School project, small driver but "big" enclosure - diyAudio
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 29th August 2012, 10:01 PM   #1
diyAudio Member
 
Rullknufs's Avatar
 
Join Date: Mar 2010
Location: Sweden
Send a message via Skype™ to Rullknufs
Default School project, small driver but "big" enclosure

Something like this:
Click the image to open in full size.

The purpose of this is to have something to write about, relating to the physics and math subjects in school. The idea is to use a small driver, like 3-4" and use a big enclosure to amplify the sound and extend the bass.

I don't want to build a 300l cabinet that requires extreme woodworking skills. I'm more looking for something in the picture above. Does not require extreme skills yet it could provide me with lots of things to write about (like pipe resonances and such) and also achieving a good sound.

The budget is maximum 500SEK per driver, that equals ~$75/~60/~47

The finished product is not important as the work and writing, so therefore I'm looking at pretty cheap small drivers.
__________________
My audio and DIY blog: http://phimusic.blogspot.se/
  Reply With Quote
Old 29th August 2012, 10:10 PM   #2
chrisb is offline chrisb  Canada
diyAudio Member
 
Join Date: Aug 2002
Location: victoria BC
Quote:
Originally Posted by Rullknufs View Post
Something like this:
Click the image to open in full size.

The purpose of this is to have something to write about, relating to the physics and math subjects in school. The idea is to use a small driver, like 3-4" and use a big enclosure to amplify the sound and extend the bass.

I don't want to build a 300l cabinet that requires extreme woodworking skills. I'm more looking for something in the picture above. Does not require extreme skills yet it could provide me with lots of things to write about (like pipe resonances and such) and also achieving a good sound.

The budget is maximum 500SEK per driver, that equals ~$75/~60/~47

The finished product is not important as the work and writing, so therefore I'm looking at pretty cheap small drivers.

Fostex FF85WK? - might not necessarily work in the pictured style, but maybe something like the Woden Vampyr?
__________________
now on sabbatical
  Reply With Quote
Old 29th August 2012, 10:13 PM   #3
diyAudio Member
 
Rullknufs's Avatar
 
Join Date: Mar 2010
Location: Sweden
Send a message via Skype™ to Rullknufs
Quote:
Originally Posted by chrisb View Post
Fostex FF85WK? - might not necessarily work in the pictured style, but maybe something like the Woden Vampyr?
Seems a bit complicated to build though, including lots of angles and such.
__________________
My audio and DIY blog: http://phimusic.blogspot.se/
  Reply With Quote
Old 29th August 2012, 10:14 PM   #4
diyAudio Member
 
Kindhornman's Avatar
 
Join Date: Aug 2012
Location: Los Angeles, California
Seems like a simple transmission line project with a cheap speaker if you are just trying to demonstrate the principles here. Would be a fun project in school and some easily cut wood from the wood shop and some glue. Another easy thing is to use round plastic pipe and one 180 degree bend or two 90's and some pipe glue with a flange to mount the driver to the tube.

A second idea, just about as simple is to install the speaker in the middle, actually offset so you have two different length and you have a twin tuned transmission line a la a boss wave radio design. Each length is set to a different frequency and you have two frequencies instead of one emanating from the tube ends.
simple to calculate the tuning frequencies and so it also becomes a math problem for the students to solve.

Last edited by Kindhornman; 29th August 2012 at 10:20 PM.
  Reply With Quote
Old 29th August 2012, 10:18 PM   #5
chrisb is offline chrisb  Canada
diyAudio Member
 
Join Date: Aug 2002
Location: victoria BC
Quote:
Originally Posted by Rullknufs View Post
Seems a bit complicated to build though, including lots of angles and such.
fair enough
__________________
now on sabbatical
  Reply With Quote
Old 29th August 2012, 10:19 PM   #6
diyAudio Member
 
Rullknufs's Avatar
 
Join Date: Mar 2010
Location: Sweden
Send a message via Skype™ to Rullknufs
Quote:
Originally Posted by Kindhornman View Post
Seems like a simple transmission line project with a cheap speaker if you are just trying to demonstrate the principles here. Would be a fun project in school and some easily cut wood from the wood shop and some glue. Another easy thing is to use round plastic pipe and one 180 degree bend or two 90's and some pipe glue with a flange to mount the driver to the tube.
You've got it!

The idea with pipes seem interesting, and would require less woodworking but still provide a good sound, I guess? Is there any limit to how long the pipe can be? I mean, I have no problems making it several meters long but with many bends. I was thinking of setting maximum height to ~180cm just to reduce handling problems
__________________
My audio and DIY blog: http://phimusic.blogspot.se/
  Reply With Quote
Old 29th August 2012, 10:23 PM   #7
diyAudio Member
 
Rullknufs's Avatar
 
Join Date: Mar 2010
Location: Sweden
Send a message via Skype™ to Rullknufs
Quote:
Originally Posted by chrisb View Post
fair enough
Well, it's a school project and since I'm studying nature science the main focus of the project is not the actual construction process. What matters is documentation and researching about what I've done.
__________________
My audio and DIY blog: http://phimusic.blogspot.se/
  Reply With Quote
Old 29th August 2012, 10:28 PM   #8
chrisb is offline chrisb  Canada
diyAudio Member
 
Join Date: Aug 2002
Location: victoria BC
Quote:
Originally Posted by Rullknufs View Post
Well, it's a school project and since I'm studying nature science the main focus of the project is not the actual construction process. What matters is documentation and researching about what I've done.

Good opportunity then to document your study of, and use of formulas and math related to Quarter Wave behaviour*

You could do far worse than to immerse yourself in the work of Martin King, to name only one

*fortunately I "have guys" for that, otherwise the math would get embarrassingly mangled - I'll just stick to slapping together boxes made from other folks' designs
__________________
now on sabbatical
  Reply With Quote
Old 29th August 2012, 10:34 PM   #9
diyAudio Member
 
Rullknufs's Avatar
 
Join Date: Mar 2010
Location: Sweden
Send a message via Skype™ to Rullknufs
Quote:
Originally Posted by chrisb View Post
Good opportunity then to document your study of, and use of formulas and math related to Quarter Wave behaviour*

You could do far worse than to immerse yourself in the work of Martin King, to name only one

*fortunately I "have guys" for that, otherwise the math would get embarrassingly mangled - I'll just stick to slapping together boxes made from other folks' designs
Yes. I just started with wave studies in physics class talking a bit about standing waves, pipe resonances and such and that's the area I want to "dig deeper in" and construct something using the principles of it.
__________________
My audio and DIY blog: http://phimusic.blogspot.se/
  Reply With Quote
Old 29th August 2012, 11:15 PM   #10
Nanook is offline Nanook  Canada
diyAudio Member
 
Nanook's Avatar
 
Join Date: Feb 2004
Location: Chinook Country.Alberta
Default What level of the Physics and mathematics?

How deep into wave mechanics and math are you?

If you have some calculus, the math is not difficult. Look at the Helmholtz resonator and it's equation. It all starts here.

Perhaps the simplest is what I made: a37" straight pipe using a good (but) cheap co-axial. With a proper cross-over, quite capable. TLs, BRs, horns, etc all rely on the Helmholtz equation at some point. These things are ridiculously easy to build, and rely on the same math.

So your efforts will be spent in the documentation aspects of the project and the correspondence of the end result to theoretical performance, just remember that the output will be into "4-pi" space, not "8-pi" space. So the length of the TL should be halved.

MJ King's work (while helpful and of great use to folks concentrating on completed projects and perhaps less theory), would not help you demonstrate your understanding of wave theory. Your time would be better spent developing the math from first principles, and why you might limit the solution to "4-pi" space. This requires that you differentiate between the Physics (where boundary conditions help you limit the solution(s) to those conditions) and Mathematics . Remember that Physics is NOT Mathematics .
__________________
stew -"A sane man in an insane world appears insane."

Last edited by Nanook; 29th August 2012 at 11:20 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
"Small" enclosure for Tannoy 15" andersen09 Multi-Way 36 28th June 2012 07:34 PM
One "big" woofer or four "small"? Audica Multi-Way 106 10th January 2012 05:23 PM
Need 10" (12") driver for 30 ltr enclosure. (1.1 cu.ft) Fasen Subwoofers 2 25th March 2010 04:18 PM
looking for a small 2" or 3" driver with poor bass response space-cake Full Range 3 27th December 2007 02:16 AM
Project "The Drummer"-Flat DIY sub driver ZuMbAiU Subwoofers 0 28th January 2006 11:40 AM


New To Site? Need Help?

All times are GMT. The time now is 08:15 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