Foam Core Board Speaker Enclosures? - Page 126 - 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 5th February 2013, 11:57 AM   #1251
ravener is offline ravener  Singapore
diyAudio Member
 
Join Date: Oct 2008
Location: Singapore
I must confess, the bracing slipped my mind.

I do remember spamming a hell lot of glue round the screws and driver to make sure it's tight as a nut.

The rattling is actually coming from the mouth of the horn, particularly the external edge of the curve.

Nah, I'm not going to bother putting a brace in, this prototype is going to be scrapped and I'm going to make a new pair once the festivities is over - I'll be jobless by then(my company couldn't afford to keep me as production is low) - and have plenty of time on my hands to carefully craft things out.

Will take your advice into practice, i'm thinking of narrowing the width of the horn so i can make it longer, glowglass's spiral on the cornu thread gave me some inspiration to work on.
  Reply With Quote
Old 5th February 2013, 12:03 PM   #1252
xrk971 is offline xrk971  United States
diyAudio Member
 
xrk971's Avatar
 
Join Date: Oct 2012
Location: Virginia
Ravener,
It's an easy 30 second job to add a brace or two right at the edge of the mouth - it will help especially since you say that is where it is rattling. No point is scrapping something if it can be easily fixed.
  Reply With Quote
Old 5th February 2013, 12:18 PM   #1253
ravener is offline ravener  Singapore
diyAudio Member
 
Join Date: Oct 2008
Location: Singapore
Well, this is my first attempt at a foam core enclosure, it's meant to be a practice attempt on how to build one, it's quite a rushed job, and the boards are quite shoddily put together I must say. I never thought to keep this one.

Hope you understand where I'm coming from.
  Reply With Quote
Old 5th February 2013, 01:22 PM   #1254
KLBIrd is offline KLBIrd  United States
diyAudio Member
 
KLBIrd's Avatar
 
Join Date: Jan 2009
Location: Lincoln, Missouri
Send a message via Skype™ to KLBIrd
Has anybody looked at the half inch thick 2 X 4 foot acoustical tiles an experimental enclosure material? The are designed to absorb mid and higher frequencies, and can be glued with Tacky Glue or wood glue.
  Reply With Quote
Old 5th February 2013, 01:38 PM   #1255
Speakerholic
diyAudio Moderator
 
Cal Weldon's Avatar
 
Join Date: Jan 2004
Location: Near Vancouver
ravener, too bad to hear about the bass. It may be the horn length is not enough before it gets to the mouth and basically causes cancellation? Or it is more likely that there is leakage and too little bracing and the bass is being lost to resonating the panels?

KLB, that might work for the flat pieces but the whole thing about using the foam is that you can curve some panels. In the past I have used it instead of damping materials not as a panel.
__________________
Next stop: Margaritaville
Some of Cal's stuff | Cal Weldon Consulting
  Reply With Quote
Old 5th February 2013, 02:36 PM   #1256
ravener is offline ravener  Singapore
diyAudio Member
 
Join Date: Oct 2008
Location: Singapore
Cal,

I'm guessing it's the former, the horn/spiral is a mere 17" on it's longest side. I'll be compressing the width of the horn and see if i can make more rounds in the spiral to lengthen it.
  Reply With Quote
Old 5th February 2013, 02:51 PM   #1257
xrk971 is offline xrk971  United States
diyAudio Member
 
xrk971's Avatar
 
Join Date: Oct 2012
Location: Virginia
Quote:
Originally Posted by KLBIrd View Post
Has anybody looked at the half inch thick 2 X 4 foot acoustical tiles an experimental enclosure material? The are designed to absorb mid and higher frequencies, and can be glued with Tacky Glue or wood glue.
I asked this very question not too long ago Yes, I think using it for either one of the facers or both on the Cornu might help. Horst Mueller (@hm) uses it as the actual channel wall material internal to his horns for this very reason - so that he doesn't have to apply felt damping or use stuffing. I wanted to use it because it comes in convenient 2x2 ft sizes and cuts with a utility knife. It is not cheap though when bought new. It may be a bargain (free) if you happen to find a construction site where they are upgrading interiors and throwing out stuff into the dumpster bin.
  Reply With Quote
Old 6th February 2013, 11:30 PM   #1258
BWRX is offline BWRX  United States
diyAudio Moderator Emeritus
 
Join Date: Jan 2005
Location: Pennsylvania
Quote:
Originally Posted by xrk971 View Post
The use of fancy jigs, routers, and cutting channels and grooves is exactly what I was trying to deliberately avoid with this build as that is what kept so many people from trying to build the Cornu in the first place.
Milling a channel in the sides is a great way to ensure perfect placement and should increase the rigidity but it is more difficult and time consuming.

Instead of cutting a channel in the side panels how about just cutting out the area where the wall is supposed to go. That way you can wedge the wall in place, make sure all the joints are sealed from the outside, and can even cover up both sides with a nice clean sheet.

Awesome thread by the way. I've been out of audio stuff for a couple years now but this is making me want to get back into it! I've got some JX92s drivers waiting to be used but they've never been good candidates for small horns.
__________________
Brian
  Reply With Quote
Old 6th February 2013, 11:58 PM   #1259
Speakerholic
diyAudio Moderator
 
Cal Weldon's Avatar
 
Join Date: Jan 2004
Location: Near Vancouver
Holy cow it's Brian! How the dog and be devil are you man?
__________________
Next stop: Margaritaville
Some of Cal's stuff | Cal Weldon Consulting
  Reply With Quote
Old 7th February 2013, 12:19 AM   #1260
xrk971 is offline xrk971  United States
diyAudio Member
 
xrk971's Avatar
 
Join Date: Oct 2012
Location: Virginia
Quote:
Originally Posted by BWRX View Post
Milling a channel in the sides is a great way to ensure perfect placement and should increase the rigidity but it is more difficult and time consuming.

Instead of cutting a channel in the side panels how about just cutting out the area where the wall is supposed to go. That way you can wedge the wall in place, make sure all the joints are sealed from the outside, and can even cover up both sides with a nice clean sheet.

Awesome thread by the way. I've been out of audio stuff for a couple years now but this is making me want to get back into it! I've got some JX92s drivers waiting to be used but they've never been good candidates for small horns.
Bwrx,
I'm not sure what you mean about cutting out the are where the wall goes? You mean a slot? That's how the commercial Cornu is made with a slot on the middle separator panel. Once you make this out of foam you will see how easy it is to bend and hold by hand while the hot melt sets. Really fast and easy. Alignment is pretty good as you work in sections at a time. Welcome on board! I hope you give the jx92's try with the Cornu!
  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
Speaker damping: Foam or expanding foam akunec Multi-Way 4 11th February 2014 01:14 AM
Replace speaker foam with this odd material? flyingsquirrelman Subwoofers 7 25th July 2010 01:32 PM
concrete board for enclosures? alandarkdale Multi-Way 6 31st March 2007 08:35 AM
Foam core construction for subwoofers morbo Subwoofers 19 30th August 2005 08:09 PM
speaker foam dave k Multi-Way 2 24th June 2003 05:05 AM


New To Site? Need Help?

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