Doubling Power - 3 db Increase?

[edzy 10+ year member]

well, I had a 2 - 13 W6's on a 1000 watts and was doing a 139. Threw them on a AQ2200 and did 142. same box, just more amp. I plan on making a new box as soon as the weather breaks, and hope to gain a little more.

Both measured on a TL.

So it was a 3 db gain, but im sure its not a given. Just my case.

 

[sundownz Pro Seller]

Doubling cone area tends to net a 3 dB gain as well assuming you don't have something else limiting you like port compression or a vehicle limitation of some sort (air leak, etc).

I have experienced darn near theoretical 3dB gains in the Jeep several times both doubling cone are and doubling power.

 

[skmfkr 5,000+ posts]

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

that wasnt jacob, it was derrick824, and it was like a 2.2db i believe and from my experience i gained 2.4db from a 1200d to a 2200d

 

[skmfkr 5,000+ posts]

Doubling cone area tends to net a 3 dB gain as well assuming you don't have something else limiting you like port compression or a vehicle limitation of some sort (air leak, etc).
I have experienced darn near theoretical 3dB gains in the Jeep several times both doubling cone are and doubling power.

i went from a 12 to a 15 and gained 4db, 15 to 18 i gained like 1db but it was at a higher freq

 

[roarzorz 10+ year member]

You can look at the testing I just did from one amp to anpther. With a 50% power increase from 1kwatts to 1.5kwatts there was a 1.5db increase. Doubling power from 1kwatts to 2kwatts only showed a 2.3db increase though and from 1.5kwatts to 3kwatts was only a 1.5db increase. Keep in mind that subwoofers have an optimal power band. You can keep shoving more power into them but they're not gonna keep gaining as much. In my bro's truck going from 8kwatts to 16kwatts on his 2 Btl 18s we only saw a 1.5db gain. That's called power compression.

 

[sundownz Pro Seller]

i went from a 12 to a 15 and gained 4db, 15 to 18 i gained like 1db but it was at a higher freq

In the exact same box I was using to test 15s I lost 4 dB going to a 12" driver as well, actually.

In my situation I think I had way too much port area and volume for the 12" driver, though.

It is a bit difficult to compare apples to apples with different sized subs - using multiples of the same size is a bit more apples to apples //content.invisioncic.com/y282845/emoticons/smile.gif.1ebc41e1811405b213edfc4622c41e27.gif

 

[skmfkr 5,000+ posts]

have you gone from a 15 to 18?

and i had a 12 in 2.5cF and a 15 in 4.5cF, the 18 i used was in 6cf and also in 6.5cf

 

[sundownz Pro Seller]

I have not tried an 18" in my box - not enough depth.

 

[Cpyder 10+ year member]

Here it is. Taken from this physics book: Cutnell & Johnson Physics 7th Edition Vol. 1. And, no, I'm not nerd enough to own this book, I'm just in college. It's my roommate's.

Ex. 9 page 491

Audio system 1 produces an intensity level 90 dB and audio system 2 produces an intensity level of 93 db. Determine the ratio of (intensity2 / intensity 1) (Side note: Intensity has a unit of W/m^2. Intensity level has a dimensionless value of dB.)

After all the work, which I'm not typing, they find the ratio is 2. This means means that doubling the intensity changes the loudness by 3db.

There's another example that shows how a 200 Watt system would only sound about double as loud as a 20 Watt system at full volume.

So you need 10X the power to double the loudness.

That's the math. In real life, like most of you stated, there's way more variables.

 

[RAM_Designs 5,000+ posts]

Comparing the change in spl from one power level to another would be better done at levels where there won't be a ton of stress on the sub, causing heat issues/imp rise/altered t/s parameters/power compression. I think if you go from 250 to 500 you'll see a closer correlation to the 3db "rule."

 

[Cpyder 10+ year member]

Comparing the change in spl from one power level to another would be better done at levels where there won't be a ton of stress on the sub, causing heat issues/imp rise/altered t/s parameters/power compression. I think if you go from 250 to 500 you'll see a closer correlation to the 3db "rule."

Very good point too.

 

[Tinted 10+ year member]

most of you guys fail, i have actually tested this many times.

the 3db gain by doubling power is false. doubling power should gain you 1.5 db AND doubling the cone (to propertly distribute and reproduce the added power) should give you another 1.5 db gain. so total is 3 db when u double power and cone.

BUT

this is all speaker dependant. sometimes doubling the power gives you way more than 3 db's and sometimes it gives you less than 1.5 db's. the efficiency of the speaker is key here.

if you have 1 speaker and you double power you proably wont gain 3 db's. if you have 3 of the same speakers and you double the power goin to the 3 speakers you will gain more than 3 db's.

efficiency is key when it comes to this theory.

 

[Xprime4 10+ year member]

most of you guys fail, i have actually tested this many times.
the 3db gain by doubling power is false. doubling power should gain you 1.5 db AND doubling the cone (to propertly distribute and reproduce the added power) should give you another 1.5 db gain. so total is 3 db when u double power and cone.

BUT

this is all speaker dependant. sometimes doubling the power gives you way more than 3 db's and sometimes it gives you less than 1.5 db's. the efficiency of the speaker is key here.

if you have 1 speaker and you double power you proably wont gain 3 db's. if you have 3 of the same speakers and you double the power goin to the 3 speakers you will gain more than 3 db's.

efficiency is key when it comes to this theory.

I hope i'll get a lot more db'z with my 18 Q. The only unblown amp i've got left is a ma audio1889i cheap and overrated alot. I'm not even suppose to put that amp at 1ohm but i'm doing it temp while waiting for my bxi2006d. Do you think i'll get more than 3db gain if i'm gonna give the Q 1500watts + while i'm at around 400-600 watt going to it right now?

Does sound loud at all compare to two type r twelves

It ain't loud at all at around 500 watt but ain't got a lot of excursion ...

 

[Cpyder 10+ year member]

if you have 1 speaker and you double power you proably wont gain 3 db's. if you have 3 of the same speakers and you double the power goin to the 3 speakers you will gain more than 3 db's.

efficiency is key when it comes to this theory.

If you double to each speaker, yeah, but if you just double the total power to all 3 combined, mathematically you'll see 3db.

 

[Tinted 10+ year member]

its hard to tell how much more you would get. as soon as you beggin to feed more power (actual clampped power) to the sub than its rated RMS you begin to loose efficiency in a huge way, at that point you are not going to get a 3 db gain.

like if you have a sub rated for 150 rms watts and if its already getting 150 rms watts, you are not going to gain 3 db's by giving it 500 rms watts.