Beginner
Skar Audio
Skar Audio RP-800.1D
Price varies, check the listingA class D monoblock with a bass remote included, which is the usual first subwoofer amplifier.
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RMS vs Peak Power Calculator
Quick answer
Peak power is a marketing figure and RMS is the measured one. A subwoofer advertised at 1,200 watts max is typically rated somewhere near 300 to 600 watts RMS, and the difference between 300 and 1,200 watts is 6 dB, which is less than it sounds.
Result
Difference in level 3 dB Published figure
Power ratio 2 x
Output voltage at the rated power 31.62 V Published figure
Doubling power is always 3 dB Published figure
Ten decibels is roughly a doubling of perceived loudness, and ten decibels takes ten times the power. This is why the jump from 500 to 1,000 watts is far less dramatic than the numbers suggest.
The formula
dB difference = 10 x log10(P2 / P1)
CTA-2006, formerly CEA-2006, is the published standard: RMS power at 1 percent distortion into a stated impedance at 14.4 volts. A product that quotes a CTA-2006 figure has been measured. A product that quotes only a max or peak number has not told you anything you can use. There is no fixed ratio between the two, so no calculator can convert one into the other, and this one does not pretend to.
The figures above are computed with these exact inputs: Amplifier RMS power 500 W, Compare against 1000 W, Load impedance 2 ohms.
What this calculator assumes
Some of these are published physics or manufacturer figures and some are conventions. They are not the same kind of number, so each one is labeled.
| Assumption | Kind | Where it comes from |
|---|---|---|
| CTA-2006 (formerly CEA-2006) | Published figure | CTA-2006 (formerly CEA-2006), the mobile amplifier power measurement standard: RMS power at 1 percent THD+N into a stated impedance at 14.4 volts |
| SPL = sensitivity + 10 x log10(power) | Published figure | SPL = sensitivity + 10 x log10(power), the logarithmic power relation |
Gear that matches this result
Every card below is in the page source. The calculator re-ranks them against your numbers and marks anything that falls short of what you just calculated.
Beginner
Skar Audio
Skar Audio SA-1000.1D
Price varies, check the listingA thousand watt class D monoblock at the budget end of the range.
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CT Sounds
CT Sounds CT-1000.1D
$159.99A published 1,000 watt RMS figure rather than a peak number, in a compact chassis.
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Taramp's
Taramps Bass 1200
$159.00A published 1,200 watt RMS at 1 ohm, which is the load most dual 2 ohm subwoofers end up at.
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Stetsom
Stetsom Bravo Bass 1200
$159.99A 1 ohm stable monoblock with a published RMS rating and a crossover on board.
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Skar Audio
Skar Audio RP-2000.1D
Price varies, check the listingTwo thousand watts needs a charging system upgrade first. Buying this before the big 3 is the wrong order.
Check price on AmazonFrequently asked questions
- How does the rms vs peak power calculation work?
- dB difference = 10 x log10(P2 / P1). CTA-2006, formerly CEA-2006, is the published standard: RMS power at 1 percent distortion into a stated impedance at 14.4 volts. A product that quotes a CTA-2006 figure has been measured. A product that quotes only a max or peak number has not told you anything you can use. There is no fixed ratio between the two, so no calculator can convert one into the other, and this one does not pretend to.
- Are these figures published or are they rules of thumb?
- Both, and the page labels which is which. The Helmholtz port relation, the Thiele/Small alignment equations, cone area geometry, Ohm’s law, conductor resistance and ampacity, and manufacturer specifications are published and are labeled as such. Amplifier efficiency, cabin gain, the farad per thousand watts rule, port area per cubic foot and coverage percentages are conventions with no measurement behind them, and they are labeled as conventions.
- Why does this calculator sometimes refuse to give an answer?
- Because there genuinely is not one. A port can be too large in area for the box and tuning asked of it, a vented alignment stops describing a useful box outside a Qts range, and a sealed box cannot produce a total Q below the driver’s own. In each case the calculator returns nothing and explains why, rather than extrapolating past the end of a published relation.
- Do I still need an installer if I use this?
- Many owners do their own 12V work, and these are the figures that work is sized from. What matters is that a car battery delivers hundreds of amps into a short without hesitating, so the main fuse goes within 18 inches of the battery positive terminal and the battery comes off before power wire goes in. If any of that is beyond what you want to take on, a professional installer is money well spent.
Researched guidance, not professional advice. These results are planning figures from published relations and manufacturer specifications. Fit the main fuse within 18 inches of the battery positive terminal, because that fuse protects the wire and the wire is what starts a fire. Disconnect the battery before running power wire, use a grommet through every piece of sheet metal, and remember that sustained high sound pressure causes permanent hearing damage.