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 3rd January 2013, 04:49 PM   #1011
bjohng is offline bjohng  United States
diyAudio Member
 
Join Date: Aug 2005
This is about as inspiring as any project I can remember on this blog.

Vifa, board, new blades and hot melt on hand. Fantastic instructions available throughout this blog but somehow I missed how to attach the driver.

Info would be appreciated.
__________________
bjohng
  Reply With Quote
Old 3rd January 2013, 05:28 PM   #1012
xrk971 is offline xrk971  United States
diyAudio Member
 
xrk971's Avatar
 
Join Date: Oct 2012
Location: Virginia
Bjohng,
Welcome on board! There are several ways to attach the driver to the rather soft foam core board. The way I do it is to hot melt glue 4 small pieces of wood on the back side (in the driver chamber) where the screws go - say 0.5 in x 0.5 in x 0.25 in thick. Drill a small hole through the foam core at screw locations and then attach driver with wood screws. I think recently, Fenris posted his technique of building a very nice "cage" out of thin plywood that resides inside the driver chamber. But then this defeats the point of not having to use a saw. I used tin snips to cut my wood to size Anyhow, it holds the driver just fine. You may want to seal the interface between the foam core and the driver with something like putty or gasket foam. A tight seal is essential to good sound.
Good luck and keep us posted.

Last edited by xrk971; 3rd January 2013 at 05:32 PM.
  Reply With Quote
Old 3rd January 2013, 05:38 PM   #1013
diyAudio Member
 
Join Date: May 2009
Location: Seattle, WA
After seeing the cardboard fonken in the w5-1611SAF thread, it's a tempting thought to build one out of foam board. I guess it would take three or four sheets laminated together to get the proper thickness. Who's with me??
__________________
Then again, what do I know?
  Reply With Quote
Old 3rd January 2013, 06:59 PM   #1014
xrk971 is offline xrk971  United States
diyAudio Member
 
xrk971's Avatar
 
Join Date: Oct 2012
Location: Virginia
Chaz,
I missed that post - where is the cardboard Fonken? The Fonken needs a pretty stiff box - I am not sure that the foam core would work well here as it is more of a bass reflexish speaker. I am thinking of doing a scaled down Frugel Horn Mk3 out of foam. It can be scaled down to 30 in high to match foam core stock and use a good but cheap 3.5 inch driver. I think the FH3 can be made with 3 sheets of 20x30 inch board each and the sizes scale nicely for a 3.5 in driver (I am thinking TC9FD of course, the Fountek FR85 is also a possibility). It will look pretty cool plus the foam core has a neat trick in that it can be curved. This allows us to make a nice curved flare of the rear horn which increases the horn mouth area and doubles as nice looking built-in stabilization feet for the rather narrow cabinet.

Last edited by xrk971; 3rd January 2013 at 07:04 PM.
  Reply With Quote
Old 3rd January 2013, 08:00 PM   #1015
diyAudio Member
 
Join Date: May 2009
Location: Seattle, WA
This also just came to mind:
desktop TL with 3" driver (with real bass)
__________________
Then again, what do I know?
  Reply With Quote
Old 4th January 2013, 07:08 PM   #1016
bjohng is offline bjohng  United States
diyAudio Member
 
Join Date: Aug 2005
xrk971,

Thanks for input - 2 projects successfully completed!

First was making an end cap for an 18" length of 4" dia pipe to test my ability to cut the foam board, try your attachment detail and burn in the driver. Stuffed with fiberfill and stood it on end on the carpet.

Second was to make an OB top section for my H frame OB. 12" wide with arched top and driver centered. Active x-over at 100Hz.

Cornu next up on my list when I have a better understanding of the stuffing. It seems like a removable face would allow for experimenting with varying amounts of stuffing.

When considering what I have spent over the years on high priced drivers I am even more amazed at my initial listening sessions. Of course it has it's limitations but so do all drivers.

This has certainly brought the fun factor back to our hobby.

Keep the innovation coming.
__________________
bjohng
  Reply With Quote
Old 4th January 2013, 10:15 PM   #1017
xrk971 is offline xrk971  United States
diyAudio Member
 
xrk971's Avatar
 
Join Date: Oct 2012
Location: Virginia
Bjohng,
You are very methodical! I like that. I am glad your experiments have worked out. The little Vifa is an amazing piece of technology for $12. It works as the top end in an OB very well as it is used in Manzanita OB. How do you like the sound in the sealed 4 inch tube? Regarding removable face: tough because a good seal is important. You can cut little windows in the back foam panel to access stuffing adjustment. Reseal windows with foam core piece that was cutout with hot melt. Before sealing hold in place with tape to listen.
  Reply With Quote
Old 5th January 2013, 12:20 AM   #1018
bjohng is offline bjohng  United States
diyAudio Member
 
Join Date: Aug 2005
xrk971,

Thanks for another easy alternative. It will be a couple of weeks before I get to the Cornu.

In the meantime I took full sheets and centered the drivers to use (OB) with my Home theater later tonight. First test was promising. Report to follow.

No attempt was made to calculate optimum volume for closed tube or density of stuffing. It was the first thing that came to hand. The sound - surprisingly well balanced. The closed box warmed the sound up nicely and gave a very credible full range performance.

This is truly an amazing little speaker.
__________________
bjohng
  Reply With Quote
Old 5th January 2013, 01:13 AM   #1019
xrk971 is offline xrk971  United States
diyAudio Member
 
xrk971's Avatar
 
Join Date: Oct 2012
Location: Virginia
Bjohng,
You might want to offset the drivers from the middle for best performance as OB - golden ratio...
Sounds like fun though, I have wondered how the Vifa sounds in sealed cabinet as I have always used in horns and TL's.
  Reply With Quote
Old 5th January 2013, 01:44 PM   #1020
xrk971 is offline xrk971  United States
diyAudio Member
 
xrk971's Avatar
 
Join Date: Oct 2012
Location: Virginia
Default Frugel Foam 3 - new build starting up

I finally had some time to lay out my homage to the FH3 in foam core. I scaled it to 30 in tall and internal cross sections scaled relative to TC9FD driver Sd. This gives cabinet dimensions of 4.5 in wide x 5.0 in deep (internal dims). Terminus height is 1.33 in and I plan to flare the back horn out in a smooth expansion to 12 in wide. This serves to provide built in stabilization feet and gives horn more lateral expansion. It increases final horn's expansion ratio by almost 3x, hopefully this will boost the weak bass from the tiny 3.5 in Vifa. As usual, cutting or scoring the wings on the horn allows a nice smooth compound curve that looks great and will be quite rigid once glued. I just have to find a bit of time to glue now. I sim'd this in HR and got a reasonable frequency response curve showing the low bass peak at 73 Hz. There is a big dip around 125 Hz but that should be filled in by Vifa's natural peak there as fs is 125 Hz.
Attached Images
File Type: jpg Foam-FH3-layout25137105.jpg (115.4 KB, 426 views)
File Type: png FoamFH3866336856.png (8.5 KB, 429 views)

Last edited by xrk971; 5th January 2013 at 02:05 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
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 09:35 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