My sphere in cube idea for reducing standing waves - Page 3 - diyAudio
Go Back   Home > Forums > Loudspeakers > Multi-Way

Multi-Way Conventional loudspeakers with crossovers

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 13th December 2012, 10:48 PM   #21
pepsi is offline pepsi  United Kingdom
diyAudio Member
 
pepsi's Avatar
 
Join Date: Feb 2010
Location: Leicester, England
Quote:
Originally Posted by LineSource View Post
Thanks for the link!
  Reply With Quote
Old 14th December 2012, 12:57 AM   #22
diyAudio Member
 
Join Date: May 2009
Location: New Zealand
Quote:
Originally Posted by pepsi View Post
you cant damp a standing wave because its not moving. you cant hear standing waves. i thought the curved edges of a sphere would 'focus' sound in some way.
  Reply With Quote
Old 14th December 2012, 01:39 AM   #23
diyAudio Member
 
Join Date: May 2010
Location: was Chicago IL, now Long Beach CA
Of course there are nice things about a sphere. For instance, the shape is good at resisting deformation from pressure increases while minimizing material and weight. Anything with flat panels can 'blow up' by flexing, a sphere has to literally expand. So unless it's made of rubber it's a good shape for a pressure container that doesn't propagate sound waves to the outside. And when the wavelengths are long compared to the enclosure the internal shape doesn't matter much.
  Reply With Quote
Old 14th December 2012, 02:06 AM   #24
expert in tautology
diyAudio Member
 
bear's Avatar
 
Join Date: Apr 2002
Location: New York State USA
Well, depending on the way the node is occuring, the sphere could deform out in one or two axis while in on the other, and oscillate like that, no net change in volume, just shape. Could. Think balloon. Just stiffer... or tennis ball when hit, viewed in slow motion.

I suppose that a sphere internally will focus waves hitting the wall, but they won't stop there... they'll be reformed, perhaps with interference and sent back out... resonant nodes can still form.

_-_-bear
__________________
_-_-bear
http://www.bearlabs.com -- Btw, I don't actually know anything, FYI -- [...2SJ74 Toshiba bogus asian parts - beware! ]
  Reply With Quote
Old 14th December 2012, 04:29 AM   #25
diyAudio Member
 
Join Date: May 2010
Location: was Chicago IL, now Long Beach CA
Again, that's only true for higher freque ncies. And such a sphere should be tensioned with internal wires so it doesn't deform.
  Reply With Quote
Old 14th December 2012, 04:36 AM   #26
Einric is offline Einric  United States
diyAudio Member
 
Einric's Avatar
 
Join Date: Feb 2011
Location: Bozeman, MT
I always figured on using a punching balloon, this way you could tailor your volume to your needs.
You could lay up 3/8" worth of fiberglass really easy and leave the balloon in tact as a sort of rubbery inner coating.
You could even pull the balloon at one end to make a teardrop shape if you wanted.
A continual curve layup of fiberglass 3/8" thick would be RIDICULOUSLY strong and light.
A bit itchy though I guess.
  Reply With Quote
Old 14th December 2012, 08:28 PM   #27
pepsi is offline pepsi  United Kingdom
diyAudio Member
 
pepsi's Avatar
 
Join Date: Feb 2010
Location: Leicester, England
Quote:
Originally Posted by bear View Post
Well, depending on the way the node is occuring, the sphere could deform out in one or two axis while in on the other, and oscillate like that, no net change in volume, just shape. Could. Think balloon. Just stiffer... or tennis ball when hit, viewed in slow motion.

I suppose that a sphere internally will focus waves hitting the wall, but they won't stop there... they'll be reformed, perhaps with interference and sent back out... resonant nodes can still form.

_-_-bear
people keeping talking about standing waves being a problem. as far as i undersatnd, internal standing waves (which are waves canceling themselves out) are actually good when inside the enclosure. however, resonant nodes, like you mentioned would be problamatic.
  Reply With Quote
Old 14th December 2012, 08:30 PM   #28
pepsi is offline pepsi  United Kingdom
diyAudio Member
 
pepsi's Avatar
 
Join Date: Feb 2010
Location: Leicester, England
has anyone got access to any comparitive measurements of different internal enclosure shapes?
  Reply With Quote
Old 14th December 2012, 09:13 PM   #29
expert in tautology
diyAudio Member
 
bear's Avatar
 
Join Date: Apr 2002
Location: New York State USA
standing waves will produce resonant nodes and anti nodes by definition... afaik.

wires will vibrate and ring...

if you want a perfect enclosure you have two:

- anechoic chamber
- infinite baffle



_-_-bear
__________________
_-_-bear
http://www.bearlabs.com -- Btw, I don't actually know anything, FYI -- [...2SJ74 Toshiba bogus asian parts - beware! ]
  Reply With Quote
Old 14th December 2012, 10:09 PM   #30
diyAudio Member
 
Join Date: May 2010
Location: was Chicago IL, now Long Beach CA
Standing waves cancel in some spots and reinforce in others, depending on whether you're at a node or anti-node. But indeed, a resonant point can become a 'trap' for that frequency (or a bit lower) when you stuff the space with absobent material. And for low frequencies the shape is irrelevant, it's just an air-spring tank.
  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
Minimising standing waves GerhardW Multi-Way 13 2nd September 2008 07:43 PM
Standing waves, anyone willing to experiment ? jay1st Multi-Way 4 10th February 2008 01:33 AM
Standing waves again... Vikash Multi-Way 4 3rd June 2004 11:25 PM
Golden ratios and standing waves Vikash Multi-Way 36 27th September 2003 02:12 AM
curved enclosures/standing waves RobWells Multi-Way 8 1st August 2003 02:28 AM


New To Site? Need Help?

All times are GMT. The time now is 12:13 PM.


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