i had 2 rockford series 2 power DVC's last week i bought a 700s amp i wired it in a series and they hit hard. the only problem is the amps to powerful and i had to turn down the decibal **** because it sounded like i was gonna blow them. i know they're a little old but they're still supposed to handle 1000w constant and the factory statment says it only has 758w per channel at 2 ohms. do i just not have the amp tuned right or is it the subs?

 

it may be the subs, you should be fine if you wired it in series, because that incraeses the ohm load, instead of decreasing it.

 

The gain **** on an amp is not a volume ****, it is used to match the level between the output of your source unit, and the gain stages of your amp. What you were hearing was distortion, which is difficult to detect at low frequencies, often until it is too late. Your amp can only make so much power out of the 4 volts or so it recieves from your head unit.

If louder is what you are after, then adding drivers is the best way to go. This gets a little complicated, but bear with me. A decibel is not a hard and fast number, it expresses a ratio, such as dB/SPL or dB/W. The decibel scale is logarithmic, meaning as the dB number rises arithmetically, the value, such as SPL increases exponentially. An example would be to make something twice as loud requires an increase of 6dB. If one jet taking off has an SPL of 120dB, then 2 taking off at the same time represents an SPL of 126dB.

Now for the math lesson...You can calculate the number of dB between 2 values, such as voltage, current or SPL by using the following formula.
NdB=20 log(P1/Pr). Where NdB=the number of dB, P1 is the measured pressure, and Pr is the reference pressure. Using this formula, we can calculate the difference in dB between 2 CD units with different output voltages. Say CD player A puts out 3.6 volts, and CD player B puts out 2.8 volts.

First, find the ratio between the voltages by dividing 3.6 (P1) by 2.8 (Pr). The result is 1.2857. Now press the 'log' key on the calculator, and the result is 0.0109. Multiply this by 20 just like in the equation, and the result is 2.18, which represents NdB. CD player A is 2.18 dB louder than CD player B.

The same equation can be used to measure power ratios as well, the only difference is NdB=10 log (P1/Pr). Say amp A has a power rating of 138W and amp B, 276W. Divide 276 by 138 (P1/Pr), and you get 2. Find the logarithm of 2 which is 0.301, and multiply by 10. The more powerful amp is 3 dB louder.

Note that I made amp B twice as powerful for this illustration. It takes double the output power to raise your SPL by 3dB, which starts to get pretty expensive! If you are looking for more bump, I would suggest more subs. I am running 3 JL Audio 8W6's in parallel to a Soundstream Reference 500s in high current mode. By the numbers, this set up should blow the voice coils through the bottoms of the magnets no problem, but it is well set up. My subs have all the power they need and then some, and the amp isn't even breaking a sweat.

I hope all of this helps dispel some myths about SPL and how to go about getting more.

 

nice post, very imforative.

 

i didn't do anything with the gain i simply turned down the remote bass **** which is a small adjustment in the 45HZ range. it goes from 0-18db.