2 subs twice as loud?

[simon21 10+ year member]

OK, lets say I have a 300W amp. If I run 2 subs at 150W each vs. 1 sub at 300W, they are both going to be just as loud as each other?

 

[helotaxi 5,000+ posts]

It depends on how the coil of the subs handle power and on the mechanical aspects of the design as well. The 2 subs will probably be just a bit louder (you would need a meter to tell) because the single sub would be entering into power compression and becoming less efficient as you increase the power. If you can address the phase cancellation problem it would theoretically be easier to get louder with more subs with less power going to each. As you increase power per sub, the efficieny of that sub decreases and you stop getting the full 3dB out of each power doubling really quickly. Of course the more subs you add the more phasing becomes an issue so there is no easy route to loud.

As far as the 10dB to be perceived as twice as loud, once you figure in scale weighting to compensate of the inconsistency of the human ear across the frequency spectrum, it is 10dB, that is scaled standard.

 

[nweibley 10+ year member]

As far as the 10dB to be perceived as twice as loud, once you figure in scale weighting to compensate of the inconsistency of the human ear across the frequency spectrum, it is 10dB, that is scaled standard.

I understand, but you have to understand there are people with very sensitive ears (my friend Joe for example) and then you have people like my our building mgr who used to be in a band and has very insensitive hearing. I personally don't notice much of a difference in sound output over 150 dB, I just notice more rattling, things becoming more difficult to see, etc.

Word. I'm going home from school now.

 

[helotaxi 5,000+ posts]

Well, there are always exceptions, those that fall several standard deviations from the norm...

 

[tobz 10+ year member]

Yup, we will call them "out-lie-erz". They are what makes this world so messed up. Or maybe they keep it from being perfectly normal? Or maybe math isn't everything...

Or maybe it is? Well, basically said, just remember, two RE's are effectively twice as loud as a case of funky pups unless you have them inverted with a spoiler.

T.J.

 

[n_derr]

actually its a logarithmic scale.

Thanks for some sense in this thread. I believe the equation is a simple high school physics equation : L=10log (I/Io)

L is the soundlevel (dB)

I is the sound intensity (watts/ sq meter)

Io is the threashold oh human hearing (the low end, of course)

If you plug the correct numbers in the correct places, you'll find that doubling the number of speakers will be 10log(2) times louder or 3.01 dB (slightly more than 2x) louder.

There's your answer.

 

[454Casull 10+ year member]

2 subs wouldn't cancel each other out to some degree?

Not if they are firing in phase. If they were firing out of phase, yes, that would be true.