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J2phat4u

Reactive vs. Nominal

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I am trying to figure out my SP4 15's when it comes to how many different wiring options i have. My subs are dual 2 ohm subs and right now i am wired to 1.4 ohms at the amp. Seems i cant wire any lower without the amp going into protect. Was just curious about nominal vs. reactive when it relates to my setup.

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There is a difference between dc and ac resistance. Impedance is rated over a usable frequency range.

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so that means depending on the frequency the impedance changes. If they are d2 they are d2 not 1.4

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^^^ Exactly.  Impedance and "reactive" resistance is basically the same thing.  Regular resistance, like a resistor in a circuit, doesn't change with a given frequency, voltage, current, etc.  Any coil wound resistor/resistance has an impedance that changes with the AC frequency that goes through it.  DC current sees a constant resistance value though and is typically lower than AC impedance.  As Julian mentioned the impedance value that is listed is basically like an average for a given range of frequencies.

 

 

1.4 ohms would be about 2 ohms nominal impedance.  You are measuring that resistance with the subs disconnected from the amp, correct?  Three dual 2 ohm subs could be wired to .33 ohms (all parallel), 1.33 ohms (series coils/parallel subs), 3 ohms (parallel coils/series subs), and 12 ohms (all series).  Can be viewed here.

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Yeah I just don't know how my amp would take sitting at .33 ohms?

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Most amps won't do it daily. My 9s Would play at .25 but required me to play above 50hz or they'd protect instantly

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Yeah I feel you....I am going to re-cone them to dual 1's and total out to 4. Them run 2 Crossfire 8k's to all 4 and see how she wangs....bananaDance.gif

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