Damping materials for speaker cabinets? - Page 5 - 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 28th March 2003, 02:47 AM   #41
frugal-phile(tm)
diyAudio Moderator
 
planet10's Avatar
 
Join Date: Oct 2001
Location: Victoria, BC, NA, Sol III
Blog Entries: 5
Quote:
Originally posted by TheoM
This is a transmission line right? Stuffing the line makes the line "longer" - retuning it, so I assume you tune that by measurement to the intended frequency. Stuffing = tuning in a t-line.
The latest research shows that this is not true -- that stuffing a line slows down the speed of sound is starting to look like a classical design myth. Stuffing the line does not move the fundemental resonance, it damps the ripple.

dave
__________________
community sites t-linespeakers.org, frugal-horn.com, frugal-phile.com ........ commercial site planet10-HiFi
p10-hifi forum here at diyA
  Reply With Quote
Old 28th March 2003, 02:53 AM   #42
frugal-phile(tm)
diyAudio Moderator
 
planet10's Avatar
 
Join Date: Oct 2001
Location: Victoria, BC, NA, Sol III
Blog Entries: 5
Default Re: Damping in sealed vs ported

Quote:
Originally posted by RobWells
But you also asked about polyfill - isn't this stuffing (rather than damping?)
As determined from the sample you sent me polyfill = BAF wadding

Quote:
Originally posted by TheoM
It impedes airflow - slowing down the air and changing the resonant frequency of the air mass inside the cab while absorbing energy.
This is probably a somewhat inaccurate way of saying it. The damping material converts acoustic energy into heat, and thus makes the box behave as if it were a somewhat larger unfilled box. I doubt that it slows the air down at all -- just reduces its energy.

dave
__________________
community sites t-linespeakers.org, frugal-horn.com, frugal-phile.com ........ commercial site planet10-HiFi
p10-hifi forum here at diyA
  Reply With Quote
Old 28th March 2003, 03:29 AM   #43
TheoM is offline TheoM  United States
diyAudio Member
 
Join Date: Mar 2003
Location: Ohio
Default Design Myth: I buy it

I recently read an authorative sounding article that claimed this but I buy its a design myth. If the stuffing were denser sound would travel faster, not slower, right? Its right up there with Thermal momentum.
  Reply With Quote
Old 28th March 2003, 07:48 AM   #44
frugal-phile(tm)
diyAudio Moderator
 
planet10's Avatar
 
Join Date: Oct 2001
Location: Victoria, BC, NA, Sol III
Blog Entries: 5
Default Re: Design Myth: I buy it

Quote:
Originally posted by TheoM
If the stuffing were denser sound would travel faster, not slower, right?
No, stuffing in the line has close to negligible effect on the speed of sound. Geometry thou can have a profound effect on the resonance footprint of a line.

dave
__________________
community sites t-linespeakers.org, frugal-horn.com, frugal-phile.com ........ commercial site planet10-HiFi
p10-hifi forum here at diyA
  Reply With Quote
Old 28th March 2003, 12:21 PM   #45
7V is offline 7V  United Kingdom
diyAudio Member
 
7V's Avatar
 
Join Date: Feb 2003
Location: North London
Default Re: stuffing or padding?

Quote:
Originally posted by TheoM
Sealed: Stuff it. Kill the backwave. Actually, I'd add a low end damper to the walls like that roofing felt (stuffing does not do well with low end), hanging loosely along the walls, AND stuffing. I've seen high end sealed cabs stuffed to the gills - packed tight. Some people advocate for moderate stuffing which I read as 1/2 full - but I'd fill it up without packing it in, so to speak.
I don't think so Theo. "Kill the backwave" and you kill the speaker.
This is an extremely high end speaker using the best full-range units that money can buy (in my opinion). They're "open back" (conventional) cone drivers which go all the way to over 20kHz. I'm not sure exactly why but experience with my original speaker taught me that too much stuffing deadened the sound.

I'm amazed at how good the new cabinet sounds without any stuffing or padding at all. I will test them using measurement and ears for over stuffing, no stuffing and in between. Ditto with padding. I was just interested to hear other people's formulae for reaching the optimum amount of stuffing and padding (assuming that the cabinet walls are already damped so they don't vibrate significantly and, therefore, bracing is not an issue).

Steve
  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
Adhesive/materials for Constrained Layer Damping Paul W Multi-Way 24 27th October 2008 04:35 AM
Damping TL cabinets? graks Multi-Way 23 22nd April 2005 01:30 PM
Acoustically absorbant materials for cabinets polsol Multi-Way 21 28th August 2004 02:12 PM
speaker without damping materials Kal Multi-Way 4 30th June 2004 10:23 AM
Proac 2.5 Damping materials ? JohnV Multi-Way 2 29th December 2002 11:21 PM


New To Site? Need Help?

All times are GMT. The time now is 07:21 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