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I'd like to see the math on why the amp can't be more than 18W with a 12-14v input. By that reasoning, standalone amps would all be 18W per channel. I'm willing to bet that most in-head amps AREN'T, but can't be is a whole different matter. The guts to do otherwise are getting cheaper and cheaper.
 

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Ok, here's the maths.
Assume an input voltage to the amp stage of 12v on full power ( it will actually be less than that.
Assume NO power losses whatsoever (this isn't going to happen)
Assume an eight ohm nominal impedence speaker.
12v with 8 ohms is 1.5 amps or 18 watts.
Iirc rms is peak x.707 so around 12.5 rms if my sums are right
Assume a 4 ohm speaker and the results are double - so around 25 watts rms assuming no losses which is impossible.

The only way to get higher outputs is to increase voltage with an inverter or reduce speaker impedence (which can blow an output stage if it isn't matched).
 

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Something is amiss here. Maybe I'm missing the point of this thread. The input voltage to the amplifier has nothing to do with the output voltage to the speakers. Not to mention that the speakers are not receiving DC voltage. You can run hundreds of watts output with only 12VDC input. The amplifier just draws more current on the 12VDC input.
 

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You can run hundreds of watts output with only 12VDC input. The amplifier just draws more current on the 12VDC input.

Not into a single 4ohm or 8ohm speaker, you can't.
 

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Yea, and drawing from my experience with Home Theater...if you put , let say 10 watts power, into a reasonably sensitive speaker, it will be very loud in the small chamber we call the interior of our vehicle. Btw, I have the Trailhawk, 2015 6 speaker system and those speakers are NOT reasonably sensitive...a bit on the low side.
While good speakers can always benefit from more power (up to a point), I don't think the Amp is the weakest link in the sound system. Maybe not true for the Beat system...
 

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Sure you can run a hundred watts into a single 4 ohm speaker - even 2 ohms. Audiophiles do it all the time. Just look up some subs on Crutchfield. I just did, and quickly found a $40, 10inch Jenson, 4 ohm sub woofer that could handle 250 watts. The speaker just needs to be designed to handle it.
 

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Sure you can run a hundred watts into a single 4 ohm speaker

Not with 12 volts you can't. (Unless you are using an inverter to boost the voltage. Then it wouldn't be 12 volts).
 

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Sure you can run a hundred watts into a single 4 ohm speaker

Not with 12 volts you can't. (Unless you are using an inverter to boost the voltage. Then it wouldn't be 12 volts).
I get that, but I'm not sure why you are stuck on the "12 volts". The voltage going to the speakers has nothing to do with the 12 volt direct current car power going into the amplifier.
 

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In order for DC to get sufficient amperage, it requires a larger diameter wire. Most factory head units are wired with 16-14 gauge wire. Using 14 gauge wire with 10' length, you can only get 180 Watts at 15 Amps. That's not taking resistance (Ohms) into consideration. I'm not surprised at all that you can only get 18-20 Watts per channel.

The factory amp in the Renegade is a little over 500 Watts. With that in mind, it would require at least 10 gauge wire if not 8 gauge. If you install a 1000 watt aftermarket DC amp, you would have to run 4 gauge wire in order to provide enough current to power the amp.

For those that don't understand, the larger the wire, the lower the gauge number.
 

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Doubtful the factory amp delivers 500w RMS. I would want to see a bench test or examine it myself before I take it as fact. The 500w could be a peak to peak rating....
 

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Sure you can run a hundred watts into a single 4 ohm speaker

Not with 12 volts you can't. (Unless you are using an inverter to boost the voltage. Then it wouldn't be 12 volts).
Boost circuits aren't exactly rocket science. Nor prohibitively expensive. Nor is it required to actually be a DC to AC inverter circuit. DC-DC boost circuits exist just fine. Not to mention that running speakers isn't simply a power circuit, and the voltage fluctuates and all sorts of other fun stuff.
 

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Boost circuits aren't exactly rocket science. Nor prohibitively expensive. Nor is it required to actually be a DC to AC inverter circuit. DC-DC boost circuits exist just fine. Not to mention that running speakers isn't simply a power circuit, and the voltage fluctuates and all sorts of other fun stuff.
Completely correct here.

I've just gotten one of these for my daughter, but I haven't gotten into the radio much yet.

Without knowing more about how the radio is working yet, I can only speculate, but there is no reason to believe that the speaker output is limited to 12V.

I work at a semiconductor design center, specifically in the mobile audio group. We make the audio amplifier chips that go into mobile gadgets, which generally run at around 3.7V supply voltage. Using built-in boost circuitry, we have no trouble running the speaker output at 12V and can easily drive a 4 ohm speaker to surprisingly loud levels with >90% efficiency, all from a tiny little Class-D amplifier less than 2mm square.

The stock HK amplifier in my Challenger uses a Class-D amplifier that drives the speaker outputs to more than 90V, and it's powered by the 12V line. The 12V input really has no bearing on the actual speaker output.
 

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Every car amp is 12 volt by my understanding. All run from the battery. With 10 gage or 12 gage wire. Then the amp uses the transformers to convert the power from the signal input low or high. To output a stronger signal to the speaker . The 12 volt supply has nothing to do with the output power. Same as a house amp uses 240 volt or 110 depending where you are. And the uses transformer to convert to output power? It doesn't supply 240 volts to a speaker.
 

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Discussion Starter · #19 ·
I still know only enough about car audio to be dangerous. But I found this and other sites like it to download audio test files to a thumbdrive and play over the headunit.

I can hear where highs and mids are coming from the front speakers and bass from the sides and rear. Lots of things to do to help learn a little more about the system installed and after speaker replacement.

Just FYI.

http://www.audiocheck.net/
 
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