How to Connect Subwoofer to Amp Without Sub Output

How to Connect Subwoofer to Amp Without Sub Output

Which should be more difficult to deal with? Running your subwoofer into a receiver or placing it in a suitable position in the room?

Most audiophiles will say that it’s placing it in a suitable position in your music room while some beginners may say connecting the sub to a receiver. In cases where the subwoofer does not an easy-to-figure connection jack, it takes a lot more time than positioning would. Usually, a sub just needs a power jack and an audio input jack.

A subwoofer can improve any sound that comes in contact with it. Home theaters, stereos, studio speakers, all need a subwoofer to boost their low-end sound. When connecting to a home theater, there are a few options depending on what brand of receiver and subwoofer you are using. Some subs require that connect to them using speaker wire or even stereo RCA. For most receivers, the option is to connect the sub to the receiver’s LFE output or to the SUB OUT. It’ll be easier for you to connect to any subwoofer if you have an amplifier that different connection jacks.

Prefer Videos? Here’s how to connect your sub to an amplifier without sub output

What if you are connecting a stereo system? Is there a spot for linking a sub if it doesn’t have a Sub Out? For certain stereo amplifiers, there is preamp out labeled “Subwoofer Out”. A stereo receiver of this type needs the crossover of the sub to set the high-frequency benchmark and the low-frequency pick up the sub will work with. This kind of receiver is a line-level signal that has a bandwidth that is full. A subwoofer that does not have the “Subwoofer Out” should have “speaker level” input which can also be called “high level” input.

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With the high level input, you can connect to the speaker jack on your receiver without draining power from the amp. This makes it easy for you to connect more than one subwoofer in your amp since the subs don’t need the amp to stay powered. You can even connect a six-line-array sub without affecting it. All the sub does is detect the signal and boost it.

Connecting a Powered Subwoofer to a Receiver

When you handle a powered subwoofer, there are two main connections you should sort out. They are signal and power connections. The signal it needs comes from a receiver or an amplifier. You have to connect the subwoofer and receiver with a subwoofer cable.

The power connection just requires an outlet that is close to the sub. The connection should be clean so that the sub doesn’t suffer from a power surge.

Connecting to a Receiver Using the Low-Frequency Effects (LFE) Cable

You’ll find more home theaters that have the subwoofer output tagged with SUBWOOFER (or SUB OUT). Even stereo speakers have this output jack. This makes it a more preferred output system when running a receiver to a subwoofer. Also, you need an LFE cable to run the connection from the SUB OUT into the LFE port of your subwoofer. On the subwoofer, an LFE port is tagged SUBWOOFER.

If the receiver you have is a 5.1 channel audio, you’ll find that it has a special port that is meant for bass output. This is the “.1” port. This port needs to be connected to a subwoofer with a single RCA cable. Run it through the SUB OUT of your receiver into the LFE IN port in your subwoofer.

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Connecting to a Receiver Through Speaker Level Output or the Stereo RCA

Now, this is why we came all the way. Because some subwoofers do not have that output jack (also called Low-Frequency Effects port). Or it’s the amplifier that doesn’t have the subwoofer output (also called SUB OUT).

For subwoofers, you may find spring clips that look like those of a regular loudspeaker. Either those or stereo RCA connectors (i.e. R and L stereo connectors). You’ll have to pair your sub with the specific port that works with it on your amplifier. Check whether the Line-In port on your sub is compatible with RCA cables and if the SUB OUT of your receiver can work with those cables too. If you are using a single RCA, just run the cable from any of the RCA ports on your sub into the subwoofer port in your amplifier. If you are using a Y connector then connect both ports to your subwoofer output.

If you have a receiver with double ports for SUB OUT, just like the sub, then use two single RCA cables to run the left port into the left port and the right port into the right port.

About subwoofers that use spring clips that require speaker wires, the SUB OUT of your amplifier will do just fine. It’s as if you are running a subwoofer into a stereo speaker but you have to connect the right channels carefully. There are two ways to run this connection. This depends on if the spring clips on the sub are single or double.

Double set of spring clips have a “speaker in” and “speaker out” clips. In that case, connect the speaker to the subwoofer in one clip and run the sub into the receiver. If the clip set is single, then you have to connect both the speaker and the amp in the same clip. Make sure the wires in the spring clip don’t touch themselves.

How Else Can You Connect Your Subwoofer Without an Out?

You may have an amplifier that allows you to adjust your speaker’s performance with a built-in calibration microphone. With this process, you can set the sound on your speakers to suit the need of your room. Without an automatic calibration system, you can manually set up your speakers the way it satisfies you. Even auto calibrations can be adjusted manually. Below are a few tips that you can employ to manually set up your sound.

Arrange Your Speakers on the Front Left and Right

The best way to run this arrangement is to place them from the smallest to the largest. Read through the producer’s guide because that will help you know how to go through with handling your sub. The setting of the speakers should be based on the output power of the speakers. Use a crossover setting of 80 Hz. You’ll find that setting your front left and right speakers to small, they give out better sound. Running a sound source with two channels doesn’t change this effect. Large patterns with main speakers are usually not friendly.

On the Settings menu of your receiver, identify where the speaker setup is located. The setting will indicate sizes that you can choose for the speakers on the front left and right. This setting indicates bass management and not the size your speaker has physically. Here, setting your speakers to ‘small’ means that they send only sounds with low frequency to your sub.

Setting Your Subwoofer’s Mains + LFE

If your front left and right speakers are set to large, then you can set the mains + LFE on your receiver. Use the receiver’s bass management setting to identify how you can deal with your sub. When you have figured it out, set up your receiver’s mains + LFE is such a way that it only sends low end sounds to the sub while the main speakers are set to large.

In some receivers, the bass out feature will let you set up your audio for two channels. Here the crossover settings do not feed off each other amongst other benefits. With this, you can set up your subwoofer to accept audio from two channels if that works for you.

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Set up with the Preamp Output

Without the subwoofer output in your subwoofer, connect with the preamp output. This jack is usually on the connection board behind the amplifier or receiver. You’ll find it labeled as “Pre-out”, in most cases. You’ll have to use interconnects to run the Pre-out of your receiver into your subwoofer. If the RCA jack of your subwoofer has only one receiving port, then a Y connector will do a good job of connecting the two devices.

Video: How to Connect Subwoofer to Amp Without Sub Output

Watch this video to see how to connect subwoofer to amp without sub output

Connecting the Subwoofer and Receiver with Speaker Wires

You already know that you can use speaker wires to run the receiver to the subwoofer so that the sub acts like a speaker. Use the front left and right speaker terminals on your receiver for this connection. Run from those to the subwoofer’s speaker terminals. Also, run the front right and left speakers into your sub. In most cases, the speaker terminal you find on the sub will be a speaker level input. If you are yet to get a sub and you are not sure, ask questions before you close the deal.

If you ever have to connect through the stereo preamp level, you’ll need to leave LFE mode on your subwoofer.

A Few Terms to Note


Once you set the size of your speaker, you have set the point of crossover. However, the crossover point can be manually adjusted. The crossover point you set will depend on the kind of speaker you’re using. You can go as high as 120 Hz and as low as 60Hz.

Level Control

For a number of subwoofers, you can adjust the volume on their control panel. That way, you can adjust the volume from a soundtrack if the reflection from your sub is too loud.

Phase Switch

For a sub that is not syncing with other speakers after every necessary set up, you may check the phase switch. You’re likely to find a phase switch for two positions behind which, if you toggle, may improve the bass output of your device.

A Platform for the Subwoofer

You can always manage the reflection of sound from your sub by placing a sound absorber under the subwoofer (i.e. dampen the vibration). This will help to control unwanted sound reflection from the walls or floor.

Bonus. The Right Place for Home Theater Sub

Close to those front speakers, that’s where your sub should be. Not that there is anything wrong with keeping it anywhere that is more suitable. The sub produces a non-directional sound so you can always measure out the best place to keep it in your room that is not beside the front speakers. They’ll do well regardless. The trouble with placement usually comes with placing the sub close to a wall or in a corner. When the walls reflect the bass, it won’t be so pleasant if there are standing waves in the room. If it works well, the walls help to amplify the sound. You can always avoid standing waves by keeping the sub a few inches away from walls and corners.

Yes, you can test run a few positions from your favorite sitting spot. A friend always comes handy when you’re fixing the position for your sub. Play a favorite soundtrack with deep bass with your sub sitting in your fav place. Listen around to know where the reflection is best.

You can decide to actually move the subwoofer around. That works too. For each post that you place your sub, run your auto calibration again. However, placing your subwoofer in one place is an easier option. In the position where you get the best bass thumps, put your subwoofer there.

For large rooms, you may need at least two subs since the bass from one could easily trail off in the space. A second bass will help make sure that the sound goes round equally in the room. If you’re getting a subwoofer, you can find one that has two output jacks that you can connect to. If your sub doesn’t have one, a Y adapter will help you achieve that result.

Sort Out Your Stereo

When dealing with music systems like the stereo, the subwoofer out is not always a better choice for connecting a sub. Subs that use speaker level input work best. The speaker level jack on the sub allows you to connect to the amplifier in the same space as your main speakers without having to overload it with power demand.

A tip. When you check out subwoofers for your stereo system, focus on those ones that are built for articulation and speed. They should be able to bring out clean bass at very low frequencies. For example, they should faze off at 20Hz. The thing with sound speed from subs is the ability of the cone to stop vibrating when the signal is cut off. Good subs should also be able to receive signals fast enough even though the signal has to travel through a few phases before it reaches the speaker cone. If you find a subwoofer with these qualities, you have found a treasure for your music system.

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