Acousta-stuf UK? - diyAudio
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 7th February 2008, 07:42 AM   #1
diyAudio Member
 
Join Date: Dec 2005
Location: Stony Stratford
Default Acousta-stuf UK?

I am building a quater wavelength mass loaded TL design and am looking for a source of acousta-stuf or similar in the UK. Parts Express in the States do it but is there a UK source?
__________________
Keladrin
  Reply With Quote
Old 7th February 2008, 11:05 AM   #2
diyAudio Member
 
Scottmoose's Avatar
 
Join Date: Mar 2005
Location: UK
You could use hollow-fibre stuffing ripped out of a pillow from the local cheap bedding supplier. Alternatively, lining the cabinet is just as effective in practice -wool carpet underlay is what I use.
__________________
Community site www.frugal-horn.com Commercial site www.wodendesign.com
  Reply With Quote
Old 8th February 2008, 08:58 AM   #3
diyAudio Member
 
Join Date: Dec 2005
Location: Stony Stratford
Hi Scottmoose,

What is Acousta-stuf - is it just polyester then? I have heard it is the best.
__________________
Keladrin
  Reply With Quote
Old 8th February 2008, 10:21 AM   #4
diyAudio Member
 
Scottmoose's Avatar
 
Join Date: Mar 2005
Location: UK
Acousta-stuf is a nylon-polyamide material. It's certainly very good, but frankly, no more or less in this application than plenty of other available materials, most of which are a whole lot cheaper. Remember, all damping in an MLTL is there for is to attenuate unwanted harmonic resonances, and a properly designed enclosure shouldn't need much. All materials have different attenuation characteristics, but this tends to be of greater significance in ~aperiodic TLs, rather than highly resonant QW lines like an MLTL.
__________________
Community site www.frugal-horn.com Commercial site www.wodendesign.com
  Reply With Quote
Old 8th February 2008, 11:52 AM   #5
diyAudio Member
 
vitalstates's Avatar
 
Join Date: Jan 2006
Location: uk
Hi keladrin

have you thought about long haired wool, the original material(Used to be called Dr Baileys wool). I have listened and measured long and hard to both approaches and prefer LHW by a good mile. If you are interested drop me a PM and I will look out the addresses for suppliers, or depending how much you need I think I have about 2kgs left in my stash....This stuff is now hard to come by due to EU regulations having changed......

Scott,
I can't find the reference at the moment, but there is also the question of arresting the wave speed to achieve phase coherence front and back, which I understand is what LHW is best at.

Ed
  Reply With Quote
Old 8th February 2008, 03:46 PM   #6
diyAudio Member
 
Scottmoose's Avatar
 
Join Date: Mar 2005
Location: UK
Not heard that notion before. Sounds like one of Bradbury's ideas though, or something based on it. I can point out, on a related matter, that damping does not slow the speed of sound sufficiently to have an especially dramatic affect on the tuning frequency. And ideally, you don't want it to do anything at all to the fundamental in a properly designed resonant line. AFAIK, LHW's damping functions are, weight for weight, probably the best out there -perfect for an aperiodic line like Bailey's cabinets. But the material shouldn't be a particularly significant issue for QW lines, because they don't need a great deal to damp out the unwanted upper harmonics, which are pretty easy to take down.
__________________
Community site www.frugal-horn.com Commercial site www.wodendesign.com
  Reply With Quote
Old 8th February 2008, 04:00 PM   #7
diyAudio Member
 
Join Date: Dec 2005
Location: Stony Stratford
Hi Scottmoose,

I always fine-tune my cabinets after damping and it does always effect the tuning about 3Hz or so for half fill. You can see the effect of adding the wadding by using a frequency generator and marking the point at which cone excusion is minimum. This is easy to see with a Jordan as you get a definate 'width' of the blur when viewed sideways as it vibrates - just shine a light on it.
__________________
Keladrin
  Reply With Quote
Old 8th February 2008, 04:35 PM   #8
diyAudio Member
 
Scottmoose's Avatar
 
Join Date: Mar 2005
Location: UK
That's exactly why I say it doesn't do anything especially dramatic to the tuning frequency. The usual 2-3Hz you can expect to get in a QW box isn't exactly going to go down in the books as night & day.
__________________
Community site www.frugal-horn.com Commercial site www.wodendesign.com
  Reply With Quote
Old 11th February 2008, 08:22 AM   #9
diyAudio Member
 
Join Date: Dec 2005
Location: Stony Stratford
Agreed, but I would much rather have it - every little helps in speaker design.
__________________
Keladrin
  Reply With Quote
Old 11th February 2008, 02:34 PM   #10
diyAudio Member
 
Scottmoose's Avatar
 
Join Date: Mar 2005
Location: UK
Oh, I'd be the last to disagree, but as I mentioned above, my point is simply that I don't consider 2-3Hz difference in F3 to be especially significant. 5 - 10Hz? Sure.

Either way, IMO, it's better to design a pipe to go to a target frequency from scratch, rather than trying to achieve it with damping materials. If you get another whisker of extension once it's damped down, that's simply a bonus & secondary to the damping's primary objective of flattening the harmonic resonances.
__________________
Community site www.frugal-horn.com Commercial site www.wodendesign.com
  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
WTB: Wool or Acousta-Stuf Jimmy154 Swap Meet 0 23rd August 2008 11:33 PM
Acousta-stuff and box size Chris40 Subwoofers 2 19th December 2006 01:47 PM
Acousta-stuf question Jiggity Subwoofers 6 5th August 2006 07:27 PM
Lowther Acousta info please! tater8 Full Range 4 18th December 2005 01:25 AM
ALL MY STUF PICS!! and ones of me :S 5th element Everything Else 3 23rd January 2004 06:57 PM


New To Site? Need Help?

All times are GMT. The time now is 10:11 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