Power Wire Calculator

Don't cheap out on your power wire!*

0 Gauge Wire going into a JP23 Amplifier.

You need a big thick power cable (with a fuse near the battery) to get DC power from your battery to your amplifier.   But wire, especially high-quality copper wire, can be very expensive, like these:

Kicker Dual Amp Kit

KnuKonceptz Dual Amp Kit

4 Gauge Power Wire for a JL Audio Amplifier

To help you figure out what you need, without wasting your hard earned cash, just plug some info into this calculator and you will be all set!  The calculator is designed to let you pick the wire size and it will tell you how much voltage drop you will get due to the resistance of the power wire.  That voltage drop will either be green (good to go) or red (you need a bigger power wire).  The calculator will also make sure that your wire is large enough to supply the required current, details on this below.  

A few things first:

1. There are two types of wire Oxygen Free Copper and Copper Clad Aluminum (CCA).  CCA is cheaper, but has 50% more internal resistance and is significantly more prone to corrosion.  Thus CCA is never recommended.  But, you can spend your money any way you like.  So both are included in the calculator.
2. Some amplifier manufacturers lie about their power ratings or list bogus "peak" or "max" ratings.  Use only RMS wattage.  Watch a few amp dyno videos to figure out which brands lie about power ratings and which brands provide reliable numbers.  If you are running multiple amplifiers then input your total system power in watts RMS.  
3. Cars run on 12v DC, but they don't.  Your voltage in your car, assuming it has not been modified, will be between 12 with the engine off and 14.4 with the engine running.  13.8 is a good middle ground, but you can input a wide range into the voltage field.  Be realistic.  
4. Amplifier efficiency varies widely.  Class AB amps are less efficient than class D.  I usually assume 60% for class AB and and 80% for class D.  If you are running cheap amplifiers pick a lower number, quality amplifiers (like this one) will be much more efficient.  But no amp is 100% efficient. 
5. For the wire length this is your main power wire that runs from your battery to your amplifier. If you have multiple amplifiers then you will need a fused distribution block when you split your wire down into smaller wires for individual amplifiers.  For this calculator just assume that you are running a power wire directly from the battery to the amplifier.  
6. Choose your wire size, the ones listed are the ones commonly available from car audio retailers. 
7. Hit calculate and you will get your result.  Green means go and red means you need a bigger wire. 

Car Stereo Power Wire Calculator

Wire Type:
Oxygen Free Copper (OFC) Copper Clad Aluminum (CCA)

Amplifier RMS Power (Watts):

System Voltage (Volts):

Amplifier Efficiency (%): (Enter 50-90)

Wire Length (Feet):

Wire Size:
0000 AWG 00 AWG 0 AWG 4 AWG 8 AWG

Results:

Enter all values and click "Calculate" to see the results.

Not all amplifier kits are made the same, some do not include RCA wires and distribution blocks. If you need those here are some recommendation's.

• RCA Wires: Option 1
• RCA Wires: Option 2
• Distribution Blocks: Option 1
• Distribution Blocks: Option 2
• Distribution Blocks: Option 3
• Distribution Blocks: Option 4

To learn more about power wire check out this helpful video

What us up with the current draw calculation?

The current draw calculation is based on a concept called "circular mills."  A "mill" is one thousandth of an inch.  A circular mill is the area of a circle that has a one mill diameter.  The rule of thumb is 300 circular mills per ampere of current.  Thus if you need to deliver 100 amperes of current you need at least 30,000 circular mills.  Since CCA has 50% more resistance compared to copper we use a threshold of 450 circular mills per ampere for CCA wire.  This calculation does not matter most of the time.  But in situations where you have very short runs (like the pic at the top of this page) an 8 gauge wire will not loose more than half a volt, but the wire is still to small, not enough circular mills per amp.  

*FCC Disclaimer: This post contains affiliate links and the owner of the website may earn a small commision if make a purchase after clickign on a link. This does not cost you at thing.

Series-Parallel Calculator

What is a dual voice coil subwoofer and how do you wire it?*

All you really need to know is that a dual voice coil has two sets of terminals, this gives you added flexibility when connecting a subwoofer to an amplifier. Speaker resistance is much more complex, more on that below.  But for now the goal is to match the nominal impedance of your subwoofer (or subwoofers) to your amplifier.  Here is a schematic to show the difference between single and dual voice coil subwoofers.

Here is a picture of a pair of dual voice coil subwoofers, the terminal pairs are circled in red.  There are two pairs on each subwoofer.  In this case the voice coils are wired in series.  For more on this scroll to the bottom of the page for some sample wire diagrams.

Here are some schematics showing the two ways that you can wire up a dual voice coil subwoofer.

  

 

Here is an example of a single voice coil subwoofer.  It has just one set of terminals.

Here are some schematics demonstrating series vs parallel for a single voice coil subwoofer.

Subwoofer Ohms (Series-Parallel) Calculator

With the above information you should know enough to use this calculator, additional wire diagrams are included below.  One caveat, this calculator will not let you mix impedances or numbers of voice coils.  It assumes that you are working with matching subwoofers.

Subwoofer Resistance Calculator

Select Voice Coil Resistance (Ohms): 0.5 Ohm 1 Ohm 1.5 Ohm 2 Ohms 4 Ohms 8 Ohms  

Select Number of Voice Coils: 1 Voice Coil 2 Voice Coils 4 Voice Coils  

Select Coil Configuration: Series Parallel  

Number of Subwoofers:  

Select Subwoofer Configuration: Series Parallel

Now I am going to break your brain!

In this picture I am measuring a 4 Ohm voice coil and it is not 4 ohms!  

That is because subwoofer impedance is actually a lot more complex.  I explain some of that in this video:

As you can imagine there is a near infinite number of possible wire configurations.  Here are some examples to help you get started wiring up your own system.

Here is a video expanding on your wire options:

*This post contains affiliate links, if you make a purchase after clicking on a link the website owner may earn a small commission at no cost to you.

 Discount Codes for DIY Audio Fans!

Savard Speaker Systems: DIYAUDIO, 7 % off

Custom Speaker Pods: DIYAG, 10% off

Battery Hookup: DIYAUDIO, 5% off

Parts Express: DIY5, 5%

Jag35: DIYAUDIO, 10%

If you are tired of audio companies that LIE about their power ratings click here.

 

maxx-power-audio

The BEST wood for subwoofer boxes?

This post is going to hit a nerve!  People get very sensitive about this subject.

Plywood (left) and MDF (right) Subwoofer Enclosures

There are two main materials that we build boxes with.  Plywood and MDF so here are the pros and cons of both.

Five Pro's of MDF:

1. MDF is heavy!  You want heavy and dense for your sub box!  
2. MDF is "inert" -- meaning it will not resonate and color the sound.  It also does not expand and contract as humidity changes.  
3. MDF is true to size!  3/4" MDF is 3/4"  While plywood is often NOT
4. MDF is easy to Machine.  If you are dong complex router work use MDF, it will not tear out like Plywood.
5. MDF is CHEAP!  That is not reason to use MDF, it is a great material for the above reasons.  So think of the lower price as a bonus.

Carpeted MDF Enclosure

Five Pro's of Plywood:

1. Plywood is light, up to 50% lighter than MDF.  
2. Plywood looks awesome!  If you know how to finish and stain wood then you can make some amazing works of art out of plywood.  
3. Plywood is inert -- just like MDF the box will not color the sound.  Especially if you use a high-quality plywood.  
4. Plywood plays well with wood screws.  It is less prone to splitting and the layers do a good job of holding on to screws. 
5. Finally plywood is strong!  How strong, check out this video!

Five Con's of MDF:

1. MDF is HEAVY!  Yes, I listed that as a pro.  But heavy boxes break backs!  Plus they add weight to your car.  
2. MDF does not like screws.  It splits if you don't drill a piolet hole and you need coarse-grain screws or they will pullout.   
3. MDF is hard to paint.  This goes against conventional wisdom, but it is true.  Especially the edges.  You need to seal it before you paint it.   But the best thing to do is cover it with carpet or veneer.  
4. MDF generates nasty dust.  Fine particles that get everywhere, like your lungs.  You do need a dust mask when you do this kind of work.  
5. MDF can't get wet!  It will swell!  Also, don't feed it after midnight.  

Plywood Subwoofer Box

Five Con's of Plywood:

1. Plywood is expensive, at last the good stuff is.
2. You are not using good plywood.  I see a lot of boxes online that use construction grade plywood and even if you opt for "birch" or other hardwood plywood from the local home center these are not hardwood.   These have a decorative hardwood veneer, the plys are all pine.  
3. The plys  are visible, and they can be ugly.
4. Plywood is undersized -- it is typically 23/32" of an inch.  So you need to take that variance into account when building your box.  
5. It is hard to make it look good -- you need some experience with stain or the box will look nasty.

To learn more check out this video:  

Woodworking Tools for the DIY Subwoofer Builder!

 Here is a short list of must-have woodworking tools you will need for your DIY subwoofer!

Subwoofer Box for 2 12" Drivers

Router:

Bosch 1817 Kit

I have been using this Bosh brand router for years.  Go ahead and get the kit with both the plunge and fixed base.  

Circle Jig:

Jasper Circle Jig.

This is the legendary, and reliable Jasper Circle Jig.  It is a must-have, and the best tool for DIY speaker cut outs.  For those that don't like making Jeff Bezos even richer, consider purchasing one from Taylor Tool Works. 

Spiral Router Bit:

Spiral Cut Bit

Go ahead and spend the money on a quality bit.  You will use this, along with the circle jig and plunge router, to plunge into wood and cut holes for speakers, ports, and terminal cups.  A straight bit will work, but these spiral bits plunge much better.  Again, check check out Taylor Tool Works as an alternative to Amazon.  

Cord Reel:

Cord Reel

I regret not getting one of these sooner!  Hang this to your ceiling or high up on a wall so you are not constantly fighting with extension cords.  

Circular Saw:

Circular Saw

Even though I have a great table saw I still use my circular saw quite often.  You can break down plywood and MDF to manageable sizes to use on the table saw, or just use your saw with a straight edge or edge guide.  Go ahead and get a cordless one.  The brand does not matter, get one that uses the same battery as your cordless drill.

Kreg Rip Cut:

Kreg Rip Cut

This may be my favorite beginner/DIY tool.  With a little practice you can get straight, accurate, and repeatable cuts.  Plus this thing is CHEAP.  Check out my video review:

Brad Nailer:

Brad Nailer

Some people prefer "glue and screw."  I prefer to use a brad nailer.  I use Ryobi simply because they were the only cordless platform with an affordable cordless nailer.   You can use a pneumatic one, but you will also need an air compressor, plus hosses and accessories.  

Hearing Protection:

3M Worktunes

Yes you DO need hearing protection.  I have been using 33M Worktunes.  These let you listen to music while you work, plus they are bluetooth so you can take phone calls.  

Dust Mask:

Dust Mask

You will be tempted to skip the PPE.  DON'T!  Get a dust mask!  Even the simple white ones are better than nothing.  

Eye Protection:

Eye Protection

Yes, you need to use these.  I went ahead and got some prescription safety glasses.  The last time I had an eye exam.

Bass on a Budget

All builds are budget builds, budgets are just different.  Here are four budgets and some gear that will get you the bass you crave.  Make sure you check out the end of the article for a few caveats*.

 

$300 Amazon Build

For this build we are going with a single 12" instead of an 8" or 10".  Cone area is king.   

1. Enclosure:  SKAR Audio SK1X12V     $94
   
2. Sub:  SKAR Audio SDR-12 D2             $90
3. Amp:  LEGIS Audio 500.1 D                 $66
4. Wire: Recoil OFC 8 Gauge Kit               $50
   

LEGIS Audio 500.1 D

 

That puts us right at $300 before taxes, most of it is on amazon, so shipping is free for prime members. I have personally reviewed the SKAR box and the LEGIS amp.  If you go this route pay close attention to the subwoofer and the amp.  Make sure you get the dual 2 ohm sub.  Wire the two connections in parallel to get the most power out of the amp.  When looking at the amp LEGIS also has a "1600 watt" version for the same price.  Look at the fuses.  The 500.1 D has 2 25amp fuses.  The "1600 watt" version has 1 25 amp fuse.  You cannot pull 500 watts through a 25 amp fuse, much less 1600.  You will be hard pressed to do beat this set up for under $300.  SKAR has the budget bass market cornered, and Recoil is putting out some great budget gear. The weakest link in this setup is the amp.  You may want to spend some more and upgrade to the Recoil RED 600.1 for another $30.  But that puts you over the budget.  You may be tempted to go with a cheaper sub box.  Please don't.  Here is an image of the SKAR box nest to a cheap enclosure.  

SKAR Audio SK1X12V

 

 

The SKAR is bigger, a bigger box will give you more bass. It is called Hofmann's Iron Law:

 

$500 NVX Build

Have you heard of Sonic Electronix?  If not you should check them out.  Their house brand,NVX, provides excellent bang for the buck.  For the $500 build we are going to kick things up to a pair of 12's  and 700 Watts total system power.  If you purchase directly from NVX use the COUPON CODE DIYAUDIO10 for a discount!

1. Enclosure: NVX XMDFP122  $120
2. Subs:  NVX NSW 124 v2     $90
3. Amp:NVX XAD 11   $110
4. Wire: NVX 4 AWG Kit:  $90

That brings us to  $410. If you use the discount code it brings you down to $370. Plenty of room to throw in some NVX Sound Deadener to keep your trunk from rattling or a quality bass enhancer to integrate with your factory radio..  The subwoofers are dual 4 ohm, when you wire everything up in parallel you will get a 1 ohm load.  Double check when ordering to make sure you have the dual 4-ohm subs in your cart.  The amp is a "Brazilian style" full-bridge.  Some people do not like Brazilian style amps.  One alternative is this N-Series amp.  Another alternative is the Recoil RED 600.1:

 

 $1000 Build

At this level we kick things up to a pair of 12's and bigger amp.  This is the threshold for what you can do with a stock electrical system. You may need to consider upgrading your battery or alternator (or both) before ordering this gear, but it is not 100% necessary.  All of this is available from Down4Sound.
 

1. Enclosure, Subs, and Amp:  Down 4 Sound Bass Package:  $900
2. Wire:  Down 4 Sound 4 Gauge OFC kit $70
   

JP8 AMP from Down4Sound

 

This is a package deal.  I personally run the single 12 version of this with the same amp and I am very happy with the performance.  The official ratting on this amp is 700 watts, but this amp will give you over 1200 watts IF you have a good enough electrical system.  Expect 900 watts at the most with stock electrical.  I tested it on my bench and was able to get 900 watts before my power supply was unable to keep up.  But I still got over 800 just running off of the battery.  Plus the JP amps have the best bass knobs in the business. 

 

 Before we look at the next budget, we need to draw a line right here.  At this point we move from "daily driver" systems that can work OK on stock electrical to a system that requires upgraded electrical.  Most people will install a second battery, but that is the wrong thing to do.  Most people do that because it is cheaper than doing it the right way.  What is the right way?  Upgrade the alternator.  You might end up spending $300 to $600 on this, you will probably need a new serpentine belt.  You will also need to look very close at your available space.  The boxes get huge, so you will need to make sure your subs will fit.

 

Down 4 Sound Pro-Fab Enclosure

$2,000 Build

Now we are really kicking things up!  We are moving to some big beefy 15" subwoofers in a HUGE enclosure.  

1. Enclsoure:  2 x 15 Profab Enclosure  $550
   
2. Subs:  Sundown Audio SA V2  $770
   
3. Amp:  JP23  $350
   
4. Wire:  Down 4 Sound 0 gauge wire kit  $140
   
5. Deadener:  Down 4 Sound Deadener:  $100

 

That puts us at $1910, so that gives us some extra wiggle room.  There are lot of other good options out there at this price point.  I went with products from Down 4 Sound because I have personal experience with both the pro-fab enclosure and the JP amplifiers.  The Down 4 Sound organization focuses on the "basshead" market so if you want to make big bass that is where you want to look.  This option includes sound deadener because it is no longer just an option or a good idea.  It is a must have for a system this big, I would recommend spending the rest of your $90 budget on some more.  If you are looking for an alternative to the Sundown Subwoofers, then I suggest that you look at the Kicker Q class 15's. 

Over $2000

You would not know it by looking at social media, but builds this big are pretty rare.  Most car audio consumers are running 10s and 12s on less than 1000 watts.  Remember that cranking up the power means you need to make other upgrades.  If you want to spend over $2k on just the sub stage then you will need to do a lot more research, or visit a local shop.

 

 

Here are the caveats I mentioned above.

1. In this post we are just looking at the subwoofer part of the system.  You will need a head unit or a good line output converter (LOC) to get signal to your subwoofer.  Most amplifiers will accept speaker level inputs.  Not all of them are good.
   
2. These may or may not fit in your car.  Measure the size of your trunk opening (not the trunk, the trunk opening)
3. If you are on a budget you probably don't have tools, so we are looking at pre-fab boxes only.
   
4. Good installation is important.  A lot of budget builds are garbage due to improper installation, tuning, and cheap wire.  
5. If you have some extra money, buy sound deadener.  It makes a huge difference.
   
6. Pay attention to the OHMs and the voice coils.  If you are going to be using a 1 OHM amp you need to make sure you can wire your speakers to 1 OHM 
7. Prices change over time, so you will need to follow the link to get updated prices.
8. I am including an amp wire kit in my budget.  Don't cheap out on the wire.  Go ahead and get OFC wire, avoid CCA.  If you insist on getting the cheaper wire then you will need to go up in size.  Keep in mind that smaller AWG numbers are lager wires.
9. I tried to group these all together so that you can order everything you need from one place. The links in this video are affiliate links, and I may earn a small commission if you make a purchase.