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.Contents
Home stereo subwoofers explained
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
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.
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
1. Connecting a receiver to a subwoofer with RCA input jacks
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, also called speaker level converters or “hi-lo converters”, are small adapters that accept speaker wire connections and scale down the speaker level signal to a low level signal (RCA jack) type output used by amplifiers. 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 are still really useful there, too.
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?
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
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. Generally speaking, 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.
Most speaker to line level adapters have a relatively high input impedance (resistance), which will only have a marginal effect on the total speaker Ohms load seen by an amp or receiver. However, a few do have lower input resistance that can potentially cause an issue so they’re best avoided.
Note #2: For best results, I recommend (when possible) using a speaker level adapted with an input impedance specification of 60 to 80 Ω or similar. Lower ones (ex: 16 ohms) can drop the total speaker load by several Ohms when used in parallel.
3. Using a mini amplifier for passive subwoofers
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.
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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.
4. Connecting receiver speaker outputs to a passive sub
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
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.
I used your “Option-3” to repurpose a set of older Samsung theater system speakers and subwoof, and it worked perfectly. As I’m using a Sony STR-DH190 amp/receiver, I wired the main speaker set to the A bank and gave the LOC-80 the B bank all to itself.
I’m still experimenting with the main volume and base volume settings on the Facmogu. But all in all I’m really satisfied with this set up. Thank you!
Hey Dwayne, that’s wonderful to hear! Thanks for the feedback and enjoy your sound setup!
My subwoofer is just a big Kenwood black box with a negative and positive speaker wire hook up. The problem is my new sony surround sound amp has a subwoofer output put using RCA plugs + and -. I cut the end off a dual one and fed the cut off end to the speaker. Should that be working?
Hi, it sounds like you have a surround sound amplifier with an RCA output(s), which means you’ll need an amplifier to power the amp. You can do that one of the ways I mentioned in my article.
Many receivers, for example, don’t power a subwoofer directly – they usually only have a line-level amplifier as many home theater subwoofers are self-powered.
Hi Marty.
I come across your article and was wondering if you would be willing to offer some help in regards to a Yamaha RX v361 home amp which is part of a surround sound system. I recently re-wired my house and wired in 5 speakers cables and forgot the connection between the amp and subwoofer. On the back of the powered sub I have a left and right rca inputs. Is there a way of connecting the sub with speaker cable that I have run to the area where the sub is ti the back of the amp?
Hello there, Tony. Yes, you can certainly do that as shown in my article by using a line level converter to get an RCA signal pair from your speaker wiring.
You can connect one near the subwoofer and run speaker wire to the line output converter (LOC) as needed where convenient. You can connect it to either unused or currently used speaker wire pairs if you like – it won’t hurt the amplifier.
Best regards and let me know if anything isn’t clear.
Hi Marty.
Thank you for coming back to me.
I have only a single speaker cable going back to the amp like the rest of the speakers.
I have looked at the converter and there is 2 pairs of connections coming off it.
Is there somehow I can send you some pictures so that you get a better idea?
Hello. In that case, you can use only one side of the converter – the other side won’t have to be used. I didn’t realize you have only 1 pair of speaker wiring available.
Best regards.
Hi Marty
So something like this below?
CP Line output converter, Hi to Low level adapter, Speaker to RCA converter, car audio converter, Premium product, comes with Instructions and technical assistance. https://amzn.eu/d/151Y3kt
Hi Tony. I don’t recommend that particular model, as when I took frequency response (audio performance) measurements of several different models, the one I tested that was very similar did poorly. You can see a graph of what I mean here in this image in my article about line output converters. (See the figure for “KY K-28”)
A better option would be this Kicker LOC with a flat response, although it costs a bit more (I cannot seem to find their cheaper version on the Amazon UK site.)
If price is an issue, then yes you could make due with the one you linked to. It’s a cheaper one, but at least it has adjustable outputs which can come in handy sometimes.
Hopefully that helps! Best regards.
Hi Marty.
I’m happy to purchase the recommended one you have said.
I’m just wondering with the cables coming off the converter, how would I join them to the single speaker cable I have.
I see coming off it that there is a few input cables and I don’t want to wire it up incorrectly.
Thanks again.
Hi Tony. If you only have one pair of speaker wires to connect to you can just connect one pair (input side) from the LOC to that.
Optionally, if you need two RCA outputs, you can connect both the left & right speaker inputs on the LOC together to the one speaker wire pair. Best regards.
Hi Marty.
Not sure if my reply went through the last time.
I don’t mind spending the extra if it’s going to work.
Just abit worried about wiring it up correctly as there are a few cables coming out and as I only have a single speaker cable, how would be best to wire it up.
Thanks again for your support.
Hi Tony & sorry for the delayed reply – I traveled a bit this week so I’ve been a little bit distracted.
I responded to your previous comment. Don’t forget that you can reach out directly via my Contact page (see the top menu) if you need to.
Thanks!
Hello, I have a passive sub ( newbie DIY home theater) with speaker wire connection that I need to hook up to my Denon AVR S760H rca sub out. Do I need an external Amp or a line level ?
Hello Chris. You will need an external amp and connect to the line output that way. You can use a small amplifier like this one to do this affordably and easily.
Best regards.
I’m new to your site but I read A few of your articles I enjoyed the simplicity of how you made it for someone that needs help. Thanks again for your help to all 👍🏽
Hi there Paul. Thank you for the kind words and I’m very happy that you found my website helpful!