Go Back   Home > Forums > >
Home Forums Rules Articles diyAudio Store Blogs Gallery Wiki Register Donations FAQ Calendar Search Today's Posts Mark Forums Read

Multi-Way Conventional loudspeakers with crossovers

Isobaric frequency limits?
Isobaric frequency limits?
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 22nd September 2017, 05:41 AM   #1
Bill poster is offline Bill poster  Thailand
diyAudio Member
 
Bill poster's Avatar
 
Join Date: Jun 2008
Location: Bangkok/London
Default Isobaric frequency limits?

I'm aware that isobaric loading is mainly frowned upon here, but there's one driver id like to try it with, when funds allow, clamshell
Here Satori WO24P-8 Woofer

Several reasons why this driver may suit; it is fairly sensitive, it goes down to 25hz f3, it needs a big cabinet and the basket looks alot nicer than the cone!

Main question is, if front facing with floor gain, where roughly would I need to cross?
  Reply With Quote
Old 22nd September 2017, 07:24 AM   #2
chris661 is offline chris661  United Kingdom
diyAudio Member
 
chris661's Avatar
 
Join Date: Feb 2008
Location: Sheffield
I'd say when the distance between the bottom of the cones is 1/4 wavelength, you'll need to crossover. That's assuming, of course, that the effects of the basket and magnetic structure is negligible.

Chris
  Reply With Quote
Old 22nd September 2017, 07:28 AM   #3
Bill poster is offline Bill poster  Thailand
diyAudio Member
 
Bill poster's Avatar
 
Join Date: Jun 2008
Location: Bangkok/London
Thanks Chris for answering. Would you say a 250 hz crossover is doable?
  Reply With Quote
Old 22nd September 2017, 10:48 AM   #4
chris661 is offline chris661  United Kingdom
diyAudio Member
 
chris661's Avatar
 
Join Date: Feb 2008
Location: Sheffield
I'd expect 250Hz to be fine.

An alternative would be to use isobaric loading, but not in a clamshell arrangement. You could then roll off the inside woofer and let the outer one radiate as high as you like.

Chris
  Reply With Quote
Old 22nd September 2017, 11:12 AM   #5
Bill poster is offline Bill poster  Thailand
diyAudio Member
 
Bill poster's Avatar
 
Join Date: Jun 2008
Location: Bangkok/London
Hey that's interesting, never heard of that approach. Is that something Wilson Benesch or Linn have done?
  Reply With Quote
Old 22nd September 2017, 01:49 PM   #6
Scottmoose is offline Scottmoose  United Kingdom
diyAudio Member
 
Scottmoose's Avatar
 
Join Date: Mar 2005
Location: UK
Yes. That's the configuration used in the Linn Isobarik and Sara. An expensive way of reducing box volume requirements.
__________________
"'That'll do", comes the cry of the perfectionist down the ages.' James May -The Reassembler
www.wodendesign.com Community sites www.frugal-horn.com http://frugal-phile.com/
  Reply With Quote
Old 22nd September 2017, 02:32 PM   #7
Bill poster is offline Bill poster  Thailand
diyAudio Member
 
Bill poster's Avatar
 
Join Date: Jun 2008
Location: Bangkok/London
Terrible sketch but this is kind of how it would be. A 3 way with the clamshell recessed slightly into the cab. I want the baffle to continue down and over the front of the bass driver magnet, with enough of a gap to install the two bass drivers. Then the down firing port would run down the back of the cab. Click the image to open in full size.
  Reply With Quote
Old 22nd September 2017, 09:05 PM   #8
john k... is offline john k...  United States
diyAudio Member
 
john k...'s Avatar
 
Join Date: Aug 2004
Location: US
I've never figured out the drive behind using an isobaric configuration. Sure you get 1/2 the volume for the rear enclosure, plus the volume of the isobaric chamber so it's not really 1/2 the total volume. It is, on the other hand, 3dB less efficient, whether you connect the drivers in series or parallel. makes more sense just to find a driver with the same Fs, Qms, Qes, 1/2 the Vas. You will have truly 1/2 the box volume and the same 3dB lower efficiency.
__________________
John k.... Music and Design NaO dsp Dipole Loudspeakers.
  Reply With Quote
Old 22nd September 2017, 09:51 PM   #9
Ron E is offline Ron E  United States
diyAudio Member
 
Ron E's Avatar
 
Join Date: Jun 2002
Location: USA, MN
Just mount a 10 or 12 on the side...Qtc up to 1 or so for a sealed is fine, and a sealed with Fc ~35 goes a lot deeper than you think. Venting any small box tuned low is problematic. You can get a lot of driver for $400 that will work better in the application.
__________________
Our species needs, and deserves, a citizenry with minds wide awake and a basic understanding of how the world works. --Carl Sagan
Armaments, universal debt, and planned obsolescence--those are the three pillars of Western prosperity. Aldous Huxley
  Reply With Quote
Old 23rd September 2017, 01:00 AM   #10
Bill poster is offline Bill poster  Thailand
diyAudio Member
 
Bill poster's Avatar
 
Join Date: Jun 2008
Location: Bangkok/London
Quote:
Originally Posted by john k... View Post
I've never figured out the drive behind using an isobaric configuration. Sure you get 1/2 the volume for the rear enclosure, plus the volume of the isobaric chamber so it's not really 1/2 the total volume. It is, on the other hand, 3dB less efficient, whether you connect the drivers in series or parallel. makes more sense just to find a driver with the same Fs, Qms, Qes, 1/2 the Vas. You will have truly 1/2 the box volume and the same 3dB lower efficiency.
Pretty sure two in parallel will give the same output but requires more power to do so ie 4 instead of 8 ohm load. Thats what I've read, correct me if wrong
  Reply With Quote

Reply


Isobaric frequency limits?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

Forum Jump

Similar Threads
Thread Thread Starter Forum Replies Last Post
Private message limits jan.didden Forum Problems 33 27th March 2017 07:05 PM
What limits the power? Pentodo Solid State 13 10th September 2013 06:33 PM
Limits of Human Hearing thadman Multi-Way 18 7th October 2009 12:25 AM
limits in transient time metebalci Tubes / Valves 1 12th April 2004 08:57 AM
BZLS PS limits? protos Pass Labs 4 23rd January 2004 03:06 PM


New To Site? Need Help?

All times are GMT. The time now is 02:43 AM.


Search Engine Optimisation provided by DragonByte SEO (Pro) - vBulletin Mods & Addons Copyright © 2019 DragonByte Technologies Ltd.
Resources saved on this page: MySQL 14.29%
vBulletin Optimisation provided by vB Optimise (Pro) - vBulletin Mods & Addons Copyright © 2019 DragonByte Technologies Ltd.
Copyright ©1999-2019 diyAudio
Wiki