Horn & mixed-order XOver. Please criticize! - diyAudio
Go Back   Home > Forums > Loudspeakers > Multi-Way

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 17th December 2009, 12:59 PM   #1
diyAudio Member
 
Join Date: Aug 2006
Location: Copenhagen, Frederiksberg
Default Horn & mixed-order XOver. Please criticize!

Hello folks,

I am crossing an 18Sound 12NMB420 at 800 Hz to a Coral M-100 driver on a 400Hz tractrix horn. The 12" midrange sits in a semi open baffle enclosure (semi-cardoid).

Click the image to open in full size.

Right now they are crossed passively using a 2. order LR topology. As you can see the mid overlaps the Coral quite a lot while the breakup region is still rather pronounced (1.5 to 3 kHz).

1/6 octave smoothing - please ignore everything above 5 kHz as my soundcard exhibits weird low pass behavior above this frequency.
Click the image to open in full size.

What I am proposing is a mixed order crossover: 3. order mid-woofer and 1. order compression driver. Why this topology? Well, I wish to retain the 2. order type central vertical lobe pattern. To me this yields a very constant and seamless sound nicely showcasing what the drivers can do. I listen from 14 feet away (4.5 meters) and the sound is very coherent over a wide sweet spot.

You are all welcome to suggest the pros and cons of mixed order XO in this particular application.

Cheers
Kris
  Reply With Quote
Old 17th December 2009, 05:10 PM   #2
sqlkev is offline sqlkev  United States
diyAudio Member
 
Join Date: Mar 2004
Location: 714
i'm currently testing a midrange horn + woofer myself and getting good results w/ mixed order crossover, (actively though).

Looks like you need to tame down that peak w/ either a notch or a higher order xover. Do you have any simulation tools for this passive project?
  Reply With Quote
Old 17th December 2009, 05:36 PM   #3
diyAudio Member
 
Join Date: Aug 2006
Location: Copenhagen, Frederiksberg
Alas, no I have not. LspCAD would have been nice.
I would do the notch but only as a last resort.

Btw. the two bass-mid curves are with and without stuffing the U shaped baffle. Guess which one is which.
  Reply With Quote
Old 17th December 2009, 06:17 PM   #4
diyAudio Member
 
Michael Chua's Avatar
 
Join Date: Jul 2006
Location: Calais, ME
Are you able to do a summed response with both drivers at 12dB?

Green plot with stuffing.
__________________
AmpsLab.com
  Reply With Quote
Old 17th December 2009, 06:21 PM   #5
Pano is offline Pano  United States
diyAudio Moderator
 
Pano's Avatar
 
Join Date: Oct 2004
Location: Milliways
Blog Entries: 4
Nice looking rig! The mid reminds me of Gary Pimm's mid cardioid. Works well!

At first glance, I'd say you need a lot more underlap. But I can't really see well enough. Do you have your measurement files for each driver? If you also have them in a text format (like FRD) that would be great.

Impedance sweeps will be very handy if you are going to do this passive.

If you have that info, I'd be happy to help. It can take a lot of hours and hand banging to get it right. Another set of eyes can sure help!
__________________
Take the Speaker Voltage Test!
  Reply With Quote
Old 17th December 2009, 06:46 PM   #6
diyAudio Member
 
Join Date: Aug 2006
Location: Copenhagen, Frederiksberg
This is the summed response:

1/6 oct. smoothing
Click the image to open in full size.

*Green plot* is the correct answer.

I have the imp. plot somewhere and will upload them shortly.

CHeers

Last edited by hasselbaink; 17th December 2009 at 06:47 PM. Reason: image
  Reply With Quote
Old 17th December 2009, 06:49 PM   #7
Pano is offline Pano  United States
diyAudio Moderator
 
Pano's Avatar
 
Join Date: Oct 2004
Location: Milliways
Blog Entries: 4
Cool! Do you have the raw FR curves- with no crossover? That would be a big help.
  Reply With Quote
Old 17th December 2009, 06:56 PM   #8
diyAudio Member
 
Join Date: Aug 2006
Location: Copenhagen, Frederiksberg
Default impedance plot

Wish I had the amplitude in a single 1/3 octave smoothed curve.

18Sound mid. in free air.
Click the image to open in full size.

18Sound & Coral M-100 combined
Click the image to open in full size.

All in all a nice plot.
  Reply With Quote
Old 17th December 2009, 07:07 PM   #9
diyAudio Member
 
Join Date: Aug 2006
Location: Copenhagen, Frederiksberg
Default 18Sound 12NMB420 resp.

Quote:
Originally Posted by panomaniac View Post
Cool! Do you have the raw FR curves- with no crossover? That would be a big help.
The response I've measured is virtually a dead ringer for the one on the product sheet here 12NMB420 - High Output MB Neodymium Driver.
  Reply With Quote
Old 17th December 2009, 07:12 PM   #10
diyAudio Member
 
Michael Chua's Avatar
 
Join Date: Jul 2006
Location: Calais, ME
Can you post a plot with only 3 curves.
1) final summed response
2) LP
3) HP

You should be able to see whether there are any issues with the crossover with both at 12dB.
__________________
AmpsLab.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
2nd order LR series xover formulae PeteMcK Multi-Way 30 9th June 2007 07:27 AM
What Xover order is better? caenot Multi-Way 30 23rd March 2006 05:53 AM
!st order series xover between 5"FR and woofer?? johnmark Full Range 1 2nd May 2005 12:40 AM
does lower order xover have any advantages? andy2 Multi-Way 3 20th November 2004 03:57 PM
2nd Order Xover question johninCR Multi-Way 7 10th August 2004 08:15 AM


New To Site? Need Help?

All times are GMT. The time now is 03:09 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