How To Hook Up A Car Subwoofer To A Home Stereo (With Diagrams!)

How to hook up a car subwoofer to a home stereo featured image

Thinking about putting that extra car sub to good use? Maybe you’re wondering if it’s possible to hook up a car subwoofer to a home stereo or amplifier at all.

The good news is that yes, in many cases you can use a car sub with a home stereo. However, it’s not as easy as just wiring them up any old way.

I’ll tell you what you need to know and provide some helpful diagrams. Let’s get started.

Contents

Can I hook up a car subwoofer to my home stereo?

Can I hook a car subwoofer to a home stereo? Man thinking image

The quick answer is that it depends. There are several basic things you need to understand first before you try. These are important, too…so don’t be careless or you could damage your home receiver or amplifier.

You can hook up a car subwoofer to a home stereo directly if:

  • You have a subwoofer or more than one subwoofer that can be wired for at least 8 ohms total. This can be two 4 ohm subwoofers or a 4 ohm dual voice coil (DVC) subwoofer.  [See diagrams below for how] 
  • Your home stereo or amp can handle 4 ohm speakers (most can’t so let’s ignore this).
  • Using workarounds: this includes using a small 4-ohm capable amp between the receiver and sub or an inline resistor to bring up the speaker load. (Don’t worry – I’ll share these in detail below)

Even if you have the right car subwoofer(s) your amp needs to have enough power available to drive the subwoofer box. The good news is that for casual listening you don’t need a ton of power like you do for cars and truck use.

The single biggest obstacle is that most home stereos, home theater receivers, and home amplifiers can’t handle the 4 ohm speaker load of many car subwoofers. It’s 2x lower than the 8 Ohm minimum most require. (Some car subwoofers are even 2 ohms, in fact).

Why can’t I use a 4 or 2 ohm car subwoofer with a home stereo?

Diagram showing how to match speaker ohms to a home stereo

You’ll need to be sure to avoid connecting a speaker impedance (Ohms, speaker load) that’s too low to a home stereo amp or receiver. Doing so causes it to try to produce more electrical current than it’s designed for. This causes overheating and potentially permanent damage to your electronics.

Just like car amplifiers & car stereos, home stereos have a minimum speaker load, stated in Ohms, that they’re designed to handle. 

Never try connecting 2 or 4 ohm car subwoofers or speakers to a home stereo – they’re likely to overheat very quickly and suffer possible damage.

Why is matching speaker impedance important?

Matching the speaker load to your home stereo just means matching it up with the best Ohm load that will deliver the power & volume it’s designed to produce. As you can see in my diagram above, if the speaker is over the rated Ohm spec, it will work safely but at the expense of delivering a lot less power and volume than you’d like.

Using the correct Ohm load means you’ll get the rated power – and as you might guess – the maximum volume possible. 

However, using less than the rated Ohm speaker load (whether 1 or more speakers, the total Ohm load the stereo sees) is dangerous and won’t work. Don’t do it!

Tip: In cases where the subwoofer is less than 8 ohms total and/or the receiver or amp doesn’t have enough power don’t give up! There are some work-arounds that can you can use as we’ll see.

Do I need a speaker crossover for a car subwoofer?

Example of a passive subwoofer low pass crossover

Example of an 8-Ohm compatible low-pass speaker crossover for blocking all sounds above a low bass frequency (cutoff frequency). These are used to get “clean” sounding bass from a subwoofer when there’s no crossover already provided.

By the way, there’s another important part you’re likely to need and may not have thought about: using a speaker crossover for clear bass with a car subwoofer. Car subwoofers are normally used with a car amp with a low-pass crossover built in already.

That’s often not the case for home stereos, although some do have a subwoofer RCA output jack for use with an amplifier or powered subwoofer.

Diagram showing a passive subwoofer speaker crossover

The point is that unless you want to hear vocals and other sounds from the car subwoofer, you’ll need to hook up a subwoofer speaker crossover between the stereo & the sub. For clear bass, you’ll need a crossover to block higher-frequency sounds subs can’t play well.

If you’re lucky enough to own a receiver or home amp with a low-pass crossover built in you can use that instead.

How to wire a car subwoofer to a home stereo

How to connect a car subwoofer to home stereo diagram

As you can see from my diagram above, I’ve come up with 4 ways to connect a car stereo to your home stereo receiver or amp – but it greatly depends on the specifics. For example, using a 4 ohm car sub is relatively simple, while using a 2 ohm or another type can be more complicated.

Here are the  4 ways you can do this:

  1. Two 4 ohm car subwoofers: This is one of the simplest setups possible. Just connect the subs in series for a total of 8 ohms and connect them to one of the stereo receiver speaker outputs. However, be aware that if there’s no speaker crossover in place or built-in, you’ll get vocals and sounds in the subs that won’t sound good, so a crossover may be needed. (see above)
  2. Single DVC 4 ohm subwoofer: Likewise, a single dual voice coil (DVC) subwoofer with 4 ohm windings can be wired in series to meet the 8 ohm requirement. Just like above, a low-pass (subwoofer) crossover may be needed.
  3. Single 4 ohm subwoofer or receivers without enough power – using a mini amp: You can use an affordable miniature amp to drive a 4 ohm car sub directly, avoiding the needed to lose power like you would in option #4. You can use a mini amp that can drive a 4 ohm or even 2 ohm car sub directly. Some also have a built-in crossover for great sound making them a great choice.
  4. Single 4 ohm subwoofer using a series power resistor: This is the simplest and most affordable option. Using a power resistor (a resistor that’s designed to handle higher power levels) just wire it in series with the sub to get the 8 ohms needed. Power resistors can be found for around $5 more or less. I recommend a 25 watt or higher rating, depending on your stereo’s power output.

Note that while option #4 is the easiest of all, I don’t recommend it because you’ll lose 1/2 or more of the stereo’s power output. That’s because the power is divided between it and the sub. 

Audio power resistor examples

Examples of power resistors you can use for speaker projects including hooking up a sub to a home stereo. These resistors can be found and electronic parts stores and speaker part retailers, or even Amazon or eBay. They’re often priced very affordably (around $5 or so for a pair or pack).

What to do if you can’t get the right Ohms together

Home stereo mini amp example

Example of a small & affordable amplifier that can be used to drive a lower impedance car subwoofer from your home stereo receiver. You can find these with a crossover built-in (as shown here) for under $30.

It’s a bit tricky in some cases – especially when using multiple car subwoofers and/or those like 2 ohm models, for example. A home stereo amp is a great answer to this problem and offers several benefits:

  • Can drive lower impedance subs directly
  • Low cost (often under $30) and very compact size
  • Some include a low pass crossover built in meaning you’ll save a lot of hassle

While I realize you might not want to have to spend money & wait for the stuff to arrive, it’s definitely worth thinking about. Here’s a good example of an inexpensive one I found.

How do you hook up a subwoofer to a receiver without sub output?

Image showing examples of line level RCA converters

Examples of line level converters use you can use to get an RCA low-level signal from a home stereo without subwoofer RCA outputs.

The good news that if you’re planning to use a small amp to power a sub at home but your receiver doesn’t have a subwoofer or other RCA outputs there’s a solution. You can use a line level converter, commonly used for factory-installed car stereos, to create some, then connect to a subwoofer amp.

You’ll want a good quality one with adjustable output level dials to be sure you don’t have problems with the signal level. They’re especially valuable to have as many vintage or older home stereos don’t have subwoofer outputs.

You can connect them just like you would a speaker, either to unused speaker outputs or also connect them alongside speakers already in use.

How many watts do you need for a subwoofer?

Man thinking about how much power for car subwoofer with home stereo

Car subwoofers are very inefficient speakers and are some of the most power-hungry you can find! The good news is that if you’re just looking forward to average listening levels you can get by with less power.

  • For easy listening, low-volume music levels, or sound from movies, you’d want at least 25 watts RMS of power per channel available to drive a subwoofer.
  • For a bit more “punch” that requires extra bass (especially the bass & thuds from DVD or BlueRay video sound) 50W+ would be much better.

If your home receiver is on the weaker side as some budget models are (for example, 15W-20W per channel) you’ll need a small external amp as I mentioned earlier. If you’re planning driving a car subwoofer with high volume and want some serious bass I’d recommend a minimum of 100W RMS and even more if you can afford it.

Bookshelf stereos usually can’t cut it – they’re just not designed to produce much power. However many decent quality home stereo receivers or home theater amps/decoders can do the job ok.

Home stereos vs car amplifiers

On the downside, home stereos don’t produce anywhere near the power of today’s car amps which typically have at least 75W to 100W or more per channel, if not several times that! On the plus side, when using a subwoofer inside your home you don’t have the terrible acoustical losses that you do in a car or truck.

This means when using a car subwoofer inside your home you need less power to hear it well.

Subwoofer sensitivity (efficiency) & volume

Some subwoofers produce more volume for the same amount of power. This is actually a standard specification used to compare speakers and the official name is speaker sensitivity. In other words, the sensitivity of a speaker describes the volume output it produces for a given amount of power, in decibels (dB).

A standard dB reading of 1 watt measured 1 meter (1M) away is used for this measurement in the speaker industry.

When comparing two subwoofers, for example, one might have a sensitivity of 87dB/W while a 2nd one has one of 91dB/W. This means the second produces more sound with less power. Because speakers require a doubling of power to increase another 3dB in volume, that means a more efficient speaker can use 1/2 the power or less than another speaker for the same volume!

That’s something to think about when comparing subs.

Will a sub work without an amp?

can you use a sub without an amplifier question man thinking

This one’s easy to answer, although it’s important to be clear about power & amplifiers. In general terms, no, a sub won’t work ok without an amp.

Hang on a second, though! What does “amp” mean in that case? To be more clear, here’s the long and short of it:

  • A subwoofer, like any other speaker, must be powered by an amplified audio signal with a decent amount of wattage in order to produce sound.
  • To properly drive a subwoofer for it to work well, that’s different; in that case, yes, without question you need an amplifier of sufficient power to drive it well.

That is to say, you can’t hook up a subwoofer to a non-amplified signal output from any stereo or other audio source. You need an amplified speaker output with a fair amount of power in order for it to work ok and sound right.

As I mentioned earlier, for casual listening inside your home you can likely get away with 25 watts for subwoofers with decent efficiency. However, if you want to drive a subwoofer hard and get that real bass “thump”, you’ll need a lot more power: 80-100W or more for a home amplifier.

More great articles about speakers and audio

Don’t miss out – there’s a lot more great reading ahead! Check out some of my other detailed articles:

Got questions or comments? Feel free to leave a comment below!

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

How to connect subwoofer to receiver without subwoofer output featured image

So your receiver doesn’t have a subwoofer output. You’re probably wondering what the heck you can do about it, and you might be worried if you’ll have to spend a lot of money for either a new receiver, subwoofer, or both!

I’ve got great news – 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. There’s no need to throw away your old receiver or break the bank!

Contents

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 which is boosted greatly using the built-in speaker amplifier, power supply, and 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 the bass enclosure which is directly wired to the speaker terminals or a passive bass crossover inside. These types are less common.

How a subwoofer produces bass

The subwoofer works by resting inside of an enclosure designed for it and to produce deep bass when playing music limited to low-end bass sounds.

In order to produce clean-sounding bass without vocals or other sounds a subwoofer can’t properly produce, a low-pass crossover is used to allow only bass frequencies to pass & be produced. 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 only bass for 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 adjustment
  • Subwoofer level adjustment know (the amplifier’s boost level)

The subwoofer input jack usually connects to a single mono (monaural, meaning both stereo channels are combined into one) output jack on the receiver.

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

Examples of 2 line level converters – both a 2 channel and 4 channel of each. 

How much do line level converters cost?

Line level converters range in price (for a good one) of about $15-$25 each. They’re connected to the speaker leads 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, will need a standard male-male RCA cable.

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3. 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.

These 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.

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. 

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. Connecting a receiver to a passive (non-powered) subwoofer

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 subwoofer crossovers and where to find them

Speaker crossovers such as this are sold both in a single (one speaker) or dual (2-speaker) model, 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 speaker load will react differently with the design.

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 separate “.1” bass channel as you 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, the bass channel can be very enjoyable.

Using a receiver without that output means you can’t get the same effect, but that’s only for surround sound mode. 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.

Just something to be aware of if you’ve ever considered upgrading later.

More helpful speaker info & diagrams

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