Cone area calculator

[spencer321 10+ year member]

Wrong.
Depth does not create more surface area. Sd will be the same regardless of cone geometry. The shape of the cone will not affect the swept volume as the shape of the cone is static throughout the motion of the subwoofer. So a deeper cone doesn't "add" anything.

Even then, the formula for cone area is not simply Pi*r^2 (using the diameter of the driver itself for "r")

//content.invisioncic.com/y282845/emoticons/laugh.gif.48439b2acf2cfca21620f01e7f77d1e4.gif

Where in the hell did you hear that //content.invisioncic.com/y282845/emoticons/confused.gif.e820e0216602db4765798ac39d28caa9.gif

Per Vance Dickason in The Loudspeaker Design Cookbook;

Sd = (3.1416 * D^2)/4

Where D is the diameter of the cone (not diameter of the driver itself) plus one third of the surround at both ends of the measurement (though some companies use 1/2 of the surround).

You all fail.

well that is incorrect, if you measure the diameter of the cone and use that formula *which is pi R^2 unsimplified i might at*, you get the area of a FLAT circle that has the radius of the cone itself, which if you took that same driver and flattened the cone, you would have to cut one side and you would notice a BIG gap missing.

just so ya know D^2/4 IS simply R^2

the CORRECT formula for the surface area of a CONE is as follows

http://www.uwm.edu/~ericskey/TANOTES/Geometry/node15.html

and depth DOES add more surface area...your trying to tell me a circle with a 10" diameter and a cone with a 10" diameter have the same surface area? you my friend fail

 

[audioholic 5,000+ posts]

well that is incorrect, if you measure the diameter of the cone and use that formula *which is pi R^2 unsimplified i might at*, you get the area of a FLAT circle that has the radius of the cone itself, which if you took that same driver and flattened the cone, you would have to cut one side and you would notice a BIG gap missing.
just so ya know D^2/4 IS simply R^2

the CORRECT formula for the surface area of a CONE is as follows

http://www.uwm.edu/~ericskey/TANOTES/Geometry/node15.html

and depth DOES add more surface area...your trying to tell me a circle with a 10" diameter and a cone with a 10" diameter have the same surface area? you my friend fail

Nice try. You would have made a good customer for Xtant a few years ago when they tried selling 'deep coned' subs for 'added cone area'.
A speaker cone moves back and forth in 3-dimensional space, creating a cylindrical shape of used air. This is the speakers potential air displacement. Increasing the DIAMETER of the cone would increase this cylinder, increasing the cone AREA of the cone without changing the diameter will NOT affect the area displaced by this cone. Hence cone depth does not affect a speaker's potential for output in any way what so ever. None. Period.

And Id lose the sarcasm until you are at least posing a correct argument. Probably not even then.

 

[spencer321 10+ year member]

Nice try. You would have made a good customer for Xtant a few years ago when they tried selling 'deep coned' subs for 'added cone area'.
A speaker cone moves back and forth in 3-dimensional space, creating a cylindrical shape of used air. This is the speakers potential air displacement. Increasing the DIAMETER of the cone would increase this cylinder, increasing the cone AREA of the cone without changing the diameter will NOT affect the area displaced by this cone. Hence cone depth does not affect a speaker's potential for output in any way what so ever. None. Period.

And Id lose the sarcasm until you are at least posing a correct argument. Probably not even then.

you are wrong, volume can be explained as surface area multiplied by the distance moved... a flat circle with a diameter of 10 inches that moves one inch with NOT displace as much air as a cone with a diameter of 10 inches that moves one inch.

this is basic geometry

if i have to draw a picture for you, i will be glad to.

and i would loose the aura of all knowing if you don't understand basic geometry, probably not even then

 

[mrogowski 5,000+ posts]

It's a bit more complex than simply measuring it that way Spencer. While your calculations make sense, when it comes to loudspeaker output, there are multitudes of cancellations involved when dealing with a round loudspeaker cone of common shape. So much so, that the general acceptance to it all is to simply ignore the third dimension altogether.

 

[spencer321 10+ year member]

heres a pretty picture for you, 2 surfaces identical in length one has depth the other does not, think of it like a cutout of the center of a cone.

both moved in a linear pattern the same distance... which one looks like it has more volume to you?

 

[mrogowski 5,000+ posts]

Hmmm... Do you know why the typical loudspeaker cone shape is the way it is?

 

[DDeitz 10+ year member]

i think ill pull a chair up and watch someone eat crow

 

[spencer321 10+ year member]

It's a bit more complex than simply measuring it that way Spencer. While your calculations make sense, when it comes to loudspeaker output, there are multitudes of cancellations involved when dealing with a round loudspeaker cone of common shape. So much so, that the general acceptance to it all is to simply ignore the third dimension altogether.

thank you an intelligent response, im not saying that just because its cone it has more output, but the original content was about surface area and i was simply correctly the theory that Pi*r^2 is correct for a cone. then a couple people decided to tell me that the air moved is not affected by the depth of the cone when we are talking about volume, volume is simply whatever something displaces in its path and a cone (because it has more surface area than a circle of equal diameter) displaces more in its short path than a flat circle does, so depth DOES matter as far as STRICTLY volume is concerned, now i don't have a audio or a fluid or thermal dynamics major, im a mechanical engineering technician, but i did have to pass basic geometry for that.

 

[spencer321 10+ year member]

Hmmm... Do you know why the typical loudspeaker cone shape is the way it is?

honestly no, my "guess" would have something to do with the the fact that the cone has to be rigid and light weight and a flat paper cone would have no rigidness at all. but my guess is there is more to it than that, im simply proving a point about the geometry behind a cone and a circle

 

[Rashaddd 5,000+ posts]

if cone depth matters, why don't companies capitalize on it...? Why don't people notice any trend that correlates cone depth with output? Why do most companies have a dust cap that pokes OUT? because cone depth is irrelevant.

Why don't companies make dome shaped speakers? that would really maximize on cone area

 

[mrogowski 5,000+ posts]

You got it - it's all about cone strength. Downside to increasing the depth is increasing the cancellations, and if you get deep enough, you actually end up with less output from the driver compared to one that is more shallow.

If you can find Polar responses of deep cone drivers you will see the effect. On-axis response becomes nullified while off axis response increases.

 

[spencer321 10+ year member]

if cone depth matters, why don't companies capitalize on it...? Why don't people notice any trend that correlates cone depth with output? Why do most companies have a dust cap that pokes OUT? because cone depth is irrelevant.
Why don't companies make dome shaped speakers? that would really maximize on cone area

um there are plenty of companies that make dome shaped speakers, they are just normally midranges and i already answered your question. furthermore the dustcap does not always poke out and when it does it IS a dome so thank you for already explaining how a dome displaces more air than a cone now i don't have to.

think about the physicaly limitations for just a minute before you go running your mouth.

a deeper cone means a deeper mounting depth and a complete restructure of the driver itself.

why is everyone making a big deal out of this... its SCIENCE a cone displaces more air than a flat circle at a given diameter and distance traveled... END OF STORY, i said NOTHING about how that actually relates to sound OR output

 

[spencer321 10+ year member]

You got it - it's all about cone strength. Downside to increasing the depth is increasing the cancellations, and if you get deep enough, you actually end up with less output from the driver compared to one that is more shallow.
If you can find Polar responses of deep cone drivers you will see the effect. On-axis response becomes nullified while off axis response increases.

i learned something.... everyone else should try it!

 

[spencer321 10+ year member]

hey rashaddd... look what i found!

http://people.cornell.edu/pages/peh1/D76%20outside%20of%20box.jpg

its a dome holy crap!!

and btw if you had a "dome" subwoofer the cone would stick out between 1/4 and 1/2 the diameter of the sphere(also known as a perfectly round ball for the geometry impared), so a 15" driver would stick out between 4 and 7.5 inches... smartass

 

[mrogowski 5,000+ posts]

um there are plenty of companies that make dome shaped speakers, they are just normally midranges and i already answered your question. furthermore the dustcap does not always poke out and when it does it IS a dome so thank you for already explaining how a dome displaces more air than a cone now i don't have to.
think about the physicaly limitations for just a minute before you go running your mouth.

a deeper cone means a deeper mounting depth and a complete restructure of the driver itself.

why is everyone making a big deal out of this... its SCIENCE a cone displaces more air than a flat circle at a given diameter and distance traveled... END OF STORY, i said NOTHING about how that actually relates to sound OR output

Looking at it from a raw basic air displacement perspective, you are correct. It will 'produce' more air than a flat diaphragm. What they don't tell you however is that much of the produced air inside the cone simply swirls around randomly, and does not add to the overall displacement of the cone itself. So even though it is producing more displacement, the net result compare to a flat diaphragm is about the same.

Hope this makes sense...