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Ex: How to select a speaker that matches my current audio system?

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Amp Wire Calculator

Our Amp Wire Calculator helps optimize your amplifier's power output by recommending properly sized (AWG) wires. Using your current speaker and power wire, current amp power is calculated, allowing you to see any potential losses (in Watts) with undersized cables.

STEP 1:

Performance Verification Certificate (PVC)

PVC

Start by locating the Performance Verification Certificate (PVC) supplied with your Rockford Fosgate amplifier. We'll use data from the PVC to determine how much current your amplifier will draw from the vehicle's charging system.

STEP 2:

Efficiency

Efficiency, in amplifier engineering, a ratio of the amount of power produced by an amplifier to the amount of power put into it.

$$Efficiency \% = {Amplifier Output Power (watts) \over Amplifier Input Power (watts)}$$

therefore

$$Input Power = {Output Power (Provided On PVC) \over Efficiency (Provided On PVC)}$$

Enter Outout Power and Efficiency from PVC

Total RMS Watts (printed on bottom of PVC)

%


STEP 3:

Ohm's Law

Ohm's Law states that:

$$Power(watts) = {I(amps) \cdot E(volts)}$$ therefore$$I(amps) = {Power (watts) \over E (volts)}$$

Let's use Ohm's Law to calculate exactly how many amperes of current it will take to produce 100 watts of input power at the following battery voltage:


Enter Battery Voltage from PVC to calculate total amps:

STEP 4:

Music

Because music is dynamic in nature, it will be easier for the amplifier to reproduce than test tones. Our testing has shown that it is typical for an amplifier to consume on average roughly 50% of its maximum input current on such.


So, this amplifier is likely to consume, on average, the following amount of current when driven to clipping with music:

$${100 Watts (Power)\over 2 Volts(E)} = 50 Amps(I)$$ 50% gives you the current draw of the music$$ 25 Amps(I)$$

Take the necessary steps to upgrade the vehicle's charging system appropriately. This would include, but is not limited to:


  • Appropriately sized battery
  • Additional storage in the form of capacitance
  • Appropriately sized alternator
  • Properly upgrade power & ground cables

STEP 5:

Wire Calculation

This section will help determine wire gauge size needed from your vehicle's charging system to optimize electrical current delivery to your amplifier.


How is it calculated?

Wire Resistance Chart

This chart shows the ammount of resistance for each wire size. Using shorter wire legnths and/or larger wire will optimize amplifier power output.

AWG Ohms/Foot
2/0 0.00007
1/0 0.00011
1 0.00007
2 0.00015
4 0.00029
6 0.00047
8 0.00074
10 0.00118
11 0.00148
12 0.00187
13 0.00236
14 0.00296
15 0.00374
16 0.00472
18 0.00748
20 0.01182
22 0.01888
Amplifier power in Watts from PVC
10 Watts RMS
Channels
Ohms
Feet
Feet

Now select the following wire sizes ...

AWG
AWG


Actual power delivered to speakers:10 Watts RMS


Power lost due to inadequate wire sizes:(0) Watts RMS Lost!!


change speaker/power wire size to re-calculate