How Many Speakers Can You Use With A 4 Channel Amp?

Welcome! In this article, I’ll help you connect multiple speakers to 4 channel amps, whether for home audio, car audio, or general speaker system use.

I’ve created some helpful diagrams as well to help you.

How many speakers can you connect to a 4 channel amp?

how many speakers can you connect 4 channel amp

The number of speakers you can use with a 4 channel amp depends on several things, but the short answers are:

Parallel speaker connections:

  • You can connect eight 4 ohm speakers (two per channel) to an amp rated at 2 ohms per channel.
  • You can connect eight 8 ohm speakers (two per channel) to an amp rated at 4 ohms per channel.

Series-parallel speaker connections:

  • You can connect sixteen 8 ohm speakers (four per channel) to an amp stable to 8 ohms per amp channel.
  • You can connect sixteen 4 ohm speakers (four per channel) to an amp stable to 4 ohms per amp channel.
  • You can connect thirty two 4 ohm speakers (eight per channel) to an amp stable to 2 ohms per channel.

However, it comes with a price. That’s the case because each speaker will get a portion of the amp’s power output at the total Ohms load you use. This means that you must remember that the speakers will share the available power whenever more than one speaker is connected.

This will also affect the maximum volume possible for each speaker since less power will be available. The more amplifier channels available, the better, for this reason.

NOTE: You may have noticed the number of speakers per channel I’ve listed above even (2, 4, 8, etc.). That’s because the total Ohms will work out to the best compromise in that case. Odd numbers of speakers can be used, but one or more speakers will receive an uneven amount of power versus the others, so I won’t cover those cases here.

Why it’s better to connect some speakers in parallel and not in series

parallel vs series speaker wiring sound quality problems diagram

Unlike single cone speakers,  2-way or coaxial speakers use a speaker crossover to filter sound directed to the tweeter and/or woofer. A speaker crossover’s cutoff frequency (crossover frequency) depends directly on the speaker Ohms it is connected to. 

When multiple speakers with an inline crossover (such as car tweeters or 2-way home stereo speakers) are connected in series this can affect the sound.

That’s because crossover components (capacitors and inductors) expect a specific speaker Ohm load based on their design. When more speakers are added in series, this increases the speaker impedance (the speaker’s resistance to current flow, in Ohms) they see. This causes the crossover frequency to shift, allowing unintended sound frequencies to pass. 

Connecting crossover components in series (inductors and capacitors) causes them to interact with each other which can cause issues. Lots of things in the music you hear like bass and treble or the range of sound they produce can be negatively affected.

It’s something to bear in mind when you want to connect multiple speakers. Technically speaking, it will work and provide sound, but it’s not what you’ll want for the best sound possible. It’s not a problem with multiple subwoofers, however, aside from making sure they have enough power.

Remember these general rules for connecting speakers:

  1. Whenever possible, connect 2-way, 3-way, or other speakers with a crossover in parallel for the correct sound and performance. This may mean you’ll need a speaker impedance adapter in some cases (see below).
  2. Single cone speakers (those without a separate tweeter, or a crossover, for example) can be connected in series without affecting the sound.
  3. When the amplifier can handle the Ohms load, connecting speakers in parallel offers the best power to each speaker.

What does a speaker impedance adapter do?

diagram of how a speaker impedance adapter can be used

A speaker impedance adapter allows you to safely wire speakers, connected to its output side, in parallel for best sound quality and power to each. The amplifier, stereo, or AV receiver will “see” the correct and safe total speaker Ohms load on the speaker terminal side thanks to small electromagnetic transformers used in them and configured for your speaker system.

The transformers use a step-up or step-down voltage scaling property, much like a power adapter in your home, to change the output applied to the speakers. The end solution provided is that rather than having two speakers in parallel lower the speaker Ohms to a level that could damage the speaker’s output electronics, it will instead present the expected Ohms load.

Depending on the model and options, some provide additional flexibility such as using 4 ohm, 6 ohm, or even 2 ohm speakers with an 8 ohm amp and vice versa. They’re also convenient when using an additional speaker pair in your backyard or pool via a speaker selector switch.

In fact, even though they’re sold for home stereo use, many will work fine with a car head unit or amplifier in your vehicle as well!

DIAGRAMS: Example 4 channel amplifier speaker connections

The example speaker wiring diagrams are separated into two groups: Amps rated for a minimum of 8 ohms per channel (home stereo amps, typically) and those for 4 ohms or 2 ohms per channel (car or marine amplifiers, typically).

Choose a diagram based on the minimum Ohms per channel your amplifier is rated for. This should be listed in the specifications and at the speaker terminals in many cases.

Diagram #1. 8Ω / 4 channel amplifier speaker connections

connect multiple speakers to 8 ohm 4 channel amp diagram

Diagram #2. 4Ω / 4 channel amplifier speaker connections

connect multiple speakers to 4 ohm 4 channel amp diagram

Can you use 6 speakers with a 4 channel amp?

Yes, in many cases you can power 6 speakers with a 4 channel amp directly. In other cases you can use a speaker impedance adapter to connect additional speakers that otherwise would not work well.

The connection and wiring setup you can use depends on several things:

  • The amplifier, stereo receiver, or home theater receiver’s minimum Ohms rating per channel.
  • The speaker impedance
  • The type of speakers (example: single cone speakers or 2-way and 3-way speakers with a tweeter and woofer)

EXAMPLE DIAGRAM – How to connect six speakers to a 4 channel amp

connecting 6 speakers to 4 channel amp diagram

In the diagram above, I’ve provided several example setups which are safe to use via the rear speaker outputs of an amp. The additional pairs can be wired in parallel in some cases directly but not in all (hence the need for speaker Ohms impedance adapters in some cases).

Note that in cases where wiring two speakers in parallel would still be supported by the amp’s minimum Ohms rating, single cone speakers would work fine without sound issues due to crossovers. In that case an impedance adapter is not required or recommended.

Marty

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. Hi,
    I like how good information is provided on this website, very helpful. The only thing is, I don’t understand what amp I would need for my setup. Because they are all rated in Watts, rather than Ohms.
    E.G. I have an LG soundbar which has a rubbish logic board, its BT does not reconnect back to the device when off\On the soundbar. I want to replace the BT amp inside it or take out the speakers and build a new BT speaker. It is rated as 100W, and it has 4 speakers @ 8 Ohms (I think) and 2x tweeters @ 4 Ohms.
    Do I need to look for an Amp 4×50W? Then it would be 2ch for tweeters and 2ch for the remaining 4 speakers?

    Reply
    • Hi there. You should be able to use a 2 channel, 4Ω min. rated amp to do this. The tweeter likely has a crossover in the form of a capacitor which also will allow using 2 speakers per channel.

      There are lots of mini class D amps with integrated Bluetooth out there as they’re popular for projects including ones like this. I’ve seen them for sale many places like Parts Express, AliExpress, eBay, Amazon, and more. Best regards!

      Reply
  2. I wondered if I can get some of your advice and stereo expertise on my 2013 FLRTX setup. I have 8 speakers connected (2 on each channel) at the moment but I just added two 8” HMX 8 marine speakers to my bags. My plan was to connect my Hertz ST25 tweeters directly to my Pioneer NEX3500 head unit to free up some power in the amp and then connect the HMX 8’s straight to the amp with the MPX690.3 Pro’s. My question is what would the best way to connect all of my speakers so that I get the most complete sound of highs mid and lows but also get some solid bass out of my HMX 8’s and MPX690.3 Pro’s. I was told That I could possibly bridge the HMX 8’s and MPX690.3 Pro’s together to get more bass or a few other possible setups but I am unsure. Please help!

    Thank you in advance for your time!

    Head unit, Amp and Speaker info below:
    [EDITED FOR LENGTH]
    – Pioneer AVH-3500NEX
    – HXM800.4D – HXM 4-Channel Full Range Class D Amplifier (in fairing)
    – Font Fairing(1 in each side): MPX 165.3 PRO Coaxials
    – Lower Fairing(1 in each side): MPX 165.3 PRO Coaxials
    – LIDS (1 in each lid): Hertz MPX690.3 Pro 6″ x 9″ 130 Watts RMS 3-Way Coaxial Speakers
    – BAGS (1 in each bag): MX 8 hi-performance marine coaxial
    – Font Fairing(1 in each side): ST 25

    Reply
    • Hi, you can connect the tweeters to the head unit but it will be mismatched versus the amplifier due to its much lower power output. If you’d like to use 10 speakers you’ll either need to add a 2nd amp or switch to a 6 channel (minimum) amp to be able to provide enough power along with supporting the additional Ohms load (since it can’t support 3 pairs of speakers in paralle – that’s below the 2Ω min. rating).

      The issue with getting bass with standard coaxial speakers is 1) coaxial speakers aren’t generally good for bass response, and 2) the enclosure they’re in will make or break the lower frequency response they can produce.

      Really, if you want to use coaxial speakers there’s not much you can do aside from using them the way you are currently doing it, but perhaps using the amp’s high-pass crossover for the smaller speakers around say 50-60Hz to prevent distortion. You can then try and see what you get from the HMX speakers.

      For the best volume, sound quality, & lowest distortion, 2-way component speakers with separate tweeter & woofers along with a 2-way crossover would be ideal. You could then try using woofer capable of producing bass to fill in the bottom end. Best regards!

      Reply
  3. Zdravim mam dotaz…potreboval bych zkloubit s totim zesilovacem [-] Tyto reproduktory [-]. [-] ktere mam na totech vyhybkach [-] A jeste s dvemi subwoofery [-] [-] Jeto realne??dekuji za odpoved

    Reply
    • Dobrý den, Davide. (odkazy upraveny)

      – Věřím, že výhybky jsou pravděpodobně 4Ω a neznám impedanci reproduktorů Vector. Pokud jsou reproduktory 8Ω (nebo nejsou paralelní pro celkem 4Ω), nevěřím, že by to fungovalo.
      – Zesilovač umí napájet reproduktory, ale pro subwoofer woofer by bylo ideální zapojit zadní výstupy v “přemostěném režimu”, který by byl dimenzován na zátěž 4Ω.

      Pokud máte konkrétní dotazy/atd. a chcete sdílet odkazy na produkty, bylo by lepší mě kontaktovat prostřednictvím mé kontaktní stránky.

      S pozdravem.
      ———————
      Hello, David. (links edited)

      – I believe the crossovers are probably 4Ω, and I do not know the impedance of the Vector speakers. If the speaker drivers are 8Ω (or do not parallel for 4Ω total) I do not believe this would work.
      – The amplifier can power the speakers, but for a subwoofer woofer it would be ideal to wire the rear outputs in “bridged mode”, which would be rated for a 4Ω load.

      If you have specific questions/etc. and want to share product links it would be better to contact me via my Contact page.

      Best regards to you.

      Reply
  4. Tengo un aplificador Yamaha RXV 673 no pedo encenderlo no está en potecion enciende y se vuelve a apagar y enciende lalus roja en están by yalo e reiniciado y an ae lo mismo alguien que peda ayudar con algún comentario que me sea de utilidad lo agradezco

    Reply
    • Hola Luis. Me pienso tienes un problemo adentro con tu amplificador. Podria ser un posible problema con la fuente de alimentacion o algo que haga que se proteja apagandose.

      Sin embargo, la unica forma de averiguarlo es solucionando el problema y diagnosticandolo. Saludos y que tengas un buen dia.

      Reply
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