Precision devices - Page 10 - diyAudio
Go Back   Home > Forums > Loudspeakers > Subwoofers

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 19th December 2005, 03:29 PM   #91
Geenius is offline Geenius  Netherlands
diyAudio Member
 
Geenius's Avatar
 
Join Date: Jul 2004
Location: near Amsterdam
Why does someone always beat me to it!?
__________________
Tony
  Reply With Quote
Old 19th December 2005, 03:32 PM   #92
diyAudio Member
 
Join Date: May 2002
Location: Switzerland
I didn't invent it myself either !

Regards

Charles
  Reply With Quote
Old 19th December 2005, 03:36 PM   #93
Geenius is offline Geenius  Netherlands
diyAudio Member
 
Geenius's Avatar
 
Join Date: Jul 2004
Location: near Amsterdam
__________________
Tony
  Reply With Quote
Old 19th December 2005, 03:49 PM   #94
Geenius is offline Geenius  Netherlands
diyAudio Member
 
Geenius's Avatar
 
Join Date: Jul 2004
Location: near Amsterdam
Just whipped up a quick drawing:
Attached Images
File Type: jpg serious_sub.jpg (47.9 KB, 431 views)
__________________
Tony
  Reply With Quote
Old 19th December 2005, 03:55 PM   #95
diyAudio Member
 
Join Date: May 2002
Location: Switzerland
The box design looks definitely cool. But you should redesign the guy as he looks a little unimpressed !

Regards

Charles
  Reply With Quote
Old 20th December 2005, 12:08 AM   #96
Retsel is offline Retsel  United States
diyAudio Member
 
Join Date: Jan 2005
Location: Ann Arbor, Michigan
I have a couple more theories why the your particular ripole design contributes toward a more boxy sound. In general I have found that the boxy sound (from any speaker) arises from boxes which are not braced sufficiently. This is really true of horns. I have Hedlund Horns which sounded like a hammer beating a pillow without sufficient bracing. I see several contributing factors to why your boxes may fall into this category.

First, it seems that you are using some sort of MDF. While MDF is great for deadening and thus preventing resonances which otherwise arise from the material, it is not as stiff as other materials. To have a very sharp bass sound, W-dipoles would require very stiff surfaces. To accomplish this with MDF, your various panels would best be doubled in thickness. I built my W-baffle out of 3/4 inch 13 ply birch plywood. This is very stiff stuff. Addiitonally, the baffles on which the drivers are mounted are 1 1/2 inch thick.

My W-dipoles use 18 inch drivers which require smaller panels than your 21 inch drivers which would stress the panels more and allowing them to flex more. I recall that Linkwitz uses 1/2 inch birch with his W-dipoles using 12 inch drivers. I used 3/4 inch for my 18s. Perhaps you should use 1 inch or 1 1/2 inch material.

By cutting holes in your panels, it weakens the panels further from resisting the pressure sources of the drivers.

I did a knuckle rap test. All points of my boxes resonate at frequencies above the crossover point for my drivers which helps to convince me that I would not have cabinet flexure which is too great.

The ripole boxes subjects the panels to greater pressure and are likely to flex more by virtue of their narrower width.

Even considering the points I make here, my boxes still vibrate quite a bit when really pushed with loud bass passages, thus my boxes would benefit further from additional thickness for some panels. I don't think that I would gain too much, but doubling all the 3/4 inch panels in my W-dipoles would likely improve the bass slam a finite amount.

Retsel
  Reply With Quote
Old 20th December 2005, 07:46 AM   #97
Geenius is offline Geenius  Netherlands
diyAudio Member
 
Geenius's Avatar
 
Join Date: Jul 2004
Location: near Amsterdam
Hi Retsel,

Thanks for the input. My enclosures are built from 22mm mdf (1"=25,4mm). I agree that the sturdyness of the boxes could be better. The various boxes are all experimental prototypes and all have the same general "fault" of being not thick enough. I am sure that the boxiness would have been less if I had made them thicker and added some extra bracing, but at least this way I can compare the relative characters.
__________________
Tony
  Reply With Quote
Old 20th December 2005, 09:02 AM   #98
Geenius is offline Geenius  Netherlands
diyAudio Member
 
Geenius's Avatar
 
Join Date: Jul 2004
Location: near Amsterdam
Quote:
Originally posted by phase_accurate



That would make it a cardioid like this one (i.e. case a):

http://www.wvier.de/texte/UniPol.pdf

Regards

Charles
Your wish is my command.........

Click the image to open in full size.
Click the image to open in full size.

Click the image to open in full size.
Click the image to open in full size.

The best of both worlds.
__________________
Tony
  Reply With Quote
Old 20th December 2005, 12:48 PM   #99
wuffer is offline wuffer  Denmark
diyAudio Member
 
Join Date: Feb 2004
Location: denmark
nice sub ... wish it was mine but the woman in the house is saying no but the drives looks very nice

but can i use one of the 12" or 15" with and diy ribbon, crossover around 1khz in a cabinet like the linkwitz orion or something... im not sure what i should go after because my speakers stand in corners
  Reply With Quote
Old 20th December 2005, 01:20 PM   #100
diyAudio Member
 
paulspencer's Avatar
 
Join Date: Sep 2003
Location: Melbourne, Australia
wuffer, you can put an open baffle dipole in a corner as seen in Linkwitz site, but its not so good for the midrange. I've seen a corner dipole woofer under a oris horn which seemed an appropriate combination. Or you could use a sealed monopole 12" for mids and above on top of a corner dipole. 3 way makes sense to me for this kind of setup, with a sub below 40 Hz if desired.
  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
Precision Devices 12" woofers Defo Multi-Way 8 30th July 2009 02:05 AM
Precision devices...... Village Plank Multi-Way 10 14th December 2008 08:49 PM
Precision Devices PD.158 Xmax? buggsson Subwoofers 6 20th May 2008 07:55 AM
Precision Devices tinitus Multi-Way 1 8th January 2008 01:57 AM
Compact 15" sub - BMS or Precision Devices? DIAR Subwoofers 7 4th January 2007 05:06 PM


New To Site? Need Help?

All times are GMT. The time now is 05:29 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