Go Back   Home > Forums > >
Home Forums Rules Articles diyAudio Store Blogs Gallery Wiki Register Donations FAQ Calendar Search Today's Posts Mark Forums Read

Multi-Way Conventional loudspeakers with crossovers

Acoustics of corners
Acoustics of corners
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 17th January 2018, 01:10 PM   #31
AllenB is offline AllenB  Australia
diyAudio Member
 
Join Date: Oct 2008
I see it as more or less of the same thing, different approach, though I'm willing to be corrected.
  Reply With Quote
Old 17th January 2018, 01:23 PM   #32
scholl is offline scholl  United States
diyAudio Member
 
Join Date: Dec 2012
Quote:
Originally Posted by AllenB View Post
Can. I'm not saying it's easy tracking down issues in the lower midrange, it's probably the most difficult. Very important to good sound as well. That tactile feel and all.

Any idea whether the modes in question are whole room connected or mostly single wall reflections?
I'm going to say whole room. Also it's a stick and drywall room within a concrete room. With concrete floor. Double yuck. I should just repurpose the bad room and utilize an upstairs room by creating good diffusion.
  Reply With Quote
Old 17th January 2018, 01:23 PM   #33
scottjoplin is offline scottjoplin  Wales
diyAudio Member
 
scottjoplin's Avatar
 
Join Date: Dec 2015
Location: Penrhyndeudraeth
Yes, I think in practice it probably is. Theoretically in a perfectly symmetrical room it would mean no room modes. This comes close and is more practical DP_woofer_room
__________________
Woofer Assisted Wideband is the New Testament renounce the anachronistic acronym FAST
  Reply With Quote
Old 17th January 2018, 07:38 PM   #34
gedlee is offline gedlee  United States
diyAudio Member
 
gedlee's Avatar
 
Join Date: Dec 2004
Location: Novi, Michigan
Quote:
Originally Posted by scholl View Post
What is your favorite recipe for a dead wall?

Scott
Hang two sheets of drywall on resilient channel and glue them together with a non-hardening damped glue, i.e. constrained layer damping. They must float so seal the edges with a soft material. (And no shorting screws please! I screw the layers together until the glue dries and then remove them.) These large panels will be great LF absorbers. Also remember that at LFs it is only necessary to dampen on of any two opposing surfaces. One wall acts exactly the same as two walls in the modal region.
__________________
Earl Geddes Gedlee Website
  Reply With Quote
Old 18th January 2018, 07:53 AM   #35
AllenB is offline AllenB  Australia
diyAudio Member
 
Join Date: Oct 2008
Quote:
Originally Posted by scottjoplin View Post
This comes close and is more practical DP_woofer_room
I don't know what this means..
Quote:
Thus, such a configuration should therefore yield bass response which sounds subjectively similar to dipole
..and I don't much go for the idea of dipoles exciting less modes, and even 'if' they did, the goal is the same and why try to avoid what has to be done?
  Reply With Quote
Old 18th January 2018, 10:50 AM   #36
c_door is offline c_door  Italy
diyAudio Member
 
Join Date: Jan 2006
Location: Milano, Italy
Quote:
Originally Posted by gedlee View Post
Hang two sheets of drywall on resilient channel and glue them together with a non-hardening damped glue, i.e. constrained layer damping. They must float so seal the edges with a soft material. (And no shorting screws please! I screw the layers together until the glue dries and then remove them.) These large panels will be great LF absorbers. Also remember that at LFs it is only necessary to dampen on of any two opposing surfaces. One wall acts exactly the same as two walls in the modal region.
Dr.Geddes,
let's say I have this room 24'x16'x10', all concrete and brickwalls.
What is the size of the hanging drywall panels (long wall and short wall) in order to be effective ? Can I hang let's say three panels on a wall to reach the needed area ?
thanks in advance
  Reply With Quote
Old 18th January 2018, 02:25 PM   #37
scottjoplin is offline scottjoplin  Wales
diyAudio Member
 
scottjoplin's Avatar
 
Join Date: Dec 2015
Location: Penrhyndeudraeth
Quote:
Originally Posted by AllenB View Post
I don't know what this means..
I think he's saying it should sound similar because two closed box speakers driven in opposite phase is a dipole.
__________________
Woofer Assisted Wideband is the New Testament renounce the anachronistic acronym FAST
  Reply With Quote
Old 18th January 2018, 02:32 PM   #38
gedlee is offline gedlee  United States
diyAudio Member
 
gedlee's Avatar
 
Join Date: Dec 2004
Location: Novi, Michigan
Quote:
Originally Posted by c_door View Post
Dr.Geddes,
let's say I have this room 24'x16'x10', all concrete and brickwalls.
What is the size of the hanging drywall panels (long wall and short wall) in order to be effective ? Can I hang let's say three panels on a wall to reach the needed area ?
thanks in advance
Obviously the larger the panels the more absorption you are going to get and at an ever lower frequency. How large they are is up to you. An all concrete room with no leakage would need, IMO, at least one of every opposing pair of walls at least 75% covered.
__________________
Earl Geddes Gedlee Website
  Reply With Quote
Old 18th January 2018, 02:36 PM   #39
gedlee is offline gedlee  United States
diyAudio Member
 
gedlee's Avatar
 
Join Date: Dec 2004
Location: Novi, Michigan
Quote:
Originally Posted by scottjoplin View Post
Yes, I think in practice it probably is. Theoretically in a perfectly symmetrical room it would mean no room modes. This comes close and is more practical DP_woofer_room
John's approach is easy and does help the modal situation in a small room, but it is still not optimum. Letting the frequency response and phase of each woofer be a variable will yield better results. However, this technique requires measurements and some sense of what you are doing, but I have described how to do this many times.

And I agree with Allen above when he said that looking at cancelling modes is not the way to approach the problem. You don't want to cancel the mode, you just want to tame it.
__________________
Earl Geddes Gedlee Website

Last edited by gedlee; 18th January 2018 at 02:39 PM.
  Reply With Quote
Old 19th January 2018, 06:06 PM   #40
scottjoplin is offline scottjoplin  Wales
diyAudio Member
 
scottjoplin's Avatar
 
Join Date: Dec 2015
Location: Penrhyndeudraeth
Something I've been wondering about; say you have a balanced sound at your listening position with no serious peaks or nulls, will be effects of modes elsewhere in the room affect the sound in a negative way?
__________________
Woofer Assisted Wideband is the New Testament renounce the anachronistic acronym FAST
  Reply With Quote

Reply


Acoustics of cornersHide 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

Forum Jump

Similar Threads
Thread Thread Starter Forum Replies Last Post
Q acoustics 2020i vs Boston Acoustics A26 rajeshnitk Full Range 0 26th September 2016 04:43 PM
Help on choosing cabinets for corners tilroh Full Range 24 29th June 2013 12:16 PM
No Room Corners Tamaki Full Range 14 25th September 2010 10:29 PM


New To Site? Need Help?

All times are GMT. The time now is 03:25 AM.


Search Engine Optimisation provided by DragonByte SEO (Pro) - vBulletin Mods & Addons Copyright © 2018 DragonByte Technologies Ltd.
Resources saved on this page: MySQL 14.29%
vBulletin Optimisation provided by vB Optimise (Pro) - vBulletin Mods & Addons Copyright © 2018 DragonByte Technologies Ltd.
Copyright ©1999-2018 diyAudio
Wiki