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power vs. subs

Printed From: the12volt.com
Forum Name: Car Audio
Forum Discription: Car Stereos, Amplifiers, Crossovers, Processors, Speakers, Subwoofers, etc.
URL: https://www.the12volt.com/installbay/forum_posts.asp?tid=125602
Printed Date: May 05, 2024 at 2:52 PM


Topic: power vs. subs

Posted By: rogggg1020
Subject: power vs. subs
Date Posted: January 10, 2011 at 10:22 PM

here is the question my wife asked myself and i couldnt find it here for her to read.....here goes....its the power not the amount of subs right??? i mean if my amp pushes 160 rms a channel powering 2 subs but bridged is 480 rms 4 ohm would i rather get one sub that handles 480 or 2 subs handleing 240 a piece??? should i go with the one sub or two??? if this is already on here then im sorry i just couldnt find it when i did the search on power or number of subs to clarify this to my wife

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roger (95 cougar 4.6 stock expect the stereo)



Replies:

Posted By: stephan1234
Date Posted: January 11, 2011 at 2:02 AM
it is better to have 2 subs because 2 subs have more surface area witch mean they move more air and moving more air means more spl output .say you have a 2 channel amp that pushed out 160watts per channel at 4 ohms and 240 at 2 ohms and in mono 480 at 4 ohms like as i understand the one you describe is than if you use two daul 4 ohm subs witch will give you 2 ohms each than you would get 3 db spl more than with one 4 ohm sub with the same efficiency as the other 2 subs




Posted By: yimke
Date Posted: January 11, 2011 at 6:35 PM
Without getting too much into it....

It's essentially the same. Double the subs, you usually double the power output IF you wire it in parallel. Two 4 ohm subs = 2 ohms. This is because resistance DECREASES as units are wired in parallel.   According to ohms law P=IxV and I=V/R so P=V2/R. If your voltage is the same (14 or 12 volts)you will square that will be the SAME regardless. And you divide by a smaller number 4 vs. 2. You get a LARGER answer. Which equals P for Power.

HOWEVER, this is not true if you had two subs and wired them in series. Then your resistance would INCREASE to 8 and your would have 1/2 as much power as your sub initially could produce.

This is assuming the same enclosures, environment, amp gain, power drop, etc.

So basically power determines total work performed. However, adding subs can possibly alter the output IF done correctly and in moderation.




Posted By: rogggg1020
Date Posted: January 11, 2011 at 6:51 PM
so if i was to use 2 8" subs where the area of the subs would be 100.48" and have the 240 watts rms going to each of them that would be better than 1 10" sub where the area is 78.5 with 480 watts rms going to it...or 3 8" with an area of 150.72" with them getting the same 480 watts rms combined then that would be better than getting 1 12" with the area being 113.04"....right?????

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roger (95 cougar 4.6 stock expect the stereo)




Posted By: yimke
Date Posted: January 11, 2011 at 7:17 PM
Now you're complicating the situation because you are using different size subs.

Just give us model numbers of the amps, subs and box cubic feet and we can tell ya which would be better.




Posted By: rogggg1020
Date Posted: January 11, 2011 at 7:38 PM

im just trying to see which one would be better for me so when i do decide on what i want i wont have to go thru all of this, and the first reply talked about surface area, i know a bigger sub would have more surface area but 2 smaller ones would have more surface area than the one, im trying to make my box smaller but with higher sound output( i know thats almost impossible) where 2 entry level with 160 rms going to each compared to 1 pro sub with 480 rms to it ( i hope that makes since to somebody..im still trying to figure it out too)



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roger (95 cougar 4.6 stock expect the stereo)




Posted By: stephan1234
Date Posted: January 12, 2011 at 2:48 AM

go to this link and look under the selection 31 speakers

 https://www.bcae1.com/

maby it will help you understand

1 sub say with a sensitivity rating of say 90dbspl at 1 watt at 1 meters will play just as loud as 2 sub with a sensitivity rating of 87dbspl at 1watt at 1meter

with the one 90db sub getting 480 watts

and if the total watts of the  87db subs is also 480 watts

so it is always best to try and get a sub with the best sensitivity like you said 2 entry level sub will maby have a less rating that one more expensive pro sub






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