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One sub or 2?

Printed From: the12volt.com
Forum Name: General Discussion
Forum Discription: General Mobile Electronics Questions and Answers
URL: https://www.the12volt.com/installbay/forum_posts.asp?tid=470
Printed Date: August 17, 2025 at 1:32 PM


Topic: One sub or 2?

Posted By: sgf323
Subject: One sub or 2?
Date Posted: April 26, 2002 at 10:10 AM

According to theory...  could someone please explain to me what would be louder and why.

Ignore any other considerations except the ones I give...  don't worry about the car's acoustics, etc...

Scenario A:  125watt RMS amp running into a single 10" Sub.

Scenario B:  250watt RMS amp running into a single 10" Sub.

Scenario C: 125watt  RMS amp running into one 10" sub and another 125watt RMS amp running into another 10" sub.

Assume that all amps are equal, except for Scenario B being twice the power of A and C.  Also assume that all boxes and subs are identical.

If Scenario A yields X db then what does Scenario B and C yield?

These are my thoughts... but I have been told that they are wrong... I would appreciate if someone could tell me why!

Since in Scenario B you are doubling the wattage over A, you gain 3db.  So Scenario B yields X+3 db.

For Scenario C, I can't decide if you gain 3db or 6db.  Could someone explain which and why?

thanks




Replies:

Posted By: pat28ca
Date Posted: April 26, 2002 at 10:32 AM
essential, theoretically, you are doubling the power compared to scenario a. it will be closer to "b".  but you also have to take into consideration that everything will affect the db. acoustics, wire size, gain, head unit, rca cale. you already know this. but efective ly you'll probably be closer to x db +3 in this theoretical scenario. similar to having a dual voice coil sub. the most correct answer given the parameters of the question.




Posted By: pat28ca
Date Posted: April 26, 2002 at 10:36 AM
one last thing. remember it's all about displacing air. so if the surface of one speaker displaces x amount of air , then two spakers at the same wattage will dispalce twice the air, hence 3 db increase. same speaker twice the power , speaker moves twice as far. hence 3 db again. but this spaker would be closer to x max. hence distortion. in a sense and this is all according to parameters outlined




Posted By: NyxBass
Date Posted: April 26, 2002 at 12:36 PM
A combination real world/theory: With double the wattage, you can assume a 3db increase, but it all actually depends on the driver. It may or may not be able to use that power to full extent. Two drivers is a safer bet in getting you 3db min (and there's also , with low frequencies, a point source gain, that, if they are close enough (1/8 wavelngth or something) you can get another 3 db or so as the waves reinforce each other) and you are garaunteed that double the come will move, assuming the drivers and amps are the same. In real world, the double cones almost undoubtedly would be louder.

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/NyxBass




Posted By: NyxBass
Date Posted: April 26, 2002 at 12:36 PM
See https://www.installer.com/tech/conearea.html for more info.

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/NyxBass





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