How To Wire A 4 Channel Amp To 4 Speakers And A Sub: A Detailed Guide With Diagrams

4 channel amps are great and have a lot of flexibility for the most part. However, they’re intended for use with 4 speakers or 2 speakers and a sub – not both.

However, it is possible to wire a 4 channel amp to 4 speakers and a sub! I’ve put together some really detailed information to help make this as painless (and inexpensive) as possible.

Read on to find out how! There are plenty of detailed diagrams to guide you, too.

What you need to know first

Clip art image of a face thinking - Things to know content image

Let’s get a few things out of the way before we go any further. To drive 4 speakers and a sub with a single 4-channel amp you’ll have to make a few compromises.

I’ll explain here what I mean:

  • You’ll likely have to give up front-rear fader control ability as you’re giving up 2 channels for the rear speakers to drive a sub (2 front/2 rear).
  • Most but not all car amps today can handle speaker loads down to 2 ohms. If yours doesn’t, you’ll need a work-around I’ll show you. You may need a few extra parts.
  • Driving 4 speakers from 2 channels means the speakers are sharing the amp’s power, so you’ll have less power available to each of those.

That being said, don’t worry too much! You can still enjoy the music you love with a nice-sounding 4 speaker + subwoofer system.

What does the minimum impedance (Ohms) rating mean for an amp?

Image showing the minimum speaker Ohms rating for Rockville RXA-F1 4 channel amp as an example

Image showing a typical 4 channel amplifier’s minimum speaker load (Ohms) rating. Most car amps today have a minimum of 2 ohms per channel in standard (stereo) use and 4 ohms minimum when bridged. Never run an amplifier with a speaker load that’s lower than the rating! Your amp will run hot and possibly become damaged.

Today’s 4 channel (and other) car amplifiers have a minimum speaker load they can handle. The speaker impedance or “Ohms” rating of a speaker (also called the speaker load) is the resistance to the flow of electrical current that the amplifier sees at the speaker terminals.

Amplifiers are designed to handle a minimum speaker load. The rating shown on the amp or in the owner’s manual serves as a warning.

If you connect a speaker load below the amp’s minimum rating it can get hot and even become permanently damaged at some point.

I’ve seen this happen when people try to “get more power” by incorrectly wiring speakers to an amp. Don’t do it! Burning out your amp’s output stages is not a nice surprise.

Minimum speaker loads for wiring a 4 channel amp to 4 speakers and a subwoofer

Diagram showing series and parallel speaker Ohms calculation examples

Diagram showing how a car amplifier’s Ohm rating works with speakers. Speakers are usually connected in series or parallel (well, really, most often in parallel) which affects the total resistance an amp will see. That’s important because amps are designed for a certain minimum speaker load (Ohms rating).

As I mentioned above, most car amps today can handle a 2 ohm load per stereo channel (left & right channels) and 4 ohms minimum when bridged to drive an amplifier (called “mono”).

The real answer, however, is that it depends on your amp’s ratings. Always be sure to check to be sure. To keep it simple, I’ll summarize what will work for almost all systems & amplifiers you’ll come across.

The amp wiring systems I’ll cover here

In this post I’ll cover 3 types of systems as that should cover almost all amps you’ll find:

  1. 4 channel amps with a minimum speaker load of 2 ohms in stereo, 4 ohms bridged (for the subwoofer)
  2. 4 channel amps with a minimum speaker load of 2 ohms in either stereo or bridged
  3. 4 channel amps with a minimum speaker load of 4 ohms

#3 is less common but it’s one you’ll run across. Maybe you’ve got an older amp that’s been sitting around unused. If so, you’ll be glad to know there’s a work-around that I’ve come up with that will let you wire your 4 speakers up without damaging your amp.

4 Channel Amp Wiring Examples

Here are the speaker wiring and speaker (Ohms) loads possible for nearly all amps you’ll run across. I’ll describe 3 main system setups which I’ll cover in detail.

System 1: 2 speakers (parallel wiring) to each front channel = 2 Ohms x 2 + 1 subwoofer wired for 4 Ohms on the rear channels bridged for more power. This is the first and best choice for most modern 4 channel amps.

System 2: 2 speakers in parallel to each front channel = 2 Ohms x 2 + 1 subwoofer wired for 4 or 2 Ohms on the rear channels bridged for more power. 4 channel amps that handle 2 ohms bridged are less common but they are out there.

System 3: 2 speakers on each front channel (parallel wiring) wired with extra parts for 4 ohms per channel + 1 subwoofer wired for 4 ohms minimum. Because these kinds of amps can’t handle a 2 ohm load, it’s a bit harder and needs a different approach.

Testing speaker ohms with a multimeter

Image showing an example of how to test speaker ohms with a multimeter

Shown: An example of how to measure speaker impedance (Ohms) with a multimeter. It’s a great way to know for 100% sure what kind of speakers you’re dealing with to avoid problems with your 4 channel amp.

Car stereo and home speaker speakers are very similar except for the impedance rating they use. A speaker’s impedance value, measured in Ohms, is just the total measurement of electrical resistance the amp will see from the speaker’s voice coil.

Partly due to tradition in the electronics world and partly due to various other electrical reasons car stereos are commonly rated at 4 ohms and home stereo speakers around 8 ohms.

The good thing is that all you really need to know is roughly what the resistance of a speaker is. If you can measure that you can tell what Ohms rating to go by!

How to measure speaker Ohms with a multimeter

Example image showing how to use multimeter probes on a speaker

To measure the Ohms (resistance) of a speaker’s voice coil, hold the meter probes to the speaker terminals, making sure to keep firm contact to bare metal Paint, insulation, dirt, and solder flux can mess up your reading otherwise.

For example, we usually have a label on a speaker telling us if it’s 2 ohms, 4 ohms, and so forth. However, as crazy as it sounds, some speakers don’t!

That’s why it’s excellent to have a multimeter handy – you can find out 100% for sure.

Measuring speaker Ohms with a multimeter
  1. Set the multimeter to the Ohms setting. If the meter has an auto-ranging function you should be fine. Otherwise, set it to the lowest setting like the 10 Ohms or 200 Ohms range, etc.
  2. With the speaker disconnected, touch the speaker terminals with the meter probes. Be sure to touch bare metal on the terminals and make good contact.
  3. Read the measured value. The general range will tell you the Ohms rating of the speaker (Example: 3.6 ohms resistance would mean a 4 ohm speaker)

It’s important to be sure you’re not measuring across substances that can interfere with your measurement.

Things like the following can cause problems (I have seen this happen many times!):

  • Leftover solder flux or solder coating from manufacturing
  • Heavy oxidation
  • Heavy dirt, dusty, or other contaminants that build up over time
  • Paint or other coatings that don’t conduct electricity

If in doubt, you can rub them gently with a bit of sandpaper or even scratch the meter probes against the terminals to make better electrical contact.

Note: If a speaker is “blown” or burned out from abuse or physical damage to the voice coil you’ll never get a reading. That’s because for blown speakers the voice coil no longer has a complete electrical path you can measure.

Multimeters show an open circuit condition as “infinite” Ohms, which just means there’s no reading to be made.

Speakers don’t measure exactly 4 or 8 ohms!

Car and home speakers are rated by their general Ohms (impedance) rating. For example, 2, 4, and 8 ohm speakers are never measure exactly with those Ohm measurements.

That’s because each speaker’s design is a bit different from the next. The resistance you measure from a speaker is due to the voice coil’s resistance thanks to the long wire it’s made of.

Here’s an example chart to help you know what to expect when measuring speakers.

Speaker Rating Typical Measurements
2 Ohms 1-1.8 Ohms
4 Ohms 3.2-3.6 Ohms
8 Ohms 6 Ohms or more
16 Ohms 12 Ohms or more

As you can see, you won’t measure exactly 4 ohms for a 4 ohm speaker. It will be in the general range and close to its advertised rating, however.

What is “bridging” an amp? Why is this best for driving a subwoofer?

Diagram showing a 4 channel car amplifier bridged to 2 channels

Shown: Example of a 4-channel amp bridged to 2 channels.

Bridged mode (mono mode) is a built-in amplifier feature in which a “push-pull” set up is created: one channel (normally used for the left speaker) produces a signal that’s the opposite of the second channel (normally used for the right speaker).

When this happens the result is that you’ll get substantially more power with them working together than you would with one channel alone.

Bridged mode is a flexible way to get more power from 2 channels (in this case the rear channels, for example). That’s especially important because subwoofers are big, heavy speakers that need more power than small speakers to produce the bass sound you want.

DIAGRAM – How to wire a 4 channel amp to 4 speakers and a sub

Note: Most standard aftermarket car speakers are 4 ohms each so I’ll use that assumption for my diagram. Always be sure to check your speakers before you wire them to your amp to be sure they’re compatible.

(Or click on the image to enlarge & zoom)

Detailed diagram for how to wire a 4 channel amp to 4 speakers and a subwoofer

Using power resistors for harder installations (4 ohm min. amps)

Image showing examples of higher power resistors (4 ohms) for use with speakers

Shown: High power resistors that can be used with a 4 channel amp when adding more speakers. Using these will allow you to keep the total speaker load (speaker Ohms the amp sees) to a safe level so the amp won’t get damaged. They’re inexpensive and are easy to use.

Power resistors are larger versions of the resistors used in many electronic products. Unlike their smaller siblings, they’re designed to be able to handle a large amount of heat.

Because of this, they’re a great way to deal with more difficult speaker and amp systems. In example #3 I showed you earlier, it’s not possible to use two 4 ohm speakers in parallel with an amp that can’t handle 2 ohm loads.

We can use 1 large resistor for each speaker as a work-around for this.

This workaround won’t be necessary for most modern car amps. However, since a few amps out there can’t handle 2 ohm loads (especially older amps you might have that you’d like to use) I’ve included this just in case.

Diagram showing how to wire speakers with power resistors for 4 ohms total

In the case of a car amplifier that can’t go below 4 ohms per channel, there’s no other way. However, if we add one 4 ohm power resistor in series with each speaker we can use the math to our advantage.

By doing so, we’ll end up with two 8 ohms measurements in parallel which will give us a nice, safe 4 ohms per channel!

However, you’ll want to buy the right kind of resistor. I recommend at least 25 watt (25W) 4 ohm resistors. While you won’t find them in many local stores, the good news is that they’re affordable. I’ve used them many times for speaker problem-solving.

I’ve used some like these over at Amazon.

TIP: If mounting your amplifier is a challenge due to not have a good place to mount it, consider making a simple DIY amp rack

How to get around the lack of a front/rear fader

As I mentioned at the beginning, if you’re using a 4 channel amp to drive both 4 speakers and a subwoofer, you’re going to have to make compromises. There’s simply no way around it.

The biggest one that comes to mind is losing the front/rear fader control. However, I’ve come up with a sort of solution that helps a bit!

By adding inline resistors to the rear speakers you can drop their volume and it acts as a “fader” already. You can use an L-pad (speaker volume attenuation) site like this one to calculate resistor values for you.

I’ve already done the work for you, and here’s a great example. If you’re wiring 4 speakers and a subwoofer to a 4 channel amp, by adding 60 ohm resistors to the rear speakers you’ll drop the volume by 24dB (decibels).

The result will be that the sound is “faded” to the front and the rear speakers won’t be too loud.

Image showing to how to create a fader to rear speakers using resistors

Following the example I’ve provided in the diagram above it’s pretty easy. You’ll need to pick up some 15W-20W (or higher) resistors. I recommend about 60 Ohms as it will reduce the volume by 24dB.

That should be enough in most cases: Not totally silent in the rear, but most of the volume will be towards the front speakers.

What crossover settings should I use on my 4 channel amp?

Close up image of a car amp crossover controls

As most modern car amplifiers include very nice optional crossovers, for good sound it’s smart to take advantage of those.

Here are some good recommendations for the 4 main speakers and the subwoofer:

Speaker Crossover Settings
4 main speakers Flat (crossover off) or 56-60Hz high pass
Subwoofer 80Hz low pass

By using a high-pass filter for the 4 main speakers you can crank the volume when you want for more power & sound before distortion happens. When using a subwoofer, it’s really important to block vocals and upper-frequency music from getting to your sub.

The idea is to get “pure” bass sound as that’s what subwoofers are best suited for: Just purely producing great-sounding bass you’ll love.

What if my amp can’t be bridged?

Image with diagram of how to bridge an amplifier

While it’s true that nearly all amps with any “real” power today can be bridged from 2 channels to 1 channel (called “mono”, or bridging) for more power, some can’t. That’s especially the case for some older “old school” amps you might have in your closet but still like to use.

In that case, unfortunately, you’re really limited. Sorry! You have just a few options:

    1. Buy another small amp just for the subwoofer/subwoofers
  1. Run one small subwoofer from each of the rear channels

The problem with option #2 is that subwoofers need a lot more power to drive them well and sound good. There’s just no way around it.

8″ subwoofers are an option or a dual 4 ohm voice coil subwoofer could be used. That way you can safely drive each channel with a 4 ohm load even older amps can handle. These days, though, it’s usually easier just to get a cheap budget amp and avoid the headaches.

How to connect a 2 ch. car stereo to a 4 channel amp

Diagram showing a 2 channel car stereo connected to a 4 channel amp

If your stereo doesn’t have output channels that’s ok! You can still connect a head unit car stereo with only 2 channels (left and right) to a 4 channel amp easily. In most cases, you only need 2 RCA Y adapter cables. The head unit’s left channel RCA jack is connected to the left front and left rear amp inputs. Then the same for the right channels. If using speaker level inputs on the amp, use the connections shown above. NOTE!: Use only ONE of the two connections shown. Never connect both the speaker level and RCA jacks at the same time – speaker level signals can damage your head unit’s RCA outputs.

If you’re wanting to install a 4 channel amp for 4 speakers and a subwoofer but only have 2 stereo channels available, that’s ok.

As shown in my diagram, you can connect 2 channels to a 4 channel amp using either the speaker level inputs wired in parallel or by using RCA “Y” adapter cables.

RCA y adapter cable image

All you need is a decent quality pair (2 total) 1 female to 2 male RCA “Y” adapters No products found.

The sound quality will be exactly the same. Modern car amps are designed in a way such that all 4 inputs will get the same signal and there won’t be any problems.

After connecting the stereo to the amp, you’ll need to adjust the gain controls for both the 4 main speakers and the subwoofer output. My advice is to use a high-quality music track you know well already so you can easily tell when music sounds correct.

Additional suggestions & parts you may need

An amp wiring kit like this one will make your life easier! A a great (but affordable) amp wiring kit like this Belva 8-gauge complete kit includes not just the basics but a lot more. You’ll also need to pick up a 2nd pair of RCA cables (if using them) and maybe some extra speaker wire, too.

I can’t stress enough how important it is to be ready to install your 4 channel amp. While there are several ways you can go about it, wasting gas, time, and getting stressed out isn’t worth the headache.

It’s a lot better to start on the right foot and be ready at installation time. My advice is to pick up a good amp wiring kit and the tools you need beforehand.

About the author

Marty is an experienced electrical, electronics, and embedded firmware design engineer passionate about audio and DIY. He worked professionally as an MECP-certified mobile installer for years before moving into the engineering field. Read more »

Your comments are welcome.
  1. I have 2 DS18 x6m pro mid range loud speakers and 2 Timpano super tweeters both for rear of car I plan on getting the same for front currently some Pyle 3 ways are installed in front doors my radio is a 2 channel so purchased the y adapters also purchased a pioneer GmE360x4 4 channel amp what’s your recommended way to connect the speakers tweeters in their own channel and mods on another? Or rear tweeters and mids with parallel or series connection? I have filters for tweeters and the mids are rated at 8ohms figured this would give me the most options for wiring. The question is assuming I have the same set up for front which is my true intention I don’t mind leaving current front speakers to radio. Also should I leave x over at full and the kids have a high rating should i freq set in middle? Sorry for all the questions and information would help. FYI I will be adding a separate sup and mono amo for that sub in future

    • > what’s your recommended way to connect the speakers’ tweeters in their own channel and mods on another? Or rear tweeters and mids with parallel or series connection?

      It depends on the particular installation, setup, budget, amp channels, yadda yadda, but in this case, it sounds like you’re essentially wanting to set up your own 2-way component system with those tweeters & the mid woofers. In that case you’ll want to use 2-way speaker crossovers with the right crossover frequency and designed for that/those speaker impedances.

      That would be in parallel but the crossover will maintain the total speaker impedance of just once speaker as far as the amp or radio is concerned.

      > I have filters for tweeters and the mids are rated at 8ohms figured this would give me the most options for wiring.

      Unfortunately, if you picked 8Ω for the midrange, you’re going to have mismatched power levels. The midrange will receive 1/2 the power of a 4Ω speaker. One solution is to run a second speaker in parallel to get 4Ω, but that’s not usually practical to do.

      If you already have high-pass crossovers for the tweeters you can then get low-pass just for the mids and wire them all in parallel, basically creating your own 2-way system.

      > The question is assuming I have the same set up for front which is my true intention I don’t mind leaving current front speakers to radio.

      > Also should I leave x over at full You can if your head unit has crossovers built-in that you can use.
      > the kids have a high rating should i freq set in middle? <- I didn't understand this question. Basically, I believe you'd be better off powering front and rear from the 4 chanenl amp for the best power & quality. Don't drive anything with the head unit. Use a good 2-way setup in the front, with no higher than 4Ω speakers, and either coaxials or something affordable but good for the rear. The front speakers are the most important. The rear almost never sound very good because of how terrible the acoustics are in vehicle and it's not normally worth spending a lot on (good enough is usually fine). Best regards.

  2. Hi Marty-
    Can I use a pot or an L-pad variable resister to provide speaker fader control between front and rear speakers when using the setup detailed above that has the front and rear speakers tied in parallel?

    • Hello Bill. You can, with using a stereo L-pad being ideal. As most L-pads are 8Ω, when using it with 4Ω speakers you’ll need to add a 4Ω power resistor to each in series so the L-pad will work as expected.

      I’ve seen stereo L-pads here and there for sale so it shouldn’t be that hard to find one. Best regards!

  3. Hi sir, I have a Behringer ultra graph pro Fbq 1502 equalizer hooked up to a Amc 2/4 channel 2445 power amplifier and then my speaker system consists of a pair of Bose cube speakers, a pair of Bose 301 series V bookshelf speakers 8 ohms 10-100 watts and a Bose acoustimas 3 series II bass system.
    My question now Sir is that, how do I configure or wire my Amc 2445 power amp into a 3 channel mode to accomodate my Bose bass system ??
    Also my Behringer has a sub out Xlr output terminal, so where do I plug its other end ?

    Yours truly
    Mc Te

    • Hi, you don’t use a sub output with the Bose Acoustimass system and you don’t use a bridged output either. You’ll need to connect the Acoustimass system to a pair of stereo main channel outputs as shown in the owner’s manual for that system.

      The bass signal is derived from the stereo speaker inputs. Best regards.

  4. Wow!! Your knowledge is fascinating! I can understand only at my level but… formidable! I have a question however and there seems to be no answer online anywhere? I have an Infinity 70W pc amp (x 4) under the seat and 4 speakers. 2 are Infinity component (at rear, that’s my eccentricity) and 2 are what came with the car. There is a mid-bass and a tweeter but they say it isn’t a ‘component speaker’… ? The sound lacks enough bass, I need a bit more. So I bought a Blaupunkt Powered / Active Subwoofer and found to my dismay, that it is “2 channel”! So, if you would be so kind, my question is, can I have a setup with a 4 channel source, a 4 channel pretty powerful amp, 4 component speakers and a powered subwoofer? Thanks in advance for your reply 🙏🏽😊

    • Hello Apu. Yes, you can do that. You just need to run a stereo signal from the source, depending on your setup. For example, using “Y” adapters to run RCA inputs from the rear RCA to go to the powered subwoofer as well.

      Best regards.

  5. Dear Sir,

    I have (4) 4 Ohm speakers rated for 75-100W and (1) 4 Ohm subwoofer rated 50-175W. When I put two speakers per channel like your SYSTEM #1 diagram shows, do I divide the Watts per channel to figure out how much each is getting by two since two speakers are on each channel?

    Also, for the subwoofer, would I multiply the Watts per channel since there are two channels for the one subwooofer? Thank you for helping educate us.

    I am trying to fugure out the best sized amp to work with (4) 4 Ohm 75-100W speakers and one 50-175W subwoofer, thank you again.

    • Hello there. Yes you do exactly that, for whatever the rated power is at that give *total* speaker Ohms load. For example, for many amplifiers the power available at 2Ω is higher than 4Ω, assuming a lower impedance is supported.

      The power will be divided between them.

      > for the subwoofer, would I multiply the Watts per channel since there are two channels for the one subwooofer? Do you mean in bridged mode? Yes, it is typically 2x the power of a single channel although in some cases it can be slightly higher when used in bridged mode.

      If you have an amp with 75W/channel RMS that would be a good start. That would give ok power to the two speakers per channel and in bridged mode it’s decent power (about 150W) to drive the subwoofer. 100W/channel would be even better, but 75W can work ok.

      Best regards!

  6. Hey how is sound quality effected by wiring up the subwoofer to 2 of the 4 channels at 250w supplied power compared to using a mono 250w amplifier? Obviously the numbers are the same in terms of power supply but what about the general sound quality? Any difference?

    • Hi, if the audio signal(s) is/are the same, all things being equal, it should be the same. But using a mono amp guarantees the signal to the subwoofer(s) is combined into a single one. Whereas with a stereo amplifier that’s not always the case.

      When bridging two channels of a 2- or 4-channel amp however that’s taken care of.

  7. Good day, I must say that all the information that you give in terms of speaker, wiring, and ohms of resistance, are very enlightening for a lot of applications. I’m not going to get into a huge story or list of equipment which I have, but this question is more applicable to a home theater type receiver, rather than an automotive application. I am omitting the watt component of the discussion for simplicity. My home receiver’s channels have an ohm tolerance of 4 to 8 ohms. Which does allows for a little versatility.
    My main question, has to do with putting two speakers off of the same channel in parallel. This would be like your illustration of the 4 ohm amp channel with two 4 ohm speakers in parallel, each having it’s own 4 ohm resistor making each speaker 8 ohms…..but dividing by 2 to get back the 4 ohms the amp needs. Easy.
    But there is a form of illustration that I have never run a crossed which is a slight modification to described. This is essentially the same scenario but instead of the speakers being in parallel, and each speaker having its own resistor, the main wire coming off the amp has a single 4 ohm resistor, and then the speakers branch off into parallel, after the single resistor. So essentially, both speakers are sharing one resistor rather than each speaker having its own. I’m curious as to exactly what ohms resistance would be returned to the amp looking at it that way. There’s the possibility that a single resistor could produce instability in that system, which is why I’ve never seen it illustrated before. Or encountering, four ohms of resistance initially, and then taking the two 4 ohm speakers, and putting them in parallel, which of course would give you two ohms. Would that actually return six ohms back to the amp? I am just curious how the formulation for this would work out or if it’s even a recommended alternative to putting a resistor for each speaker. I suppose there’s also is a possibility that that initial four ohms of resistance would somehow be split between the two speakers, giving each speaker, six ohms of resistance, but because they’re in parallel, only returning three ohms to the amp, but that makes less sense to me. What are your thoughts? Thanks, Bill.

    • Hello Bill. Resistance divides when in parallel and adds in series. Therefore, if a resistor is connected in series with 2 speakers like you mentioned, the total will be R_resistor + (R_speakers_parallel). In the example you mentioned that is 4Ω + (4Ω || 4Ω) = 4Ω + 2Ω = 6Ω. It would not be possible to get 3 ohms that way as there’s a single resistor before the speakers.

      A single resistor in series with parallel speakers will certainly work, but isn’t ideal for several reasons:

      • It requires a resistor of at least 2x the power rating of a single one. These are often more expensive or harder to find.
      • It’s harder to work with in many cases since the other way allows adding the resistor at each speaker. A single resistor makes working with the speaker wire more difficult.

      While you can use resistors, a better option that avoids wasting power as heat can be found here where I explain speaker impedance adapters for using multiple speakers.

      Best regards.

      • Thank you for your information. Although I really didn’t think 3 ohms would actually be possible, I did consider that a more powerful resistor would have been needed in my single use resistor scenario. The volume control with an impedance adapter(VCIA) is an intriguing concept. I am wondering, because it’s part of a multi channel home theater system, is there such a device which would match impedance without messing with an individual volume control. I would still want to control the overall volume of the entire sound system, through the receiver itself. Or would it just be a matter of putting a setting on the individual (VCIA), and then I would still be able to use the receiver the way I would normally do to control all the speakers? (If this makes sense).
        I did look for some of devices that you mentioned, I have run across VCIAs with 100 watt and 300 watt capacities. If my receiver channels are 150 watt based, would the 100 watt VCIA be adequate, or would you go with the 300 watt one ?

        • > is there such a device which would match impedance without messing with an individual volume control

          Not really, as while there were some in the past, and there may be some out there, they’re very rare. You can use a standard volume control + impedance adapter and simply not change the volume. The volume portion is completely optional.

          > [..] I would still be able to use the receiver the way I would normally do to control all the speakers?

          Yes, it doesn’t change anything aside from adding multiple speakers and they will share the avaiable receiver power output. I would get a 300W rated one if you think you will be using over 150W of power from the receiver at some point.

          • Hello Marty, again,
            I took your advice and purchased one of the impedance matching devices as we discussed. It is a Monoprice 0VC 300, 300 W impedance matching outdoor volume control. The instructions for wiring, are pretty straightforward, and I’m not questioning that. But I did have questions because the material only seems to support the idea of using four ohm or eight ohm speaker pairs, rather than the six ohm speakers I wanted to pair up. I contacted product support to ask a question, and they told me it was not possible to do what I wanted, but I am skeptical of their information. As per our previous exchanges, you remember, my Ultimate goal, was to use 2, 6 ohm speakers in parallel and attach it to a receiver with 4 to 8 ohm capacity.

            [Edited, owner’s manual info text]

            Tech-support says that because the device is listed as working, either with eight ohm speaker pairs or four ohm speaker pairs, the fact that I want to use six ohm speaker pairs is something that won’t work. But as I study the tables, I realize that it may still be possible to do so. I will type out the tables for the lower 4 ohm speaker pairs, which I see as the lowest ohm speaker pair it can handle ( my 6 ohm pairs are a bit higher, but lower than the 8 ohm speaker pair tables. So……

            [Edited, see owner’s manual switch setting tables]

            Looking at all three tables, irregardless of amplifier capacity., It is possible to use just one pair of speakers. All the tables for one pair of four ohm speakers in parallel would yield 2 ohms of resistance.. The fact that I substitute a six ohm speaker pair would yield one more ohm of resistance which would be three. It seems like I should be able to use either switch position of 8X or 4X for my application. But tech-support seems confused that I was using six ohm speakers rather than fours or eights.

            If I have not supplied enough data, I can write out the other tables using the eight ohm speaker pairs rather than the fours that I listed. Do you have any thoughts on this or can you look up the instructions and then see if you think I can still use this device or if I have to go back to the resistor theory? Thanks again for your great information. Bill

          • Hi Bill. I edited your comment a bit to save space as I looked up the owner’s manual anyway before replying just to be 100% clear. I have to assume the support person doesn’t understand what it actually does.

            You can use the 4x setting as that will do what you need. In fact, if you like, with the 4x setting you could use up to 4 pairs of 6Ω speakers. You could also mix 6Ω & 8Ω, etc., on each channel if you want (it depends on their particular impedance as to how many you could use).

            Definitely I see what you mean about the manual – it wasn’t clear enough in my opinion. I hope this clears it up and best regards!

  8. Thanks Marty, you’re the best. Glad you got to see the manual. I agree, support did not really understand. And if I read the wiring correctly, there is a RT and LT input, as well as a LT and RT output, so it can be used in a left – right stereo config. Thanks again for all your help……you rock !

  9. My head unit has 4 pre amp outputs for the speakers. With the setup above should I be using the front LH and front RH speaker outputs or the rear outputs?

    • Hi, you can use the front RCA outputs for the main speakers and rear RCA outputs for the subwoofer(s). Technically it doesn’t matter unless the head unit has a subwoofer mode for the rear outputs.

      The speaker of course could be used to power speakers, but it will be mismatched versus the amp’s power and in many cases not as clear sound (depending on the particular system).

  10. Hi there,

    First of all, the information you have here is gold! Thanks for that! To be honest I am still learning and I am afraid I’ll fry my system if I do it myself. Just to ask, I am looking at using the following and was wondering if these components will work together?

    – Amplifier: KICKER CXA360.4 CLASS A/B 4CHANNEL
    – Subwoofer: KICKER TRTP82 8INCH 600WATTS/300WATTS RMS 2OHM
    – Component Speaker: KICKER IMPULSE 6.2

    Many Thanks!

    • Hi Raymond and I’m happy to hear you found it helpful. :)

      Unfortunately bridging an amp requires a 4Ω load, so the TRT82 isn’t a good match. If you get a 4Ω subwoofer (or dual voice coil 2Ω, wired in series for 4Ω) then you’ll be ok.

      Best regards!

  11. Hello,
    You are truly a perfect reference, and I have benefited greatly from your knowledge. I have a question, if you please. Is this applicable for powered subwoofer (subwoofer with built-in amplifier class D)? “TS-WX300TA”, Considering that I have:
    – 2 front Door sparkers (TS-A1687S)
    – 2 Rear Speakers (TS-A6977S)
    – Power subwoofer (the mentioned above)
    – 4 X 70 amplifier (GM-E7004)
    – OEM head unit (Nissan)

    • Hello Amit. Yes, you can use those together as the powered subwoofer is separate from the 4 channel amplifier.

      It’s probably best to use a 4 channel speaker level to line level converter to go to the 4 channel amp then RCA “Y” cables to also go to the subwoofer’s signal inputs. Best regards.

  12. Marty I have a stereo on a boat .The stock wiring has the speakers inside the boat wired directly to the radio speaker wiring harness and has 6 speakers. The radio also has rca cables going to a 5 channel amp feeding 4 speakers and a sub to the cockpit (outside part of boat) . Is this type of wiring O.K. or is it totally wrong? Thanks

    • Hi Chuck the current wiring is *probably* ok, but not optimal. Generally it’s better to power all the speakers from the amp/amps. So the remaining two speakers would be best off powered by the amp, assuming it can handle two speakers wired in parallel per channel.

      Assuming they’re 4Ω speakers, then the amp would need to be rated for min. 2Ω per channel but most are these days. If some speakers are powered by the head unit, once you start cranking the volume up they’ll be mismatched versus those powered by the amp due to the power difference.

      Best regards!

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