Educate me: Same cone area, increased power = louder?

[Supergumby5000 5,000+ posts]

This may be a dumb question, but i would love some knowledge on the subject

Lets compare two substages, for the sake of the arguement, both substages consist of two 12" subwoofers.

One of the substages is running 600RMS subs, each recieving 600RMS.

The other substage is running 2000rms subs, and each sub is receiving that 2000rms.

Assume both subs have the same volumetric displacement at their max power, and both are receiving max power. Both are in the same vehicle.

What makes the 2000rms substage "louder" SPL wise? The only thing i can think of is the greater force required to move the more beefy subwoofer, but at the same time that confuses me in terms of an SPL meter measuring pressure, if the same amount of air is being moved.

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[CobraStang98 10+ year member]

I've never really thought of it that way, I'm interested in seeing what people have to say about this...

 

[squeak12 10+ year member]

If that is the case, that would make the first set up more efficient than the second? If they have the same volumetric displacement, I would think that would mean the with their respected rms power, each of them would have the same excursion. What makes you think that one would be louder than the other?

 

[Supergumby5000 5,000+ posts]

If that is the case, that would make the first set up more efficient than the second? If they have the same volumetric displacement, I would think that would mean the with their respected rms power, each of them would have the same excursion. What makes you think that one would be louder than the other?

mainly the reason im asking is look at SPL vehicles. Most of them have subs that can take a huge amount of power, but why? What is the advantage of an 18" sub handling 3krms, when you could have a different 18" sub with 200RMS do the same thing in terms of displacement?

 

[CobraStang98 10+ year member]

If companies could make a woofer that was efficient enough to be as loud as a 3kw woofer @ 200 watts them i'm sure everyone would run them.

 

[Supergumby5000 5,000+ posts]

If companies could make a woofer that was efficient enough to be as loud as a 3kw woofer @ 200 watts them i'm sure everyone would run them.

yeah but what do you mean by efficiency? the sub itself or the install or what? We are talking identical environments here

if a substage is displacing 1 cubic foot on 10krms, and another is displacing 1cubic foot on 500rms, where is the efficiency making an effect?

 

[tinmanchris217 10+ year member]

Good question. I'm quite interested.

Since everyone is bashful, here's a vague start. A greater pressure is created at the cone. More cone inertia, pushed with a faster initial acceleration (higher motor strength) should yield higher pressure, assuming the same air volume is covered by the cone.

Similarity to a race-car suspension vs. cadillac... you can drop a Lamborghini from 4 feet in the air, and it will compress alot less than a Dodge Ram. Same force, similar weight, different stiffness and deceleration.

 

[Supergumby5000 5,000+ posts]

Good question. I'm quite interested.
Since everyone is bashful, here's a vague start. A greater pressure is created at the cone. More cone inertia, pushed with a faster initial acceleration (higher motor strength) should yield higher pressure, assuming the same air volume is covered by the cone.

Similarity to a race-car suspension vs. cadillac... you can drop a Lamborghini from 4 feet in the air, and it will compress alot less than a Dodge Ram. Same force, similar weight, different stiffness and deceleration.

This is exactly what i was thinking, i just wanted clarification. Thats the only sense i could make out of competition subs having crazy suspension/spider setups.

 

[xtremebassjunky 10+ year member]

but 30 hz can only travel at 30 cycles per second. no faster or less. so i would imagine there is more to it than that

 

[SlainNothing 10+ year member]

30 cycles per second is the length of the wave.... now what about the height?(amplitude)

 

[power-fanatic07 5,000+ posts]

thats like saying a pinto with 200 horses would out run a gsxr with 200 horses :lol:

 

[xtremebassjunky 10+ year member]

yes, but it is an ac motor so it is so supposed to move at the input frequency. the music being reproduced is the frequency thats all.

are you referring to the excursion? it would only be a piece of the answer i would imagine having to do, obviously, with the amplitude of the waves if thats what you mean.

 

[mrogowski 5,000+ posts]

This may be a dumb question, but i would love some knowledge on the subject
Lets compare two substages, for the sake of the arguement, both substages consist of two 12" subwoofers.

One of the substages is running 600RMS subs, each recieving 600RMS.

The other substage is running 2000rms subs, and each sub is receiving that 2000rms.

Assume both subs have the same volumetric displacement at their max power, and both are receiving max power. Both are in the same vehicle.

What makes the 2000rms substage "louder" SPL wise? The only thing i can think of is the greater force required to move the more beefy subwoofer, but at the same time that confuses me in terms of an SPL meter measuring pressure, if the same amount of air is being moved.

If they are displacing the same volume they will have the same output level.

 

[xtremebassjunky 10+ year member]

there are more variables than displacement i would've thought

 

[mrogowski 5,000+ posts]

Give me a second...