Foam enclosure behind 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 21st May 2011, 01:16 AM   #1
Defo is offline Defo  Norway
diyAudio Member
 
Join Date: Nov 2008
Default Foam enclosure behind open baffle

Has anyone tried to encase the bass driver on an open baffle speaker in studio type foam to increase low end a bit while still maintaining a "box free" bass sound?

For example mounting a baffle and a high qts driver to something like this:

Click the image to open in full size.
  Reply With Quote
Old 21st May 2011, 07:31 AM   #2
CLS is offline CLS  Taiwan
diyAudio Member
 
Join Date: Jun 2005
Location: Taiwan
I once did similar thing.

I used large felt pad covering whole rear side of OB. The intrinsic character of almost all sound-absorbing materials is low pass. So the rear radiation would be restricted in lower range, thus an asymmetry front to back response along the frequency. Yes the overall in room response would be bass heavy in tonal balance (if all other things being the same).

Once the FR is re-adjusted for reasonably flat for the listening position, then the asymmetry of front-rear responses would sound very different from a 'normal' OB -- to my ears, it's inferior.

It's not the 'box' sound of ordinary boxed speakers, but the changing polar responses from low to high would be a bad thing in overall presentation.

I guess the polar response (off axis behavior) contributes to the beloved OB sounds more than the resonance free (box-less) construction.

What I said above is for wide band OB speaker. If in multi-way modular type speakers, such device can be used to tune to fit specific design goal... (cardioid midrange, for example) If so, that'll be another story....


ps. oh, one last thing. So called "box free" is mainly affecting the midrange (or to midbass at max.). While bass to sub-bass is not a major concern, actually.

Last edited by CLS; 21st May 2011 at 07:35 AM.
  Reply With Quote
Old 21st May 2011, 09:20 AM   #3
diyAudio Member
 
norman bates's Avatar
 
Join Date: Nov 2003
Location: iowa
I liked it. But if you have the room to have the baffles 6' or greater from the front wall, I'd run without it.

But if you have an open backed box, definitely cover the side walls at least.

Norman
  Reply With Quote
Old 21st May 2011, 01:46 PM   #4
JohnL is offline JohnL  United States
diyAudio Member
 
JohnL's Avatar
 
Join Date: Apr 2004
Location: Tampa, FL
I think what you will get is something like what John K did with his cardoid woofers, or like Hartly did with their "boffle". I think you can achive favorable results, you just have to account for what's going on.
  Reply With Quote
Old 21st May 2011, 04:23 PM   #5
Defo is offline Defo  Norway
diyAudio Member
 
Join Date: Nov 2008
Thanks for the replies

Quote:
Originally Posted by CLS View Post
It's not the 'box' sound of ordinary boxed speakers, but the changing polar responses from low to high would be a bad thing in overall presentation.
Isnt this the case with normal boxed speakers in general?

The speaker will be a two-way with this woofer and this wideband, with the latter in a 350 hz JMLC front horn.

Will it be best to keep the back of both the woofer and wideband driver enclosed in foam or just the woofer I wonder?

Unfortunately I don't have the space for wide OB's placed far away from the walls.
  Reply With Quote
Old 22nd May 2011, 12:31 AM   #6
CLS is offline CLS  Taiwan
diyAudio Member
 
Join Date: Jun 2005
Location: Taiwan
With horn on the mid-high, it's worth trying cardioid in your bass section. Do it first, at least. Since it's already 'asymmetric' front/rear on your horn.
  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
Upwards aligned open baffle? ( pop box meets open baffle ) OllBoll Full Range 3 28th March 2011 02:00 AM
open baffle enclosure for FRS Jazzz Full Range 9 27th June 2007 03:41 PM
Foam, thicker foam or Open Cell qguy Subwoofers 4 11th March 2007 08:06 PM
open baffle subwoofer "enclosure" dimensions noodle_snacks Multi-Way 4 18th July 2006 07:51 AM
Australians- what solid timbers for baffle? (open baffle loudspeaker) tktran Multi-Way 13 30th November 2004 12:09 AM


New To Site? Need Help?

All times are GMT. The time now is 06:22 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