Go Back   Home > Forums > Loudspeakers > Full Range

Please consider donating to help us continue to serve you.

Ads on/off / Custom Title / More PMs / More album space / Advanced printing & mass image saving
Reply
 
Thread Tools Search this Thread
Old 12th March 2013, 09:53 PM   #11
Speakerholic
diyAudio Moderator
 
Cal Weldon's Avatar
 
Join Date: Jan 2004
Location: British Columbia
Quote:
Originally Posted by xrk971 View Post
Why are you averaging the dimensions of each face?
Because the area of a trapezoid is
h(a+b)/2
where:
h=height
a=shorter of the parallel dimensions
b=longer of the parallels
__________________
Next stop: Margaritaville
Some of Cal's stuff | Cal Weldon Consulting
  Reply With Quote
Old 12th March 2013, 09:56 PM   #12
sts9fan is offline sts9fan  United States
diyAudio Member
 
Join Date: Apr 2006
Location: MA
Math
  Reply With Quote
Old 12th March 2013, 09:58 PM   #13
Speakerholic
diyAudio Moderator
 
Cal Weldon's Avatar
 
Join Date: Jan 2004
Location: British Columbia
Sorry, I'm supposed to have forgotten all this by my age.
__________________
Next stop: Margaritaville
Some of Cal's stuff | Cal Weldon Consulting
  Reply With Quote
Old 12th March 2013, 10:08 PM   #14
diyAudio Member
 
Rullknufs's Avatar
 
Join Date: Mar 2010
Location: Sweden
Send a message via Skype™ to Rullknufs
Shouldn't integrals work for this? Or am I wrong?
__________________
My audio and DIY blog: http://phimusic.blogspot.se/
  Reply With Quote
Old 12th March 2013, 10:12 PM   #15
chrisb is offline chrisb  Canada
diyAudio Member
 
Join Date: Aug 2002
Location: victoria BC
for those with simple constant CSA just draw them out in CAD, and use the measure area function, snapping to intersection points, then times height
__________________
you don't really believe everything you think, do you?
community sites t-linespeakers.org, frugal-horn.com commercial site planet10-HiFi
  Reply With Quote
Old 12th March 2013, 10:13 PM   #16
Speakerholic
diyAudio Moderator
 
Cal Weldon's Avatar
 
Join Date: Jan 2004
Location: British Columbia
Ghosts of departed quantities.
__________________
Next stop: Margaritaville
Some of Cal's stuff | Cal Weldon Consulting
  Reply With Quote
Old 12th March 2013, 10:17 PM   #17
frugal-phile(tm)
diyAudio Moderator
 
planet10's Avatar
 
Join Date: Oct 2001
Location: Victoria, BC, NA, Sol III
Blog Entries: 5
Cal & X fighting over the use of the Associative property.

dave
__________________
community sites t-linespeakers.org, frugal-horn.com, frugal-phile.com ........ commercial site planet10-HiFi
p10-hifi forum here at diyA
  Reply With Quote
Old 12th March 2013, 10:23 PM   #18
Speakerholic
diyAudio Moderator
 
Cal Weldon's Avatar
 
Join Date: Jan 2004
Location: British Columbia
Quote:
Originally Posted by planet10 View Post
Cal & X fighting over the use of the Associative property.
Associative property, really?
Quote:
Originally Posted by xrk971 View Post
take the average area of the top and bottom faces and multiply by the height. So it sounds like the base is 6in x 9in = 54in^2 and top is 4in x 7in = 28in^2.
Is that what you get from the dimensions in post 1?
__________________
Next stop: Margaritaville
Some of Cal's stuff | Cal Weldon Consulting
  Reply With Quote
Old 12th March 2013, 10:25 PM   #19
diyAudio Member
 
Kindhornman's Avatar
 
Join Date: Aug 2012
Location: Los Angeles, California
Has everyone actually forgotten there basic geometry? Cal, glad someones brain still works here and you go that right. Why would you have to use a cad program to figure this out? That is like asking what the area of a circle is! Now if we start talking about the sq. rt of -1 I imagine that many would not know the term i, but a simple trapezoid you could look that up on Google in two seconds. How do you do ac circuit work if you don't remember some basic math?
  Reply With Quote
Old 12th March 2013, 10:41 PM   #20
xrk971 is offline xrk971  United States
diyAudio Member
 
xrk971's Avatar
 
Join Date: Oct 2012
Location: Virginia
Quote:
Originally Posted by Cal Weldon View Post
Associative property, really?

Is that what you get from the dimensions in post 1?
I think we are on same thinking. Without a picture I interpreted trapezoid in the vertical dim with top wall and bottom wall being rectangular csa. I think you see this as a trapezoid csa on top and bottom wall of varying area - trapezoid in all dimensions. Not clear what op meant based on words. That's why we have diagrams. We are both right. Depends on interpretation. Heck op did not even give height. My formula of average areas on top and bottom multiplied by height applies to any cross section, round, trap, triangle, etc. As long as same type of cross section top and bottom.

Last edited by xrk971; 12th March 2013 at 10:44 PM.
  Reply With Quote

Reply


Hide this!Advertise here!
Thread Tools Search this Thread
Search this Thread:

Advanced Search

Posting Rules
You may not post new threads
You may not post replies
You may not post attachments
You may not edit your posts

BB code is On
Smilies are On
[IMG] code is On
HTML code is Off
Trackbacks are Off
Pingbacks are Off
Refbacks are Off


Similar Threads
Thread Thread Starter Forum Replies Last Post
box volume for sub thefox Subwoofers 5 29th December 2011 03:25 PM
Parts Express knock-down trapezoid cabinets cyclecamper PA Systems 11 13th December 2011 10:39 PM
Line Array Isosceles Trapezoid Question dc270 Multi-Way 5 3rd February 2006 06:25 AM
Box volume eitanwaks Multi-Way 7 19th April 2005 02:45 AM


New To Site? Need Help?

All times are GMT. The time now is 12:37 AM.


vBulletin Optimisation provided by vB Optimise (Pro) - vBulletin Mods & Addons Copyright © 2014 DragonByte Technologies Ltd.
Copyright 1999-2014 diyAudio

Content Relevant URLs by vBSEO 3.3.2