Pendulum movement of open baffle - 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 15th January 2013, 08:22 AM   #1
diyAudio Member
 
Join Date: Sep 2002
Location: Australia
Default Pendulum movement of open baffle

A while back I made a very simple open baffle for my bedroom. It is basically a folded piece of perspex. Sound is very nice.

I never got around to bracing it, so theoretically it will wobble back and forth.

Amongst the many ideas I have floating around at the moment is to do something equally minimalist with a BG RD50.

Obviously with the extra height it will wobble even more. But I've always wondered whether the attempts by some to build super-stiff open baffles are because we still think in box terms and if such a setup actually provides damping of a sort.

So, I'm wondering just how audible this is likely to be. StigErik and others have done hanging dipoles, which will also wobble back and forth.

So, baffle vibration aside, what affect will the slowish back and forth pendulum motion have?

They would go no lower than 200-300.
Attached Images
File Type: jpg image.jpg (97.2 KB, 228 views)

Last edited by sfdoddsy; 15th January 2013 at 08:28 AM.
  Reply With Quote
Old 15th January 2013, 10:03 AM   #2
diyAudio Member
 
StigErik's Avatar
 
Join Date: Feb 2008
The resonant frequency of the pendulum will be lower than 1 Hz. In addition, the moving mass of the cone is a lot lower than the mass of the baffle. The "wobbling" back and forth will be extremely small, and can be completely ignored.
__________________
dipoles dipoles dipoles dipoles dipoles dipoles dipoles dipoles and dipoles
  Reply With Quote
Old 15th January 2013, 12:45 PM   #3
tsiros is offline tsiros  Greece
diyAudio Member
 
tsiros's Avatar
 
Join Date: Jun 2012
Location: Patra, Greece
Send a message via MSN to tsiros Send a message via Skype™ to tsiros
WAF should be through the roof!
  Reply With Quote
Old 15th January 2013, 01:10 PM   #4
diyAudio Member
 
john k...'s Avatar
 
Join Date: Aug 2004
Location: US
The panel will have many resonant mode, just as a room does. Swaying or wobbling is not the issue but rather exciting resonance modes which may be sufficient to be audible.

Movement of the baffle by simple force transmission is generally never an issue because, as Stig pointed out, the relative mass differences between cone and the other mass elements of the structure generally means the acceleration of the structure is insignificant.

the only way to really determine if the baffle is resonating at various frequencies is to test with an accelerometer at different positions on the baffle.
__________________
John k.... Music and Design NaO Dipole Loudspeakers.
  Reply With Quote
Old 16th January 2013, 05:13 PM   #5
tsiros is offline tsiros  Greece
diyAudio Member
 
tsiros's Avatar
 
Join Date: Jun 2012
Location: Patra, Greece
Send a message via MSN to tsiros Send a message via Skype™ to tsiros
i might be able to think of other ways.
  Reply With Quote
Old 17th January 2013, 12:36 PM   #6
diyAudio Member
 
Join Date: Sep 2002
Location: Australia
So why the obsession with clamping the baffle rigidly that one sees in so many designs?
  Reply With Quote
Old 17th January 2013, 02:46 PM   #7
tsiros is offline tsiros  Greece
diyAudio Member
 
tsiros's Avatar
 
Join Date: Jun 2012
Location: Patra, Greece
Send a message via MSN to tsiros Send a message via Skype™ to tsiros
to dampen resonances, i guess?
  Reply With Quote
Old 17th January 2013, 02:58 PM   #8
diyAudio Member
 
Join Date: Aug 2003
Location: Cheltenham
My only experience is with box speakers. When I built my current speakers (roughly 10" wide floorstanders), I didn't fit any internal bracing. The bass was a bit loose, so I decided to fit some internal bracing to see if it would tighten up the bass. It made quite a large difference and I was very pleased with the results.

Saying all that, i'm not sure it would matter at the frequencies your speakers produce.
  Reply With Quote
Old 17th January 2013, 03:18 PM   #9
diyAudio Member
 
john k...'s Avatar
 
Join Date: Aug 2004
Location: US
Quote:
Originally Posted by sfdoddsy View Post
So why the obsession with clamping the baffle rigidly that one sees in so many designs?
Structural reasons. Constant flexing may lead to fatigue and ultimate structural failure. And, as pointed out, structural rigidity can aid in controlling resonances.
__________________
John k.... Music and Design NaO Dipole Loudspeakers.
  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
Does open baffle suffer from baffle step? 454Casull Multi-Way 15 19th May 2012 03:12 PM
Upwards aligned open baffle? ( pop box meets open baffle ) OllBoll Full Range 3 28th March 2011 01:00 AM
Murphy baffle radios [ open baffle ] keithpeter Full Range 10 11th September 2007 07:59 PM
what effect does baffle have on open-baffle system? kappa546 Multi-Way 6 24th January 2006 10:21 PM
Australians- what solid timbers for baffle? (open baffle loudspeaker) tktran Multi-Way 13 29th November 2004 11:09 PM


New To Site? Need Help?

All times are GMT. The time now is 01:30 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