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  #1  
Old 12-11-2010, 08:37 PM
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Need some things explained to me about amps and subs

When It comes to everything else except audio I like to think of myself very versitile in familiarising myself with things I dont know but when it comes to this audio stuff im just lost!

Here is what im dealing with ive got 2 rf p3sd410 ive got them hooked to a
p200-2 amp and well as you can guess it doesnt hit very hard... I got the amp when I only had the one sub and then when my buddie totaled his truck he gave me the other and I made the box and tied it in. Let me also mention that I have a regular cab 05 and am tall(seat all the way back) so this is why I went with the shallows.

I want to upgrade my amp for the subs... HERE IS WHERE I DONT UNDERSTAND the subs are good for 300rms which to my understanding means that you can run the subs at a 4 ohm load off of a 600 watt amp? im guessing here honestly BUT I HAVE READ that there are people who say to run them with a 1000 watt amp?? doesnt make sence to me I would think that it would blow the subs or amp...to go along with this they also say that properly adjusting the gain will keep you from blowing anything??You could educate me or just tell me what to do Id rather both but I want a amp that is going to SAFELY (little chance at all in blowing) make my subs live up to there potential
and then when I get the new amp for the subs I would like to power my 6x9s with the p200-2 will that sound ok? will be 50watts per speaker if im correct and they are rated at 65rms (rf 6x9s 3 ways)

thanks for helping a newb out
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  #2  
Old 12-12-2010, 12:39 AM
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Lets say "Amp X" is a 1000W amplifier.

1000W Peak or RMS makes a difference. RMS is the number to look at. Lets say its 1000W RMS just to make this easier. That now means 1000W RMS at 1 Ohm. When the impedance(resistance in the circuit) of the subwoofers is 1 Ohm, the amplifier will make 1000W of power. Now lets say you are running them at a 2Ohm resistance, the amplifier will only be making 750Ws. So now that 1000W amplifier will really only be sending 325Ws to each sub, not 500. At 4 Ohms you are really losing power. You might get 500Ws out of the 1000W amplifier, or 250Ws to each subwoofer.

Thats as simple as I can make it for that part. As for the gain, turn the gain **** on the amp all the way down(if you have a remote gain **** for your dash, turn it all the way up as well as turning the one on the amp down.) Now pick the hardest hitting sound you have, and turn the volume to the max you will listen to. Most people say around 75-80% of max volume, otherwise it might start getting a little fuzzy which is normal at 100%. Anywho, turn the volume **** up as high as you plan on going, play that hard hitting song, and start turning the gain **** on the amplifier up until the sub starts to clip. Turn it down just slightly from where it starts to clip, and don't ever touch that **** again. Now you will use the remote gain **** that you can install in the dash to adjust the bass later on. That is how you adjust the gain.

As far as bass boost and other such features, make sure they are off and do not turn them on. They are meant for songs like Beethoven and such which don't have a lot of natural bass. Nowadays, all songs have bass in them, so bass boost shouldn't be used.

I have an amplifier thats rated at 9100Ws and we hooked it up to a friends subs just to test it one time, he has around a 500W set up. We kept it down low so it didn't destroy anything, but you can use the most powerful amp in the world on the weakest subwoofer as long as the gain is set properly.

If you have any other questions, just PM me and I will help out if I can.


EDIT- 2 300W subwoofers running at 4 Ohms on a 600W amp would probably only be getting 100-150Ws each depending on the amplifier.
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Last edited by Ford12508; 12-12-2010 at 12:43 AM.
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Old 12-12-2010, 11:10 PM
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Power handling will be application dependent. Put them in a larger enclosure and efficiency increases while power handling decreases. A driver fails because it either reaches it's thermal or mechanical limits. In the case of the RFs you have, they are suspension limited and you will hear them straining before they fail thermally.

As for you amp question, it's not all that simple. You may have a 1000 watt amp, but your drivers may only need half of that to reach their excursion limits. Also, keep in mind you need a 3dB difference to notice by ear a change in volume, which is equal to doubling drivers, or power, so if you have 750 watts going to your drivers, you hear a difference until you get near 1500 watts.
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Old 12-13-2010, 12:42 PM
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and as ford was saying.... Find out what ohm load your subs end up at and then look at your amps manual and find out what it puts at that ohm load...

some amps have differnt damping factors and dont allways change rms/watts per ohm load

like 4 ohm 200 rms
2 ohm 400 rms <--- see how it doubled..

not all amps do the same
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Old 12-15-2010, 01:14 AM
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Quote:
Originally Posted by ssj4shane View Post
some amps have differnt damping factors and dont allways change rms/watts per ohm load
Nothing to do with dampening factor.

Quote:
like 4 ohm 200 rms
2 ohm 400 rms <--- see how it doubled..

not all amps do the same
All amps should do that in theory thanks to Ohm's Law. No amps really do, also thanks to Ohm's law. There are plenty of amps that are rated to double power when the load halves, but in order to make their rated power into the lower impedance they usually make a good deal more than rated into the higher impedance.
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Old 12-15-2010, 08:09 AM
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Another thing to add is that if you buy cheap amps, they can do less than what they say they can do, or struggle to output what they say they can. I have an 800W 4 channel amp that puts out nearly 1kW when it was bench tested, which for some amps is not unusual as helotaxi said, they can do more than what they say they can.
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Old 12-15-2010, 01:11 PM
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Quote:
Originally Posted by helotaxi View Post
Nothing to do with dampening factor.


All amps should do that in theory thanks to Ohm's Law. No amps really do, also thanks to Ohm's law. There are plenty of amps that are rated to double power when the load halves, but in order to make their rated power into the lower impedance they usually make a good deal more than rated into the higher impedance.

Nice to see a familiar name around here.
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Old 12-15-2010, 02:09 PM
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oh how dis hearting.... after typing up several paragraphs... I lost it all.. ahhhh
Maybe I'll type it up again.... later and try to repost.
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Old 01-10-2011, 08:34 PM
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Originally Posted by tirefryr View Post
Nice to see a familiar name around here.
Ditto. You'll also be happy to know that I have a pair of BMs going in my new screw.
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Old 01-10-2011, 08:34 PM


 
 
 
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