simulating variovent with MJK sheets? - 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 24th March 2008, 05:06 PM   #1
Henkjan is offline Henkjan  Netherlands
diyAudio Member
 
Henkjan's Avatar
 
Join Date: Jan 2006
Location: Berkel en Rodenrijs
Default simulating variovent with MJK sheets?

I am designing a pair of speakers (using the FR125) for my 11 year old daughter. since her wish is that they should not be too large (yes, this sh*t starts already at a young age), I thought of making a aperiodically damped (aka variovent, aka controlled leakage, etc) CB. (I first proposed the miniOnkens, but even these were considered too large)

a thought came in my head to use MJK's mathcad sheets for this, using the BR sheet and then "applying" damping material in the port to simulate the variovent.

anyone has ever done this? @MJK: do you expect this to give good results? and related: in your sheets you give 1 lb/ft³ as max damping material density, why's that?
  Reply With Quote
Old 24th March 2008, 06:46 PM   #2
diyAudio Member
 
gurley123's Avatar
 
Join Date: Oct 2007
I'm not sure about simulating aperiodic vents. I've yet to use the mathcad sheets. However, according to the last few posts by Planet 10, many are now perfering the 4.5 liter aperiodic cabs for the FR125. These are a bit smaller than the MiniOnkens.

Maybe she'll like those?
  Reply With Quote
Old 25th March 2008, 07:31 PM   #3
Henkjan is offline Henkjan  Netherlands
diyAudio Member
 
Henkjan's Avatar
 
Join Date: Jan 2006
Location: Berkel en Rodenrijs
that should give a starting point as well as a fall-back position... thanks.

I'll start the design on the speakers in a week or so (want to finish a pair of table-top TLs first) so if anyine can add some thoughts on this, please do so... and if I'm the 1st to try this, I'll report back here about the results
  Reply With Quote
Old 25th March 2008, 07:33 PM   #4
Henkjan is offline Henkjan  Netherlands
diyAudio Member
 
Henkjan's Avatar
 
Join Date: Jan 2006
Location: Berkel en Rodenrijs
Quote:
Originally posted by gurley123
Maybe she'll like those?
the design is more or less agreed apon, it will not be the average sqare box....
  Reply With Quote
Old 25th March 2008, 07:42 PM   #5
diyAudio Member
 
gurley123's Avatar
 
Join Date: Oct 2007
I'm glad it worked out for you.

11 yrs old and already getting a good set of speakers. That's too cool. My little sister is 17 and I don't think she's heard a decent stereo yet (we never lived in the same house, or else she would have.)

I'm toying with the idea of making her a cool little mini system with some cheap fullrangers and a tripath amp. Looks like it could be fun.
  Reply With Quote
Old 25th March 2008, 08:24 PM   #6
Henkjan is offline Henkjan  Netherlands
diyAudio Member
 
Henkjan's Avatar
 
Join Date: Jan 2006
Location: Berkel en Rodenrijs
well, I have to admit it was the special design I have in mind and the FR125's good looks that made here give in (I had been trying to build a pair of decent speakers for her for a long time already, but she's not realy into music yet), but I'm sure she'll appreciate the result when they are ready
  Reply With Quote
Old 26th March 2008, 05:19 AM   #7
maxro is offline maxro  Canada
diyAudio Member
 
maxro's Avatar
 
Join Date: Dec 2004
Location: Survey says: Least happiest city in Canada
Default Re: simulating variovent with MJK sheets?

Quote:
Originally posted by Henkjan

a thought came in my head to use MJK's mathcad sheets for this, using the BR sheet and then "applying" damping material in the port to simulate the variovent.

anyone has ever done this? @MJK: do you expect this to give good results? and related: in your sheets you give 1 lb/ft³ as max damping material density, why's that?
The 'ported box" work sheet allows densities over 1lb/ft3 in the port section. IIRC, Planet10 had mentioned some reservations about using this method for aperiodic simulation, but I think it to be the best solution thus far. I guess the question is: what is the stuffing density of a Variovent?
__________________
"No one likes jazz that much; even the guy playing it had to take drugs." -Bart Simpson
  Reply With Quote
Old 26th March 2008, 08:57 AM   #8
diyAudio Member
 
Scottmoose's Avatar
 
Join Date: Mar 2005
Location: UK
Depends on what's required. You can sim aperiodic well enough using Martin's sheets.
__________________
Community site www.frugal-horn.com Commercial site www.wodendesign.com
  Reply With Quote
Old 26th March 2008, 09:27 PM   #9
Henkjan is offline Henkjan  Netherlands
diyAudio Member
 
Henkjan's Avatar
 
Join Date: Jan 2006
Location: Berkel en Rodenrijs
OK, let's fire up the quattro uh mathcad
  Reply With Quote
Old 26th March 2008, 11:28 PM   #10
diyAudio Member
 
Scottmoose's Avatar
 
Join Date: Mar 2005
Location: UK
You've been watching Ashes to Ashes haven't you?
__________________
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
Modeling a variovent pjpoes Subwoofers 8 18th March 2014 10:52 PM
Simulating MTM,MMT,etc? kyrie48 Multi-Way 5 26th January 2009 11:43 PM
How to calculate an enclosure with variovent ? TomatoBangBang Multi-Way 4 16th January 2009 04:35 PM
Dynaudio Variovent vs. Scan-Speak Vent amichalik Multi-Way 1 11th June 2006 01:42 AM
Variovent placement... arcturus Multi-Way 12 16th October 2004 03:46 AM


New To Site? Need Help?

All times are GMT. The time now is 05:45 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