by Ryan from Ohio » Wed Mar 02, 2005 9:19 am
Ever been asked what will be louder?
4- 12" Brand Z subwoofers or 10- 8" Brand D subwoofers?
Well thats take that question and reword it properly:
What will have more POTENTIAL?
Now lets get down to it!
Common sense tells us this much:
12" Brand A has 32 MM xmax one way
12" Brand Z has 12 MM xmam one way
Brand A has more potential...
But what about when it gets strange, trying to compare different sizes/amounts to see what has more potential?
Thats where the Displacement Formula comes in!
The formula uses the SD of the driver and the one way XMAX to figure total air displacement.
Sd = Effective piston radiating area of the driver. Roughly equal to the area of the cone plus 1/3rd of the surround. Measured in CM^2
Here is the formula:
SD (in CM^2) * XMAX (IN CM) * 2 / 1000= Displacement in Liters.
To get MM to CM simply move the decimal to the left 1 place. So 32MM = 3.2CM
Now for an example.
What will have more potential? 8- 8" Resonant Engineering RE series or a single Resonant Engineering 15" SX sub?
RE8
SD 195
Xmax 1.2CM
195*1.2*2/1000= .468 Liters per
.468*8= 3.744 total Liters of Displacement
SX15
SD 810
Xmax 2CM
810*2*2/1000= 3.24 total Liters of Displacement
Now that you have an effective tool to determine what scenario has better potential I wish you luck!
If anyone would like to collaborate on a project involving this let me know!
Ever been asked what will be louder?
4- 12" Brand Z subwoofers or 10- 8" Brand D subwoofers?
Well thats take that question and reword it properly:
What will have more [b]POTENTIAL[/b]?
Now lets get down to it!
Common sense tells us this much:
12" Brand A has 32 MM xmax one way
12" Brand Z has 12 MM xmam one way
Brand A has more potential...
But what about when it gets strange, trying to compare different sizes/amounts to see what has more potential?
Thats where the Displacement Formula comes in!
The formula uses the SD of the driver and the [b]one way XMAX[/b] to figure total air displacement.
[b]Sd = Effective piston radiating area of the driver. Roughly equal to the area of the cone plus 1/3rd of the surround. Measured in CM^2[/b]
Here is the formula:
[i]SD (in CM^2) * XMAX (IN CM) * 2 / 1000= [b]Displacement in Liters.[/b][/i]
To get MM to CM simply move the decimal to the left 1 place. So 32MM = 3.2CM
Now for an example.
What will have more potential? 8- 8" Resonant Engineering RE series or a single Resonant Engineering 15" SX sub?
RE8
SD 195
Xmax 1.2CM
195*1.2*2/1000= .468 Liters per
.468*8= [b]3.744 total Liters of Displacement[/b]
SX15
SD 810
Xmax 2CM
810*2*2/1000= [b]3.24 total Liters of Displacement[/b]
Now that you have an effective tool to determine what scenario has better potential I wish you luck!
If anyone would like to collaborate on a project involving this let me know!