Doubling Power - 3 db Increase?

[Cpyder 10+ year member]

Where did the notion that doubling power results in a 3 db increase?? Sound is usually represented a logarithmic scale. Increasing 10 decibels would require 10x your current power, right?

So if you're at 120db, it should require 10x your current power to reach 130db.

Can anyone prove or disprove the double power = 3db increase? With math pref.

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[n2audio 5,000+ posts]

Looking at it with basic math (since I simply cannot absorb anything having to do with logs)

If you have your 120 db at, for example, 500w, you'd have 123db at 1000w, 126db at 2000w, 129db at 4000w, and 130db at 5333w (4000+4000/3), or 10.66x the 120db power.

 

[Cpyder 10+ year member]

No, I understand the concept. I just want to know if it's true. I'm quite sure it's not.

 

[funkyab 10+ year member]

look at jacobs post earlier comparing the sundowns for a real world example.

 

[DBDRAGGUY 10+ year member]

Strictly mathematical theory.

In reality such as a car audio enviorment there are too many variables to accuratley predict what effect doubling your power will have.

 

[Lakota 5,000+ posts]

That is the theory, and yes it can be proven with logarithms. I actually have that equation around here somewhere, I used it in calculus. But, you must remember that that's theory and a rule of thumb. It doesn't always work out that way in real life

 

[shakinghorizons]

the db scale is not linear. once you reach around 150db you have to start doubling power to get higher numbers. 120 db+ between there is not anywhere near 10x the power to get 130 db, it don't take 5333w to get 130 db. //content.invisioncic.com/y282845/emoticons/crap.gif.7f4dd41e3e9b23fbd170a1ee6f65cecc.gif

 

[KyleBechtold 5,000+ posts]

if you kept the same scenario and only increased power then yes.. but if you change anything else its out the window

 

[Supergumby5000 5,000+ posts]

Strictly mathematical theory.

In reality such as a car audio enviorment there are too many variables to accuratley predict what effect doubling your power will have.

this

In a perfect environment, it will be true. In a situation like a vehicle, factors such as imaging, pressure levels, flexing, interference, cancellation, etc etc come into play

 

[bose301s 5,000+ posts]

Like has been said, in a perfect world doubling power is a 3dB increase, however in the real world doubling power to a sub also increases the heat created, increasing power compression and thus not actually gaining you a full 3dB increase.

 

[Rashaddd 5,000+ posts]

the db scale is not linear. once you reach around 150db you have to start doubling power to get higher numbers. 120 db+ between there is not anywhere near 10x the power to get 130 db, it don't take 5333w to get 130 db. //content.invisioncic.com/y282845/emoticons/crap.gif.7f4dd41e3e9b23fbd170a1ee6f65cecc.gif

fail.

Like has been said, in a perfect world doubling power is a 3dB increase, however in the real world doubling power to a sub also increases the heat created, increasing power compression and thus not actually gaining you a full 3dB increase.

this.

also, dont look at 'real world' examples and generalize based on those either...If I double the power to my MJ's I might gain .5-1db and some smoke. If I go from 800w to 1600w on a sub capable of taking 4000w, I will likely come pretty close to a 3db gain, I'd guess around 2-2.5db, maybe a little more, maybe a little less, there are too many examples and no two situations will be exactly the same...not to mention our measuring of true power isn't always accurate, so chances are you're off to begin with.

 

[RAM_Designs 5,000+ posts]

120 db+ between there is not anywhere near 10x the power to get 130 db, it don't take 5333w to get 130 db. //content.invisioncic.com/y282845/emoticons/crap.gif.7f4dd41e3e9b23fbd170a1ee6f65cecc.gif

No wai?!?!? It was pretty obvious he was just using it as an example, showing how it theorhetically takes 10x the power to get 10db in gain.

 

[dvrmstrng 5,000+ posts]

so the same can be said that going from sealed to ported with the same power doesn't necessarily give you +3db

 

[Rashaddd 5,000+ posts]

so the same can be said that going from sealed to ported with the same power doesn't necessarily give you +3db

this 'rule of thumb' is even more off. You can gain less than 3db, you can gain far more than 3db. Depends on a million other things, including the design of the ported box and how well it aligns to the sub.

 

[DBDRAGGUY 10+ year member]

so the same can be said that going from sealed to ported with the same power doesn't necessarily give you +3db

This is actually closer to the truth,mainly because the enclosure will become more efficient going from sealed to a reflex.