones at 75% the second time. That’s when you can fine-tune the levels to create the audio balance you prefer.
Some users get worried about having= the subwoofer volume rise above 50%. The internal limiter will prevent distortion while protecting the amp and driver.
Unless the sound quality decreases immensely, you should have nothing to worry about with this step.
When you use a more personalized subwoofer system, set the volume so that the sounds are what you prefer where you usually listen.
It shouldn’t be thin, but the audio should also provide consistent outputs without booming your hearing out of existence.
If you have a phase control on your subwoofer, you can adjust the timing so that the sub matches the rest of the system.
Some speakers have room-correction technology built into the unit.
You can try it out to see if the modified sounds provide a balanced audio experience, but it is not unusual to have things become worse.
■ Step #3. Crawl
Two factors play a significant role in how you experience sound: where you listen to it and your subwoofer placement.
If you put a subwoofer into a corner, it’ll provide more of a booming arc to the sounds it produces.
When you have it in open space, you’ll see some frequencies get boosted while others get nerfed.
The effects will differ based on where you choose to sit when listening.
Smooth surfaces reflect sound waves, which means the bass frequencies will ricochet in different ways to create new audio opportunities.
Your ears don’t detect where the most resonant bass sounds originate, which means you have more flexibility with subwoofer placement.
As long as you can complete the connection, the response will be positive.
If you’re unsure where to place a subwoofer in your room, here are the steps to follow to find the optimal spot.
- Place the subwoofer in the chair, sofa, or another seat that you use the most when listening to music, watching TV, or enjoying other audio.
- Play a song with a melodic bassline to it.
- Crawl around your room, on your hands and knees, placing your head near the floor.
- Look for the place where the bass line sounds the most balanced.
Once you find the best EQ using that technique, you’ll have the perfect listening arrangement for that one seat.
That’s the problem with the crawl methodology. Every other seat in the room might need a slightly altered subwoofer placement to have the same maximized results.
If you want to maximize the results for the entire room, you’ll want to crawl around from a central subwoofer location to find the balanced bass lines.
That process will give you a compromise that’s useful for everyone.
■ Step #4. Check
When you have the correct placement (in your opinion) for your subwoofer, the best way to check it is to listen to the sounds.
Even after you’ve crawled around your room for an hour, you’ll discover that different environmental conditions can interfere with the listening experience.
- How does the subwoofer sound when your furnace is running?
- Can you hear the sub playing when the air conditioner is operating at its highest setting?
- When the kids are playing indoor basketball upstairs, does the ceiling vibration shift how you perceive the bass frequencies?
- If the wind is howling through the fireplace, do you lose some of the bass?
- When it gets hotter or colder outside, does the temperature shift create subtle changes to how the sound waves flow?
The different variables you can find in any subwoofer setup, with or without a sub out, make it impossible to guide someone to the perfect network remotely.
Even personal preferences can create alterations in placement and choice!
One of the best ways to maximize your setup check is to use a measurement microphone with a USB interface to analyze how the subwoofer interacts with the environment.
You can use an EQ program on your computer with this information to see if improvements are possible.
Another option is to use a real-time analyzer on your smartphone. These apps require you to play pink noise, which you can access via YouTube, to see how smooth your bass response is throughout the room.
You should feel the vibrations in your chair or couch when a movie has an explosion. When there’s a bass solo in your favorite song, it should feel like the instrument is in the room with you.
Although checking for these dynamics is lots of work, you’ll find that the results are often worth the effort.
If you don’t believe it, just shut off your subwoofer after you finish the connections. That’s proof that your hard work matters.
■ Step #5. Combine
If you want to maximize the listening value in any room, it’s usually better to run two subwoofers with your audio system instead of one.
Although that decision increases your setup cost, it’ll give you a more consistent bass response and a smoother listening experience.
The best setup with two subwoofers in a standard room is to place one sub at the front left corner. You’d put the second one in the front right corner.
When everyone in the family thinks of themselves as audiophiles, you might want to go with four eights as subwoofers instead of two 12s.
When you place a sub in each corner, you’ll get the smoothest bass and most consistent sounds.
You could put two subwoofers in opposite corners, but it typically doesn’t provide a better experience than placing them in the front.
Since the prices of subwoofers have been dropping rapidly over the past few years, it is affordable to get two budget-friendly subs instead of purchasing a single one.
The one exception to that rule involves the single listener. If you’re the only one who will be using the equipment, a larger sub with proper placement does better than multiple ones in the corners.
It is usually better for everyone else to buy two smaller ones than one large sub to generate the sounds you want to hear.
When you really want to get the most bang for your buck, consider adding a subwoofer equalizer to correct the audio to account for the other speakers’ flaws.
Don’t forget! If you want more than one subwoofer, always get two or more of the same make and model to receive consistent results.
Are You Ready to Get Your Subwoofer up and Running?
Although the price isn’t a determining factor when purchasing a subwoofer, you’ll typically get more quality from a premium unit than an entry-level one.
The other thing I’ve learned about using a subwoofer without a sub output is to go wireless with this technology.
With Bluetooth connectivity and smart entertainment systems, you can avoid the issue altogether.
That’s why my preferred subwoofer is the Sonos Sub Generation 3. It delivers a deep bass, minimal humming, and almost zero vibration.
That means you get a full-bodied sound without the distortion that comes from other high-level models.
It’s worth the investment. You’ll receive theater-quality sound from the moment you finish the installation.
When you follow the installation techniques outlined in this guide, you’ll never need to go anywhere to listen to your favorite playlists, podcasts, or TV-based entertainment again.
It’s been a life-changer that earned my full recommendation.