I read most if not all the forum about setting the gains. i used this formula and tested with my dmm AC Volts = sqr(watts x ohms). I'm using two rockford 800.2 800x1 @ 4ohms. When i tested the output with no load bridged it resulted in 85-89 ACV on each amp. based on the formula i should only have sqr(800 x 4)= 56.57 volts. did i miss something cause this is way off and i only had the gains set at 1/3.
The sub is the pioneer premier ts-w5000spl. also can anyone recommend a high spl box size for this sub. I would like it to be slot ported. if that helps
Your math is correct. Feed the amp a test tone within the subwoofer pass band at your max non-clipped input level. 800 watts into a 4-ohm load is accomplished using 56.6 volts AC.
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Support the12volt.comIf you're going to use that method by itself you have to make some assumptions: one is that the power output that the amp is rated for is what it truly is in your installation, and two is that the net load is exactly 4 ohms. Either or both of these can be off. For example, if the actual net load were 4.3 ohms, the result would go up to 58+ volts if you used 800 watts as power in the formula. And so on.
Because of this, you should also use the listening test. With either method you have to 1) use test tones in the frequency range of the subwoofer, and 2) have the volume level of the head unit at the highest output just under clipping level. The test tones should be recorded at a reference 0 db level. This means that the deck output must be tested and set before the amp gains are set.
When you hear the tone change to a clipped tone and then have turned the gain back down enough so that the tone is pure again, read the voltage output. You will probably find that it is much closer to the specified power than what you found. But if you again find a good, steady reading that is higher, then the power output may be more than specified. You won't really know without doing a complete bench test, but you will know that the gains are set right. The relative position of the gains (..."set at 1/3"..) has nothing to do with anything.
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Build the box so that it performs well in the worst case scenario and, in return, it will reward you at all times.
i did use a test tone that went from 100hz to 40hz and i got a read out of around 75-79 on each amp. so if i put that back in the formula from above that equals around 1200 watts. but that can't be correct, or is it.
You are testing voltage with the woofer(s) disconnected, right? Your readings could be correct, but it is probably clipping. Reduce it down to 56.6 volts, then connect your woofers and perform the "by ear" fine tuning as Steve described. Also, before you do anything, go back and ensure your HU is not clipping. You can do this using the "by ear" test also, with the amplifier gain set to minimum.
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Support the12volt.comYou're not looking, but rather listening. When you begin to hear distortion ever so slightly, turn the volume back down until it goes away. That will ensure you a max unclipped signal.
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My ex once told me I have a perfect face for radio.
