Concept, Beolab 11 style isobaric sub using Ikea Blanda metal bowls. - diyAudio
Go Back   Home > Forums > Loudspeakers > Subwoofers

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 23rd June 2012, 03:40 PM   #1
diyAudio Member
 
Join Date: Sep 2008
Location: Bristol
Default Concept, Beolab 11 style isobaric sub using Ikea Blanda metal bowls.

Click the image to open in full size.

2x10" drivers running in isobaric configuration, using MiniDSP for crossovers,

Housed in two attached, sealed 36cm Ikea Blanda bowls. A wooden frame would hold a detached granite slab for the bowls to sit on, spikes in-between the ground/wooden frame & granite/metal bowls.

Thoughts?
  Reply With Quote
Old 24th June 2012, 11:02 PM   #2
eXa is offline eXa  Norway
diyAudio Member
 
Join Date: Dec 2006
How do you get it to be isobaric?
  Reply With Quote
Old 24th June 2012, 11:36 PM   #3
NEO Dan is offline NEO Dan  United States
diyAudio Member
 
NEO Dan's Avatar
 
Join Date: Jun 2008
Location: N.E. Ohio
The depiction appears to be of the push push variety with the bowls connected at the bottom. Push push being a force cancellation strategy would not require the granite...
__________________
Regards,
Dan
  Reply With Quote
Old 25th June 2012, 11:52 AM   #4
diyAudio Member
 
Join Date: Sep 2008
Location: Bristol
Yes they would run push pull. If im right in thinking this allows the cabinet size to be half of the recommended size.

My hi fi racks and orb like speakers all sit on granite (kitchen counter savers sm 4 lrg 9) these help to isolate vibrations and give a sturdy base thats cheaper than the oak, really flat and really stable.

For 20 on metal spun bowls, 9 granite, 4 spikes and 6 oak with a small sheet of mdf, 45 +/- I think I could be a great sounding and looking enclosure.

Looking at the peerless xls 10". Any have any idea how to model this?
  Reply With Quote
Old 25th June 2012, 12:16 PM   #5
diyAudio Member
 
Join Date: Sep 2008
Location: Bristol
Ps. This design also only needs two holes cutting in a round piece of mdf. With a good router it could be constructed within a hour or two.
  Reply With Quote
Old 25th June 2012, 12:24 PM   #6
diyAudio Member
 
Join Date: Jun 2012
Quote:
Originally Posted by Studio Au View Post
Yes they would run push pull. If im right in thinking this allows the cabinet size to be half of the recommended size.

My hi fi racks and orb like speakers all sit on granite (kitchen counter savers sm 4 lrg 9) these help to isolate vibrations and give a sturdy base thats cheaper than the oak, really flat and really stable.

For 20 on metal spun bowls, 9 granite, 4 spikes and 6 oak with a small sheet of mdf, 45 +/- I think I could be a great sounding and looking enclosure.

Looking at the peerless xls 10". Any have any idea how to model this?
Maybe you could also consider Scan-Speak 26W/4558T00 in addition to Peerless 10" XXLS/835016. The Scan-Speak has a lower free-air resonance frequency and might achieve lower total Q in a similarly sized enclosure.

http://www.scan-speak.dk/datasheet/pdf/26w-4558t00.pdf
  Reply With Quote
Old 25th June 2012, 01:28 PM   #7
djk is offline djk
diyAudio Member
 
djk's Avatar
 
Join Date: Feb 2001
Location: USA
"If im right in thinking this allows the cabinet size to be half of the recommended size. "

Sorry, that's not isobaric. The drivers will have to work in whatever size the bowels are. I would run them Push-Pull and use a Linkwitz transform.
__________________
Candidates for the Darwin Award should not read this author.
  Reply With Quote
Old 26th June 2012, 03:13 AM   #8
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 djk View Post
I would run them Push-Pull
To be isobarik the drivers need to be couple together driving the same volume (with a small coupling cavity between the 2 drivers (ie 2 drivers act as a single compound driver). I can dig out pictures to illustrate if necessary.

I would go push-push over push-pull (cancelling 2nd order without doing anything about 3rd order creates a non-monotonic series of harmonics). Besides, push-pull probably wouldn't fit this configuration of half-spheres.

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 26th June 2012, 07:53 AM   #9
diyAudio Member
 
Join Date: Sep 2008
Location: Bristol
Ok thanks Dave, let me try and be clear, as my understanding seems to be way off.

My goals were to try and design a sub, using two drivers to cancel/dampen each others forces, making a non-vibrating cabinet (within reason). And I believed that you could use two large drivers running in push-pull our isobaric to allow for a far smaller cabinet than if run normally (or a far bigger driver)

These bowls could be two separate sealed units, however joining them seemed to make more sense, a larger overall volume of air and the rear pressure form each driver canceled or balanced by the opposite movement of the other, as a passive radiator would work.

Click the image to open in full size.

I saw these on the Voodoo thread, and thought they looked amazing, just didn't want to have to cut the metal, and thought this would lead to a more interesting design.

Am I right in thinking my sub would be omnidirectional? As its not got a baffle but is coming from a small slot.

Does anyone know how to model this?
  Reply With Quote
Old 26th June 2012, 08:26 AM   #10
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 Studio Au View Post
Am I right in thinking my sub would be omnidirectional?
All subs are omnidirectional.

Isobarik will halve the volume needed for the same box Q, but one has to account for the overhead of the coupling chamber (or live with a magnet sticking out). A smaller coupling chamber is better.

Click the image to open in full size.

A single pair of drivers in an isobarik cannot be push-push -- well they can, but the complexity & end volume makes the point moot. To do isobarik and push-push you need 4 drivers (top figure).

Click the image to open in full size.

dave
Attached Images
File Type: gif isobarik-configs.gif (18.4 KB, 911 views)
File Type: gif pushpush-pushpull-figures.gif (19.4 KB, 627 views)
__________________
community sites t-linespeakers.org, frugal-horn.com, frugal-phile.com ........ commercial site planet10-HiFi
p10-hifi forum here at diyA
  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
B&O Beolab 11 - how does it work? natumbri Subwoofers 12 20th August 2013 12:37 PM
Beolab 5 clones!!!!! legendaryfrog Multi-Way 72 16th April 2013 12:31 AM
WTB: 4x Ikea BLANDA bowls, 8" or 12" Spasticteapot Swap Meet 7 11th March 2010 05:46 AM
Ikea Bowls question joe58 Full Range 2 27th February 2010 05:11 PM


New To Site? Need Help?

All times are GMT. The time now is 03:57 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