If you just want to get to wiring and don’t care about the technical stuff, click here to be brought to the subwoofer wiring diagrams page.

How to Wire Subs: Series and Parallel Wiring

Series

Series wiring for speakers means you are connecting the speakers like a chain. The positive terminal from one speaker connects to the negative terminal of the next speaker, then the positive of that speaker connects to the negative of the next speaker. You can do this with an infinite number of speakers. In this arrangement, if one part of the circuit is removed, nothing will work.

Series wiring will add the impedance of each speaker together, so for example: if you had three 2 Ohm speakers wired in series, the total impedance would be 6 Ohms. This will be explained in greater detail when I get to Ohm’s law.

For series wiring: Total Impedance = Sub Impedance x Total # of Subs

Parallel

Parallel wiring connects all of the positive terminals together and all of the negative terminals together. This means if part of the circuit goes out, all of the rest will still be connected, but the impedance will be affected.

Parallel wiring of speakers reduces the resistance seen by the amp, therefore making the amp work harder by pulling more current. Instead of adding all of the impedances together, the total impedance will be reduced further and further with each speaker added to the circuit. For example: if you wire (2) 4 Ohm subs together in parallel, you will get a total load of 2 Ohms.

For parallel wiring: Total Impedance = Sub Impedance / Total # of Subs, so if you have (4) 2 Ω SVC subs all wired in parallel, the total impedance will be 2 Ω / 4 subs = 0.5 Ω

Ohm’s Law 

Ohm’s law is the governing equation for all electrical circuits, and the equation is V = I x R where V=voltage, I=current, and R=resistance.

Voltage is constant for car audio (12V nominal, 14.4V with a running vehicle).

Resistance is constant (the total impedance your speakers are wired to).

Current will change depending on your impedance and the power your amp is capable of.

Rearrange the equation to read I = V / R.

This shows that if resistance is decreased, then the current the amp is pulling will increase. Therefore, the power output of the amplifier will increase because of the power equation P = V x I. Now you see why wiring subs to lower impedances will get more power out of your amp, and as a result and is why a lot of amps don’t like seeing too low of an Ohm load. A low ohm load will try to overpower the amp by pulling too much current.

This is a great Ohm’s Law chart to quickly see all the equations for power, current, voltage, and resistance:

Single vs. Dual Voice Coil 

The number of voice coils a subwoofer has determines your wiring options. Many people think DVC subs are more powerful than SVC or vice versa, but this is not the case. They make so many different versions of the same subs so you can get the total Ohm load you need no matter how many subs you plan on connecting together. A single DVC sub has two different wiring options right out of the box, whereas a SVC sub only has one.

Single Voice Coil (SVC)

Single voice coil subs are subwoofers that only have one voice coil. The impedance of a SVC sub will only be what that sub is rated at. For example, a single SVC 2 Ohm sub can only be wired to  2 Ohms.

Dual Voice Coil (DVC)

Dual voice coil subs have two voice coils. A single DVC sub can be wired to two different Ohm loads right out of the box by wiring it in either series or parallel. For example: a single 4 Ohm DVC sub can be wired to either 2 Ohms (parallel) or 8 Ohms (series). The Ohm rating on DVC subs is actually the rating per voice coil, so you cannot wire a 4 Ohm DVC sub to 4 Ohms.

How to Wire Subs to Desired Impedance

Now that you know what series wiring will raise total impedance and parallel will drop total impedance, I will show you how this is used in subwoofer wiring. Whenever you have (2) SVC subs of the same impedance, series wiring will always double that number, and parallel wiring will always half that number. Some math is needed for all other cases, especially when wiring multiple DVC subs together since you can have a mixture of series and parallel wiring in the same circuit.

For example: this circuit of two DVC 2 Ohm subs wired to a total load of 2 Ohms at the amp has the voice coils of each sub wired in series, but the two subs are then wired to each other in parallel. Wiring a DVC 2 Ohm sub in series gives you 4 Ohms. Then wiring two 4 Ohm subs in parallel will give you 2 Ohms. Hopefully that makes since.

Double check your final impedance with a multimeter after wiring before connecting your subs to the amp. I personally use this one from Amazon and it has worked great for me.

Below are some more diagrams for the most common wiring configurations. Post a comment or send an email if you don’t see the configuration you plan on wiring, and I can help you out. Here is a link to just the wiring diagrams for easier access: http://caraudioadvice.com/subwoofer-wiring-diagrams/

Subwoofer Wiring Diagrams – How to Wire Subs:

Single Voice Coil

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Two 2 Ω subs wired in series to 4 Ω

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Two 2 Ω subs wired in parallel to 1 Ω

Two 4 Ω subs wired in parallel to 2 Ω

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Dual Voice Coil

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One DVC 2 Ω sub wired in series to 4 Ω

Two DVC 2 Ω subs wired to 0.5 Ω

Two DVC 4 Ω subs wired to 1 Ω

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[one_half_last]

One DVC 2 Ω sub wired in parallel to 1 Ω

One DVC 4 Ω sub wired in parallel to 2 Ω

Two DVC 2 Ω subs wired to 2 Ω

Two DVC 4 Ω subs wired to 4 Ω

[/one_half_last]

I present the Pioneer AVH-4200NEX (discontinued)

This radio is Apply CarPlay and Android Auto compatible with AppRadio mode available for either phone. This radio will give you full phone support as well as provide you with navigation when your smartphone is connected. Don’t worry, though, it also works great if you have no intentions of using a smartphone with it.

It features 3 sets of 4V preouts as well as your typical backup camera compatibility and video in/out for DVD players or rear seat entertainment.

Sound quality wise it has a 13 band graphic equalizer, auto EQ and time alignment (with optional auto-EQ mic), 24 bit DAC, and FLAC support.

If you don’t want to have to use your phone for navigation, there is also a 6.2″ available with built in navigation for around the same price: the AVIC-5200NEX.

To see all the features of this great product, check it out on Pioneer’s website: http://www.pioneerelectronics.com/PUSA/Car/NEX/AVH-4200NEX

2017 Model Update

The AVH-4200NEX has been replaced with the AVH-4201NEX which is pretty much exactly the same, except for now it comes with a backup camera. For the same price!

If you live in Southeast Louisiana and would like any Pioneer products, feel free to email me at CAAInstallations@gmail.com or give me a call at (470) 635-1172.

There is also a new AVH-2300NEX which is similar but does not include backup camera and a couple inputs/outputs are missing, but it does include 3-way network mode now meaning you can fine tune your sound system by running fully active crossovers built into the head unit.

There are many different ways to get cheap lightweight sound in your car. Of course the easiest and lightest is just listening to music on your phone from its speaker or a set of earbuds, but phone speakers suck and earbuds aren’t safe while driving. So here I will cover a few different options you have to get some decent sound in your track car.

First thing’s first. Get rid of your radio and any other sound related stuff like any amplifiers, subwoofers, etc. This is still a race car.

Speakers

Coax speakers are going to be lighter than components in this case, so I would recommend sticking with those. If you don’t know the difference, check out my Basics to Upgrading Your System post.

Factory Speakers

One option for speakers, and often one of the lightest depending on your vehicle, is just keeping the stock speakers installed. Many factory speakers use tiny magnets and have plastic baskets and paper cones. Speakers made like this are usually the lightest but won’t sound too great. But who cares? It’s a race car!

Some factory speakers (cough cough Chevy) are terribly and barely handle radio power, so hooking an amp to them will probably blow them pretty quick. Get prepared to upgrade at some point if you go this route.

Upgraded Speakers

If you want better sound quality than stock speakers even though it’s a track car, find a decent set of coax speakers like these 6.5″ Polk db651 (check price on Amazon). They are some of the best sounding coaxial speakers I have heard for the price. Amazon has the weight listed as 5 pounds. I’m guessing this is shipping weight, so just the speakers should be even less. Or you can get the shallow mount version and save a few dollars and half a pound: Polk db651s slim mount (check price on Amazon).

Some of the lightest 6.5″ speakers I found were these Infinity Reference 6032si shallow mount 6.5″ coax speakers (check price on Amazon). Amazon has them listed at 1 pound. I’m guessing that’s not the total shipping weight like the Polks.

To save even more weight, go with a smaller speaker like a 5.25″.

Most of the weight of a speaker will come from the magnet, so the smaller the magnet, the lighter the speaker generally. But this usually means a less powerful speaker unless you find with a neodymium magnet like the Lanzar VX60S VX (check price on Amazon). Speakers aren’t going to add much weight, though. Maybe 5 pounds at the absolute most.  

Amplifier

This is where most of the weight savings will come in. I don’t recommend you use a big traditional style amplifier like the JL Audio JX360/2. Many companies are starting to make very small, lightweight amplifiers. Check out the mini amp section of Sonic Electronix. As you can see there are many different amps to fit any budget.

My Recommendations

Alpine Power Pack: There are many other amps similar to this one, but this is the only one I have experience with and have nothing but great things to say about it. Great size. Great sound. Great power output. It’s even bridgeable which means instead of using 2 of its single channels to get 45W, you can bridge it to 2 channels and get 90W per channel. It’s also very lightweight. Amazon has it listed at just 2.4 pounds. But that’s not it; this amp is very easy to unplug and take out of the car. So you could very easily just mount it with velcro or something similar, and when you get to the track disconnect it and take it out to save even more weight.

Make sure you get the Alpine KTP-445U model and NOT the Alpine KTP-445A as the “U” stands for Universal and the “A” stands for Alpine. The “A” model is meant to be plug-and-play to an Alpine head unit and won’t come with RCA inputs which is important as you will see later.

This amp has individual left and right channel gain settings as well as a selectable high pass filter.

Lepai LP-2020A+: This little amp isn’t necessarily made for car audio, but it will definitely work and is very light. I have one of these powering a set of speakers in my apartment and it’s a good little amp. Using it in a car, I would make sure it was mounted securely and you will be fine. It’s not quite as powerful as many of the other choices out there at only 20W per channel, but it was also only $20 on Amazon at the time of writing this (click here to check most recent price).

Just make sure to get the right center positive pigtail to wire it into a car like this one, or you might be able to get away with cutting of the AC power supply and using the other end as a pigtail to hook up power and ground.

2021 Update:
Now that bluetooth amps are so cheap and small, they are definitely worth a look for this purpose. This will use the bluetooth on your phone as the source, and all you need to do is hook the amp up like normal minus the RCA inputs and hide it away somewhere. This Herdio marine bluetooth amp also comes with an external controller, so you can keep your phone in pocket.

Connections

Now that you’ve picked out your speakers and amp, you will need to get it all hooked up. You can follow my How to Install and Tune an Amp – With Wiring Diagram post if you need help wiring up an amp.

If you chose one of these smaller amps that don’t draw much current, you can just hook up power and ground at the radio connections (though you may need to run a separate constant power wire to the battery if your amp draws more current than what the radio fuse is rated for your car). You can either cut the wires off the harness or use an aftermarket radio wiring harness to make it easier, and you won’t have to cut into the factory harness. To find what harness your car needs, go to metraonline.com and search for your vehicle. You will be looking for a female plug similar to this:

Now that you have the amp wired up, you are probably wondering what goes into the RCA input. Go buy a cable similar to one of these RCA to headphone jack Monster Audio Cables and plug it into the amp. Run the other end up to where you will put your phone or mp3 player.

Now you control everything with your music player and do away with a radio completely. This method of simple sound also works great in Jeeps or anything else where you don’t need a radio in your car.

An alternate method would be to buy a bluetooth adapter like this one. This might be a little advanced for a race car, but it will get rid of an extra wire that may be in your way otherwise. And this one uses regular RCA cables to connect to your amp.

Now you can do away with your radio and any other factory sound system you have and get way better and louder sound than what came in your car and still stay light enough for the track.

Update

My personal setup in my Miata is a Pioneer mechless single din head unit with bluetooth and the factory speakers. The mechless (no CD player) radio is lighter and has more features than the stock radio. The one I have is very similar to this newer MVH-X390BT (check price on Amazon) and it works great.

In my STi, I have an Alpine Power Pack with an auxiliary cable for the input with a volume control knob where the factory aux input jack was running the factory speakers. I will soon be upgrading the speakers to these Sony GS components (check price on Amazon) / (read my review on them here) and possibly adding some sort of bluetooth. Sony also has a version of a mini amp like this that I have had great success with, but it is not bridgeable like the Alpine (check price on Amazon).

Update (1/20/2019)

I no longer have the Alpine power pack in my STi. I did install the Sony GS components and love them. Check out my review (here) and installation videos of them (here). I also added a Zapco ST-4XSQ amp and Sony XAV-AX5000 head unit. I may do a review on this soon as it is by far my favorite radio out right now for the price, quality, and features offered. I am a Sony and Zapco dealer, so if you are near Baton Rouge, feel free to call or email me for pricing and availability.