sub-FATHER

11-26-2009, 02:18 PM

Ok, so how many people actually "know" how to properly calculate enclosure volume???

WITHOUT A CALCULATOR, OR PROGRAM THAT DOES IT FOR YOU!!!!

WITHOUT A CALCULATOR, OR PROGRAM THAT DOES IT FOR YOU!!!!

View Full Version : calculating enclosure volume???

sub-FATHER

11-26-2009, 02:18 PM

Ok, so how many people actually "know" how to properly calculate enclosure volume???

WITHOUT A CALCULATOR, OR PROGRAM THAT DOES IT FOR YOU!!!!

WITHOUT A CALCULATOR, OR PROGRAM THAT DOES IT FOR YOU!!!!

JimJ

11-26-2009, 02:39 PM

I feel like I'm missing the joke...

sub-FATHER

11-26-2009, 02:49 PM

I feel like I'm missing the joke...

theres no joke, just a simple question. who knows the mathmatical equations without useing a program to do it for you. just a general question for the box design section...

you cant allways have the computer next to you. so when your stuck without one who would be lost and who would know the formulas.

i know i do...

theres no joke, just a simple question. who knows the mathmatical equations without useing a program to do it for you. just a general question for the box design section...

you cant allways have the computer next to you. so when your stuck without one who would be lost and who would know the formulas.

i know i do...

QuantumAudio

11-26-2009, 03:07 PM

you want a cookie?? who cares if you know the formulas, theres easy free and quicker calc on the net

I can do simple volume and displacements, but port length baffles me

I can do simple volume and displacements, but port length baffles me

JimJ

11-26-2009, 03:09 PM

you cant allways have the computer next to you.

That's what a copy of the Loudspeaker Designer's Cookbook is for.

That's what a copy of the Loudspeaker Designer's Cookbook is for.

fasfocus00

11-26-2009, 04:00 PM

Try learning geometry retard

WrenchGuy

11-26-2009, 04:04 PM

1728

http://i201.photobucket.com/albums/aa135/WrenchGuy420/formular.jpg

http://i201.photobucket.com/albums/aa135/WrenchGuy420/formular.jpg

marcotheclepto

11-26-2009, 05:48 PM

(L-2xthickness) (w-2x thickness) (D-2xthickness)...? then any other variables are take out... port bracing 45s sub...

manny1337

11-26-2009, 05:55 PM

wxhxl divided by 1728

marcotheclepto

11-26-2009, 05:57 PM

1728

http://i201.photobucket.com/albums/aa135/WrenchGuy420/formular.jpg

wxhxl divided by 1728

:( i forgot the division... lol

http://i201.photobucket.com/albums/aa135/WrenchGuy420/formular.jpg

wxhxl divided by 1728

:( i forgot the division... lol

sub-FATHER

11-26-2009, 11:40 PM

its good to know, i've had to use it many times when i was in the garage!

now wheres my brownie???

now wheres my brownie???

phemps

11-26-2009, 11:42 PM

i always use the manual formulas its not that hard. basic fuckin math

sub-FATHER

11-26-2009, 11:45 PM

i always use the manual formulas its not that hard. basic fuckin math

this will be a short reply section, because most wouldnt know what to do with the formulas! and math is done by calculators and the writen aspect of it is getting lost.

this will be a short reply section, because most wouldnt know what to do with the formulas! and math is done by calculators and the writen aspect of it is getting lost.

ciaonzo

11-26-2009, 11:49 PM

Show us the formula for finding the sealed volume to achieve a target Qtc.

NoCoSPL

11-27-2009, 01:40 PM

Wow. . . OP ur so smart ;)

boogeyman

11-27-2009, 02:59 PM

here ya go ciaonzo........sealed volume to achieve a target Qtc

You may substitute any Qtc between 0.50 and 1.50 in place of 0.70 in both equations (both must have same value) to experiment with enclosure size. Qtc of 0.70 is generally considered an optimum alignment, with very good transient response, low cut-off frequency, and flattest response to the cut-off - See Qtc.

Note: You must always choose a Qtc higher than the driver's Qts!

Find alpha: X = (0.70 / Qts)^2 - 1

Then calculate enclosure volume: Vb = Vas / X

System resonant frequency: Fcb = 0.70 / Qts ( Fs)

To find the theoretical cut-off frequency, use the following chart to find the F3 factor:

Qtc

F3 Factor

Qtc

F3 Factor

0.50

= 1.55

1.00

= 0.79

0.60

= 1.21

1.10

= 0.76

0.70

= 1.0

1.20

= 0.74

0.80

= 0.9

1.30

= 0.72

0.90

= 0.83

1.40

= 0.71

Then: F3 = Fc x (F3 Factor)

You may substitute any Qtc between 0.50 and 1.50 in place of 0.70 in both equations (both must have same value) to experiment with enclosure size. Qtc of 0.70 is generally considered an optimum alignment, with very good transient response, low cut-off frequency, and flattest response to the cut-off - See Qtc.

Note: You must always choose a Qtc higher than the driver's Qts!

Find alpha: X = (0.70 / Qts)^2 - 1

Then calculate enclosure volume: Vb = Vas / X

System resonant frequency: Fcb = 0.70 / Qts ( Fs)

To find the theoretical cut-off frequency, use the following chart to find the F3 factor:

Qtc

F3 Factor

Qtc

F3 Factor

0.50

= 1.55

1.00

= 0.79

0.60

= 1.21

1.10

= 0.76

0.70

= 1.0

1.20

= 0.74

0.80

= 0.9

1.30

= 0.72

0.90

= 0.83

1.40

= 0.71

Then: F3 = Fc x (F3 Factor)

ciaonzo

11-27-2009, 03:14 PM

LOL, thanks boogeyman. I already know it well but I wanted to see if the OP could expand past HxWxL=in^3/1728 for finding volume. I was hoping he would come back at me with the simple Vb = Vas / (( Qtc / Qts ) ² - 1) but he chose not to respond. I certainly do appreciate you taking the time to type all that out and it comforts me to know that some people are using the math once in a while. :)

CRXBMPN

11-27-2009, 03:17 PM

That's what a copy of the Loudspeaker Designer's Cookbook is for.

i've got this book, best $30 I spent :-D (besides that lap dance :confused:) j/k

i've got this book, best $30 I spent :-D (besides that lap dance :confused:) j/k

boogeyman

11-27-2009, 03:20 PM

no problem....Im old-school........thats how we did it before the internet.