Damping material for Mark Audio CHP-70 slim design - diyAudio
Go Back   Home > Forums > Loudspeakers > Multi-Way
Home Forums Rules Articles diyAudio Store Gallery Wiki Blogs Register Donations FAQ Calendar Search Today's Posts Mark Forums Read

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 18th May 2017, 07:52 AM   #1
diyAudio Member
 
Join Date: May 2016
Location: Århus
Default Damping material for Mark Audio CHP-70 slim design

Hi All

I am building the slim design from Mark Audios homepage:
CHP 70 Natural | Markaudio
I am doing the woodwork now, but I was wondering about damping for this enclosure. There is no info in the plans, and I can't seem to find any online either.
I expect that damping should be added to all speaker enclosures (at least standard ones from standard materials) to avoid standing waves and strong reflections, but I am unsure as to how much and where?

I have the "eggshell"-type that I expect to use for the internal walls, and some "loose stuffing" to put inside the enclosure as well.

My questions are:
*How much eggshell type should I use? - i.e. should the eggshell-type be applied to all walls, or just one side of each parallel wall set (e.g. back wall + 1 side wall + top or bottom)?
*Should I also put eggshell-type on the front baffle?
*how much loose stuffing should I add?

I know that it is a "trial and error"-process, but I have no clue as to appropriate amounts - thus I would like to get it in the right ball park from the beginning...

thank you for all your help!

/BR
Jakob
  Reply With Quote
Old 18th May 2017, 08:43 PM   #2
zman01 is offline zman01  Bangladesh
diyAudio Member
 
Join Date: Feb 2011
Location: Dhaka
Jakob,

Are you building a single driver system? Then maybe ask the mods to transfer your thread to the Full-range forum?

On you question on lining internal walls - the cabinet you are planning to build is bass-reflex (BR) cabinet. For BR cabinets, lining the inside cabinet walls with felt material is quite popular among full-range driver enthusiasts, 10-12 mm of wool felt type material should work. This type of felt can be found as wool carpet underlay.

Regarding application it should be on insides of both the side-walls, inside of top, inside of bottom panel, and inside of back panel.
  Reply With Quote
Old 19th May 2017, 12:27 PM   #3
diyAudio Member
 
Join Date: May 2016
Location: Århus
Hi zman01
Thank you for the feedback!

Yes it is a full-range speaker - but as the question pertained to the cabinet I thought I would put it here...can a moderator please move it if it will receive more attention in the full-range forum?

Regarding the felt material, I have already purchased the eggshell-type found here:
https://bekent.dk/hojtalerskum-aeggebakke-mdm-40.html
As it is listed as "suitable for bass reflex type speakers".
But if felt is indeed better I will buy some?
And if I understand you correctly, it should cover all internal surface except the front?

And how about loose stuffing?
I have this:
https://bekent.dk/daempemateriale-polyester-mdm-2.html
Or do I not need any for this cabinet type?

Thank you for any feedback!

BR
Jakob
  Reply With Quote
Old 19th May 2017, 04:44 PM   #4
zman01 is offline zman01  Bangladesh
diyAudio Member
 
Join Date: Feb 2011
Location: Dhaka
Hi Jakob,

Since you have already got the lining materials, then maybe use them first?

Are you making a removable back panel (or front baffle)? If there is a removable panel, it will be possible for you to take out the existing lining and install some other type of material later if you want to.

So you can try with the egg-crate type and then with the polyester lining and hear the difference if any.

Yes, all internal surfaces except the front.
  Reply With Quote
Old 19th May 2017, 04:57 PM   #5
Lojzek is offline Lojzek  Croatia
diyAudio Member
 
Lojzek's Avatar
 
Join Date: Feb 2012
Location: Croatia
Hi Jakob, go to Elliot Sound Products web, and under Articles, Loudspeaker Design, Volume Filling a Reflex Box you will find an article explaining it.
__________________
Mankind is created for eternity.

Last edited by Lojzek; 19th May 2017 at 05:13 PM. Reason: correction
  Reply With Quote
Old 20th May 2017, 12:39 AM   #6
diyAudio Member
 
Join Date: May 2016
Location: Århus
Grr can't post because token expired :-/
I'll make it brief:
Zman: I'm not planning on a removable back/baffle, as it is to much hassle for me (time is at a premium with 3 small kids :-P)
Lojzek: thanks for the link - interesting reading... But the way I read it, they are suggesting I use foam+fibres, which is exactly what I had planned?
Their point on fibre density is also great, but I'm not sure how close to the driver/port I should stuff it?
BR
Jakob
  Reply With Quote
Old 20th May 2017, 01:35 AM   #7
ICG is offline ICG  Germany
diyAudio Member
 
Join Date: Jul 2007
Location: Sound Cloud 9
Quote:
Originally Posted by jakel1984 View Post
Grr can't post because token expired :-/
For that, just copy the reply to the clipboard (works also on a tablet etc.) before sending. If it fails, just hit 'reply' again and paste it. Voilà.

Quote:
Originally Posted by jakel1984 View Post
Lojzek: thanks for the link - interesting reading... But the way I read it, they are suggesting I use foam+fibres, which is exactly what I had planned?
Their point on fibre density is also great, but I'm not sure how close to the driver/port I should stuff it?
The port has to be free, you need to leave out an empty 'sphere' around it. You should leave also space around the driver. If you don't, the damping material around the port eats up a lot of bass. If there's too much mid-crap comming out of the port (not likely at this speaker), put the port on the back of the box.
__________________
Unemployment is not working.
  Reply With Quote
Old 20th May 2017, 07:55 AM   #8
diyAudio Member
 
Join Date: May 2016
Location: Århus
ICG, thanks for the input - that's what I did the second time around. My first reply was just too lengthy to retype :-/

And thanks for the stuffing input, I'm starting to fell ready :-)

BR Jakob
  Reply With Quote
Old 20th May 2017, 10:11 AM   #9
ICG is offline ICG  Germany
diyAudio Member
 
Join Date: Jul 2007
Location: Sound Cloud 9
YW If you run into any problems, just ask.

You don't have to glue on the foam, at small enclosures it usually stays in place on its own if you don't cut it too small. For many enclosures it works great if you cut one sheet to one U-form shape in the inner dimensions of the box. For your CHP 70 slim around ~45cm in length (dimensions minus the thickness (curves/edges make it shorter) and the height of ~28cm. Then top and bottom. That got several advantages, it goes fast, you keep the pieces big for future projects, you can take it out again easily (if you decide it's too much, want another enclosure or use it in another project) and you avoid too many small pieces which could wander around, blocking the port or find a way into the basket of the driver. For the port and terminals it's often enough if you cut a slit in it and stretch it out over them. Still reusable, fast to do with very little effort.

Keep the driver (air movement) and crossover clear, especally the resistors, they will get hot and could melt or burn the damping material.
__________________
Unemployment is not working.
  Reply With Quote
Old 20th May 2017, 10:14 AM   #10
zman01 is offline zman01  Bangladesh
diyAudio Member
 
Join Date: Feb 2011
Location: Dhaka
ICG,

Since it's a project using a single wide-band driver, it is likely that there will be no cross-over circuit. But, nonetheless good advice on keeping it clear.
  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
Mark Audio CHP-70 gen.2 cabinet suggestions type Full Range 40 29th April 2014 02:30 AM
Which design for CHP-70.1 Cooler King Full Range 22 8th December 2012 03:02 PM
Mark Audio CHP 70 Gen2 loninappleton Full Range 16 4th May 2012 07:42 AM
Mark Fenlon's New CHP-70 (note the "P") markaudio Full Range 52 4th November 2011 01:52 PM
CSS EL70 vs Mark Audio CHP-70 bigaudioscotto Full Range 9 5th September 2011 01:10 AM


New To Site? Need Help?

All times are GMT. The time now is 01:39 AM.


vBulletin Optimisation provided by vB Optimise (Pro) - vBulletin Mods & Addons Copyright © 2017 DragonByte Technologies Ltd.
Copyright ©1999-2017 diyAudio

Content Relevant URLs by vBSEO 3.3.2
Wiki