How To Connect A Subwoofer To A Receiver Without A Subwoofer Output

Got a subwoofer with no sub output handy? Don’t worry – there are several simple ways to connect a subwoofer to a receiver without a subwoofer output.

Read on and I’ll show you several options along with easy and clear diagrams to help.

Update! Based on reader feedback I’ve added more info about passive subwoofer use. The diagram is also updated & improved.

Home stereo subwoofers explained

Passive vs active home subwoofers diagram

Comparison of non-powered (passive) vs powered (active) home stereo subwoofer enclosures.

Home stereo subwoofers are available in two different types: powered (“active”) and non-powered (“passive”).

  • Powered subwoofers use a low-signal signal that is boosted using a built-in amplifier, power supply, and output only bass using a crossover. These types are one of the most common and in many cases use an RCA type input jack to connect to the receiver for sound.
  • Passive (non-powered) subwoofers are simply a subwoofer speaker inside a bass enclosure.  It’s wired directly the speaker terminals or through passive bass crossover inside in some cases. These types are less common.

How a subwoofer produces bass

The subwoofer works by resting inside of a speaker enclosure where bass frequencies are captured as the woofer cone movies, producing deep bass sound. 

In order to produce clean-sounding bass without vocals or other sounds a subwoofer can’t properly produce, a low-pass crossover is used. The problem comes when you try to connect a subwoofer to a signal without a crossover – it sounds terrible!

The subwoofer output jack on a receiver is normally limited to passing bass only, either from stereo music production or from the “.1” subwoofer channel (dedicated subwoofer music content) of a surround sound system.

For example, when you hear references to “5.1” or “2.1” speaker systems or surround sound audio for movies, the first number represents the number of main speakers. The “.1” is used to represent a sound channel limited to optional subwoofer use.

Powered subwoofer inputs & controls you may (or may not) have

Powered subwoofer example with inputs and controls labeled

Example of a powered subwoofer with 2 types of signal inputs (speaker level and RCA jacks) along with sound controls. Note: Not all subwoofers have speaker level inputs, which makes it a problem connecting them to a receiver without a subwoofer output.

Powered subwoofers usually have several inputs and controls but it always depends on the brand and model. Here’s an example of what you’ll usually find:

  • Power input (AC outlet power)
  • On/off switch
  • RCA input jack or a pair of jacks
  • Subwoofer crossover frequency adjustment
  • Subwoofer level adjustment know (the amplifier’s gain [boost] level)

The subwoofer input jack usually connects to a single mono output jack on the receiver, although some models provide stereo RCA inputs but can usually work with just a single mono connection. Mono (monaural) subwoofer output jacks combine both stereo channels into one so that no sounds are lost like can happen with only using the left or right side signal.

Receiver subwoofer output jack example

Example of the mono RCA subwoofer output jack found on many home receivers. These connect with a single male to male RCA cable to a powered subwoofer.

Some models also include speaker level inputs meaning they can be used with any modern or old home stereo receiver without a subwoofer output.

While that’s nice, if yours doesn’t have that feature, ordinarily you’d need to buy a different subwoofer and waste money.

In fact, some of the information you’ll find right now on the internet says that you have to buy another subwoofer if you don’t have a receiver with an output jack. That’s simply not true.

As I mentioned at the beginning of my article there are several ways to work around this problem.

DIAGRAM & EXAMPLES: Connecting a subwoofer to a receiver without a subwoofer output

Diagram showing how to connect a subwoofer to receiver with no subwoofer output

1. Connecting a receiver to a subwoofer with RCA input jacks

Example of a powered subwoofer RCA jacks & RCA Y adapter cable

Left: Example of a powered subwoofer with 2, instead of the typical 1, RCA input jacks. Right: An RCA Y adapter that can be used with a line level converter to connect to a subwoofer with a single RCA input jack.

For subwoofers with only 1 or more RCA input jacks (no speaker level inputs), a simple way to connect them to a receiver with no subwoofer output is by using a line level converter.

What is a line level converter, and how do they help?

Line level converters are small devices that accept speaker wire connections and scale down the speaker level signal to a low level signal (RCA jack) type output that the subwoofer can accept. They’re extremely handy in the car stereo world because they make it possible to connect a stereo without RCA outputs to any amplifier.

They’re not commonly used for home stereos but still really useful there, too.

Image showing examples of line level RCA converters

Shown here are two examples of line level/RCA speaker level converters that work well for home receiver/amp to subwoofer use. A line level converter takes the higher voltage speaker signal from an amplifier or home receiver and scales it down significantly so it’s safe to use with RCA inputs.

How much do line level converters cost?

A quality line level converters have a price range of about $15-$25 each. They’re connected to the speaker outputs of a radio, receiver, or amplifier. RCA cables are then connected to the jacks provided. The internal electronics not only scale down the speaker output voltage from a receiver but also help prevent noise from the audio path, too.

If you’re using a subwoofer with a single RCA subwoofer input jack, you may want to pick up a “Y” RCA adapter to combine both receiver channels on the output side into one.

Subwoofers with 2 (stereo) RCA jack inputs, however, are fine using standard male-male RCA cable pair.

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2. Subwoofers with speaker level inputs

Example of subwoofer speaker level inputs

If you own a subwoofer with speaker level inputs you’re in luck! You can connect these directly to your receiver’s speaker outputs, either by themselves (on unused speaker terminals) or at the same time with speakers connected to the receiver.

Subwoofers with this feature contain internal electronics that scale down the speaker signal from the receiver before it reaches the internal amp that powers the sub. It’s just a line level RCA converter already provided, essentially.

Additionally, there’s a low-pass crossover built in as well to produce great-sounding bass and no unpleasant parts of the music – just pure, low-end bass.

Connect these directly to the receiver just like you would another pair of speakers, either on unused speaker outputs. You can connect these to receiver speaker outputs already in use as they will not bring down the total Ohms load the receiver or amp sees.

Note: Subwoofers with speaker level inputs and outputs provide a way to easily connect both at the same time. The outputs are internally connected to the input connectors, making it easier to add speakers and the subwoofer to a receiver simultaneously.

3. Using a mini amplifier for passive subwoofers

Example of a 2.1 stereo mini amplifier with sub output

When wanting to add a single voice coil (SVC) passive subwoofer, several issues come up. Hands-down, the simplest solution is using a mini amplifier with a mono low pass subwoofer speaker output.

For this setup, you’ll do the following:

  • Use a line-level RCA converter to get an RCA signal to the amplifier.
  • Connect the passive sub to the subwoofer output.
  • Use the AC-DC power supply to power it.

That’s pretty much it! Having a built-in sub crossover means the sound will be nice, clear bass without vocals much like a self-powered subwoofer provides.

Today’s small amplifiers are typically very compact in size as many use an efficient class D amplifier design. They’re sometimes called a 2.1 amplifier as they usually have both stereo speaker outputs and a dedicated subwoofer channel.

Facmogu ST-838 2.1 Mini Amplifier With Subwoofer Output
20Wx2 stereo + 40Wx1 subwoofer output. RCA and 3.5mm input jacks. Easy to use speaker terminals. Bass, treble, and volume controls. Includes power supply.

Cost and other notes

They cost around $35 to $50 or so depending on the model. The downside is that if you want a ton of power, they’re not the best choice as many offer about 35W to 68W sub power. If that’s not enough you’re better off getting a more expensive amplifier.

Note: Mini amplifiers may or may not include the power supply so be sure to check when shopping.

4. Connecting receiver speaker outputs to a passive sub

Example of a passive subwoofer low pass crossover

Example of a passive subwoofer low-pass crossover. Passive crossovers, unlike electronic crossovers, work using capacitors and inductor coils instead of electronic components.

If you’re wanting to use a non-powered (passive) type of subwoofer, there’s still hope, although it can be a bit harder to find the right parts and set up vs using a powered subwoofer.

To use a non-powered subwoofer, as shown in my diagram above, you’ll use a low-pass subwoofer speaker crossover which is connected between the receiver and the subwoofer enclosure. These filter out higher frequency sounds before they reach the sub to help provide clear & nice-sounding bass only.

How to choose a subwoofer crossover and where to find them

Speaker crossovers like this are sold single channel (one speaker) or dual channel (2-speaker) models, depending on the brand & supplier. They also have to be matched correctly to the impedance (Ohms rating) of the sub.

For example, subwoofer crossovers designed for 8 ohm speakers must be used only with those. Otherwise, the sound filtering is radically different and won’t sound as expected since the crossover filter is based on the expected speaker impedance.

For example, you can’t correctly use an 8 ohm sub with a 4 ohm crossover.

Normally you’d choose one with a low-pass frequency of close to 100Hz or in that range. Speaker crossovers are sold where speaker parts & related components are sold as well as marketplaces like Amazon or Parts Express.

Stereo vs surround sound receiver subwoofer output differences

Stereo vs surround sound receiver differences diagram

Unlike older or standard stereo receivers, surround sound receivers have a unique output that comes from the surround sound movie or music source. However, in regular stereo listening mode, they act the same as regular receivers.

One thing to bear in mind is that when connecting a subwoofer to a receiver without a subwoofer output, you can’t get a convenient “.1” bass channel like can with surround sound receivers.

On the other hand, it may not even be an issue. In fact, the surround sound receiver “LFE” (low-frequency) output is considered optional – hence the “.1” name. There is a drawback, though: for some movies, especially action or other types, movies and music in surround sound can sound even better.

While using a regular receiver to connect to a subwoofer means you can’t get quite the same effect, the good news is that in stereo mode, both new and old receivers have very similar subwoofer behavior when connected as you’ve seen here.

Also, listening to a surround sound movie through a stereo connection to your standard receiver is still good. For stereo, surround sound tracks are downmixed, meaning all the sound information is mixed into the two channels.

You’ll still get the same bass signal available that you can use to supply your subwoofer.

More helpful speaker info & diagrams

I’ve got lots more information to help you get your sound system going:

Your comments are welcome!

  1. Hello Marty,

    Happy New Year!
    I have just added an Elac powered Subwoofer to my Sony DH 590 receiver.
    I have surround sound speakers, so changed receiver setting from 5.0 to 5.1.
    Sony TV is routed through the receiver as well.
    My issue is that the Subwoofer doesn’t work when watching or listening to music from TV.
    But it does work when I transmit music to the receiver via Bluetooth . Any suggestions?

    Reply
    • Hi Eric and Happy New Year to you, too! :D

      I believe what is going on here is that when the receiver is in stereo mode, there’s no “.1” signal to pass to the LFE (subwoofer) output. I’ve had this happen as well. What you’ll want to do is check the options for your DH590 reciever as in most cases there’s an option to route bass to the subwoofer output when it’s not in surround sound mode.

      There are usually some sound field options that will work. Unfortunately, it can be a bit odd how receivers handle this, but 99% of the time this is just a matter the settings. If yours has Pro Logic II support built in (home theater receivers that support Dolby Digital almost always are backwards compatible with Pro Logic) you should be able to set it to that and it will work.

      When a 5.1 signal is passed then it should switch over to the digital surround sound instead in most cases. This stuff is kind of an odd thing that isn’t explained or documented well, sadly. A lot is trial and error.

      Best regards.! :)

      Reply
  2. Hi Marty,
    Happy new year,
    I have a question for you.
    My dac has an XLR and an RCA output. I connected my amplifier (which doesn’t have a sub out) to the XLR output of the dac and my subwoofer to the RCA output. Obviously the DAC does not have a crossover and I only adjusted the low pass filter of the subwoofer. Do you think this is okay? Or should I add something in the chain?

    Reply
  3. Hi Marty, if my Sony amplifier only has RCA subwoofer outputs and I have a passive subwoofer, with wired positive and negative wires, where should I plug it into? I know the RCA jack won’t power it so all that is left are the other speaker terminals. When I do use for example the front right terminal to connect it the subwoofer works but it is actually producing bass and doing its job? I would assume the RCA subwoofer output is where it needs to go for the bass but that won’t power it. What is your recommendation and am I doing this correctly? Any advice would be much appreciated!

    Reply
    • Hi Chris. The problem here is one that some people run into and it’s that (1) you need amplification to power the subwoofer, and (2) you need a low-pass filter to ensure the subwoofer gets only bass and not midrange, etc. The RCA output is just a line-level signal (very low voltage) that needs an amplifier of some type.

      One convenient way to deal with this is to use a mini amp to power the subwoofer (it has a crossover built in). Have a look at ex. #3 here: https://soundcertified.com/how-to-hook-up-car-subwoofer-home-stereo/#How_to_wire_a_car_subwoofer_to_a_home_stereo

      I’m going to update this article to add that info as several people have mentioned similar things just like yourself. Thanks!

      Reply
      • Thank you Marty! I found this one, will this be ok:

        Wireless Bluetooth Stereo Mini Amplifier – 100W Dual Channel Sound Power Audio Receiver USB, AUX for Home Speakers with Remote Control – Power Adapter Not Included https://amzn.to/31M8btQ

        I just need to buy the power adapter for it as well.

        Reply
        • Hello again, Chris. That one will work, but it’s full range so you’ll still need a subwoofer (low-pass) crossover of some type. You can use inline RCA crossovers if you like, but the one I mentioned (Lepai LP-168HA 2.1) has it built in already as a dedicated sub (mono) output channel.

          You might also have a look at the Facmogu ST-838 at Amazon as it’s essentially very similar to the Lepai 2.1 and has the subwoofer output built in. It’s not high power but will be a good start.

          Alternatively, you could use a budget 2 channel that can be bridged to do the same thing. You might even find it easier to use a cheap/2nd hand car amp and a 12V supply to do this. Most car amps have a crossover feature while many home stereo amps don’t.

          Reply
  4. Thanks a lot for the article. I have a question regarding the line level converted. Say I attach it to my integrated amp, and then the output of the converter to my sub (as shown in the diagram), would, when I alter the volume on my amp, the sub volume be altered accordingly?

    Reply
    • Hi Camille and thanks for writing. Yes, the volume will change accordingly. A line level converter just scales down a speaker level signal to a low-level (line level) signal, so it will still adjust accordingly with the volume output.

      Best regards! :)

      Reply
  5. Hi! So I just got a used Onkyo HT-R380 receiver and it has a passive sub output and I didn’t notice that at first and I have the Klipsch reference theatre pack 5.1 system with a powered sub with 2 RCA connections (L/LFE+R), gain knob, Low pass filter knob, and a phase switch. Would a high to low level converter work in this situation even though the receiver already has a mono subwoofer connection, just at a high level? Would I just connect the +/- of each L+R inputs on the converter together?
    Do they make mono high to low converters? I’ve tried searching and can’t find anything on it. Any tips will be greatly appreciated!

    Reply
    • Hi Hyrum. Yes, a line level converter will do the trick fine if your sub doesn’t have speaker level inputs. You can use just one side of the line level converter in this case because the Onkyo’s subwoofer output is already mono, making things a bit easier for you already (as opposed to stereo outputs).

      I don’t recall seeing mono converters unless it’s a rare case of them being pretty basic ones sold separately, but personally I’d go with a brand name – doesn’t have to be expensive, but not the el-cheapo stuff as those can be a bit crudely designed.

      You can also feel free to combine the + and – speaker wiring inputs as you mentioned, but you’ll still only need one of the RCA outputs. Just ignore the other one. You can also add a 2nd powered sub later if needed pretty easily.

      Reply
  6. Hi Marty,
    I’m no expert about sound system, I have amplifier with 2 pairs speaker output which I use only 1, I’m willing to use the other output to active sub. is it safe to do that? what is the worst case? will it damage my amplifier or sub if I connect to wrong output? does plus/minus or red/black port matter?
    Thank you

    Reply
    • Hi, it’s perfectly fine to use the unused (or even already in use) speaker outputs to an active/powered subwoofer. You do want to be consistent with the polarity, but that’s in order to be sure the input signals are “in phase” and don’t cancel out audio signals. This is both for using a line-level adapter or speaker level inputs.

      A line-level adapter or speaker-level inputs have pretty high impedance (resistance), often on the order 1,000 ohms to 1OK ohms or so, so there’s ordinarily no way to hurt your speaker outputs. It’s also why you can connect a subwoofer’s signal inputs to speaker outputs already in use – to the amp or receiver, it’s as if there’s no extra load at all, essentially.

      The speaker outputs will just be used for a signal, not drawing power, when going to a powered sub. So just wire everything properly and there should be zero issues. (Different story when we’re talking about non-powered subs)

      Reply
      • Wow…. thanks for fast response

        You said the speaker output just send a signal, not power. How come my passive speaker can have loud sound?

        one more question, my sub have 2 input rca (L/R), someone on internet says you need only one (mono), is it true?

        Thank you very much.

        Reply
        • Hi, well not quite exactly. For speakers, yes, an amplifier or stereo etc. does supply to power them. But when connecting to a speaker level adapter or speaker level inputs on a powered speaker, there’s no real power draw. The speaker signal is just scaled down to a very low level and goes to whatever amp is inside the powered speaker.

          For the RCA inputs, usually just one works fine. It depends on the design. Some are marked with a mono input and some are better with L *and* R. The left input is often the mono one in that case.

          If you have a Y cable or stereo RCAs handy you can try one vs. both and listen to see if you hear more sound with both in use. If not, it’s fine with the mono-only input. It’s most likely mentioned in the owner’s manual anyway.

          Reply
  7. Hi Marty,
    Great article and this is exactly the issue I’m trying to figure out. I have a Denon AVR-S750H with 2 sub pre-outs. I have 2 Klipsch RW-12’s & 1 R-100 and was looking to add a 4th soon. Just got the R-100 delivered and used a y-splitter off my Denon to connect the 2 subs but 1 is only producing sound. I called Denon and they told me that that receiver doesn’t support a y-splitter. Would this line level converter be the thing I need to get my room wired with 4 working subs?
    Thanks very much for yr advice.
    John

    Reply
    • Hi there John. I’m not clear on how you connected them but I’m not aware of any reason that won’t work. For example, assuming preout 1 & 2 are both functional you could run one RCA from out 1 to a Y splitter and then to each RW-12. Then from #2 to the LFE input on the R-100SW (and later a Y adapter there also for the 4th sub, just like the first 2).

      You can always fall back on using a line level adapter to the subwoofer speaker outputs if you like but I don’t think that would be necessary. Have you tried both sub outs 1 & 2? They’re both working? Or how did you connect everything?

      Best regards.

      Reply
  8. Hi Marty,

    Just added a new Sony subwoofer to my old Denon stereo using the subwoofer output plug. Working OK but..

    Bought the house. Inherited the speaker location.

    The A speaker has 3 sets of ceiling speakers with Lpads for volume adjustment and requires the receiver to be turned up very high to work. Too high for the B speakers and that’s where I want to listen with the subwoofer. So I assume the subwoofer plays all the time regardless of speaker button choice so I will have to turn it off when switching to the A speakers because of too high volume issues? Or not. And when the A speakers are on only will I still hear the subwoofer in the B speakers room even if the amp doesn’t increase the volume to the receiver subwoofer jack output?

    Ideally would like to have both A and B speakers and the sub have balanced audio outputs so I can listen to anything without worrying about wrecking a speaker.

    Have considered speaker wires from my B speaker terminals so they go only to the subwoofer. Have thought about one more Lpad attenuator on the B speakers for A and B balance.

    Whew. Thanks!

    Reply
    • Hi Roger. Yeah, sounds like a pretty annoying problem and I can see what you mean. There’s more than one way to deal with it, although I don’t there’s a “perfect” solution to the problem.

      1. If you were to have a subwoofer in the room/area near speaker set A you could place a subwoofer there and use speaker level connections to it. Then similar for set B. The bass would be proportional, but you’d lose the subw output use from Denon.

      2. You could add an amplifier to power only speaker set A and get more power to them for more volume and match set “B.”

      3. (last option which is the one you mentioned regarding adding L-pads to speaker set B).

      Of the three, #3 would be the easiest and lets you keep using just one subwoofer. You’d need L-pads with a power rating sufficient for your stereo of course. I think that’s worth a try, assuming the reduced volume for set “B” won’t be a problem for you. Also should cost a lot of money, either.

      Best regards!

      Reply
  9. Hi!
    I have a yamaha with 2 channels and an active subwoofer with in/out speaker levels, can I use my subwoofer to add an extra pair of speakrs meaning I have 6 speakers four connected to amp and 2 connected through sub.

    Reply
    • Hi there. No I’m afraid not unless your Yamaha can handle the Ohms load for 2 sets of speakers in parallel. The “out” connections on the subwoofer are just passthrough connections for convenience.

      Best regards.

      Reply
  10. Hi please help
    Whilst tidying up some cables I think I damaged the pre out subwoofer terminal on my Onkyo receiver. The sub is no longer working. Is there any way I can wire the sub using other inputs on the onkyo receiver? The sub is a keff cube active powered and has 2 inputs, left and right line input using rca cables. I can’t afford to buy another receiver at the mo so any help would be greatly appreciated!

    Many thanks

    Reply
    • Hi there. You didn’t specify which model it is so I’ll guess it’s the 10B model? If so, yes you can use the speaker level connections and connect to existing speaker terminals (even if they’re connected to speakers already. See example #2 in my diagram above.

      That should get you going. :)

      Reply
  11. Hi Marty,

    My question is similar to some above. I have an old Panasonic subwoofer from a HTIB set up that I want to connect to a new Sony home theatre receiver. I know I have to connect my receiver to a mini amp via RCA to get signal to the amp and then connect my sub to the amp.

    The amp I am looking at has one RCA line in and two binding posts +/- out. My question is do I need to connect the red/black wires on my sub to the corresponding binding posts, or can I connect them both to one post (left) as it is a mono signal?

    I saw a diagram somewhere that showed only hooking up to one of the outputs but not sure if that is correct. Your thoughts are appreciated. Thanks!

    Reply
    • Hi Jason. The wiring will depend on the Ohms load the amp you’re talking about can handle and the speaker Ohms for the subwoofer(s). If the amp cannot handle the Ohms load with both subwoofer connections in parallel you could wire them in series and that should work ok.

      Generally speaking, stereo amp outputs will need to both be used for good sound (no sound missing from one channel) but if it’s truly a mono amp that shouldn’t be a problem. Again it will depend on the subwoofer as I don’t have much info to go by. Best regards.

      Reply
  12. Hi, great article and very informative
    I think you’ve answered my question but as this is recent and you seem to be replying i thought itd be good to get clarificatin from a man that knows!

    I have a BOSE Freespace III subwoofer that has a 100V feed from the amplifier. It’s got a built in transformer set to 100W for 4 x 100W low impedance satelite speakers which are connected. All works.
    Can i wire an ACTIVE/POWERED Subwoofer into one of the satelite/speaker connections? aka sacrifice a speaker for an additional subwoofer? assuming the subwoofer is rated 100W+ and powered by mains?

    It was installed around my house by the previous owner, the games room needs more bass as my music has a lot of it and just this one isn’t enough so i wanted to add 1 more, i cannot run a cable to the amplifier because it was done before the walls were plastered.

    Many thanks, James

    Reply
    • Hi James. Good news in two regards, not just one:

      1. Yes, you can use the speaker level signal to run into a powered subwoofer’s speaker level inputs (or a speaker to line level apdater for RCA jacks).

      2. You don’t have to sacrifice any speakers to do this. Speaker level inputs are high impedance meaning they can be connected alongside speakers already in use in most cases. They source amplifier won’t “see” a low impedance it’ll be as if nothing changed.

      Best regards.

      Reply
  13. Hi. Thanks for your through explanation on subwoofers.
    My setup would be like your example #2: ‘Receiver + Powered Subwoofer, with Speaker-Level Input.’

    Question: How far can the Subwoofer be located from the Receiver? I’d like to have my Subwoofer about 25 feet away from the Receiver. Using a Polk MXT12 powered subwoofer.

    Please advise.

    Reply
    • Hi Dan. That shouldn’t be a problem at all. 25 feet is reasonably close. In the case of speaker level inputs you’re only using the speaker signal, no actually driving power per se from the receiver.

      In fact, can use a small gauge wire if you like.

      Reply

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