A Challenge to Linkwitz-Riley ? - 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 12th March 2006, 04:46 PM   #1
diyAudio Member
 
jackinnj's Avatar
 
Join Date: Apr 2002
Location: Llanddewi Brefi, NJ
Default A Challenge to Linkwitz-Riley ?

Rene Christensen has published "Active All-Pass Crossover Networks with Equal Resistors and Equal Capacitors" in the Journal of the Audio Engineering Society (Jan/Feb 2006) -- better group delay characteristic compared to LR.
  Reply With Quote
Old 12th March 2006, 11:35 PM   #2
diyAudio Member
 
ShinOBIWAN's Avatar
 
Join Date: Feb 2004
Location: UK
Sounds interesting.

Could you post a schematic or any other details if possible.

Thanks
  Reply With Quote
Old 13th March 2006, 02:06 AM   #3
Bose(o) is offline Bose(o)  Canada
diyAudio Member
 
Join Date: Dec 2001
Location: Ottawa, Ontario, Canada
WHOA?!?!? Really? I definitely must have overlooked that issue. If I find it I can scan her in.
__________________
ERTW 4 life!
"the day has 24hours. If that is not enough take the night."-Roemhild
  Reply With Quote
Old 13th March 2006, 02:12 AM   #4
diyAudio Member
 
Join Date: Jan 2004
Location: Toronto, ON, Canada
Quote:
Originally posted by Bose(o)
WHOA?!?!? Really? I definitely must have overlooked that issue. If I find it I can scan her in.
That'd be awesome.
  Reply With Quote
Old 13th March 2006, 08:27 AM   #5
AndrewT is offline AndrewT  Scotland
diyAudio Member
 
Join Date: Jul 2004
Location: Scottish Borders
Hi,
maybe my question is a bit early, but are we talking about a crossover or a phase/time delay circuit?
__________________
regards Andrew T.
  Reply With Quote
Old 13th March 2006, 09:26 AM   #6
diyAudio Member
 
Join Date: May 2002
Location: Switzerland
Quote:
maybe my question is a bit early, but are we talking about a crossover or a phase/time delay circuit?
What's the difference ????

Fun aside:
It is an active crossover that trades slightly improved phase-characteristics against less steep amplitude response.
The initial rolloff rates of the high- and lowpass are quite shallow.

Regards

Charles
  Reply With Quote
Old 13th March 2006, 09:37 AM   #7
AndrewT is offline AndrewT  Scotland
diyAudio Member
 
Join Date: Jul 2004
Location: Scottish Borders
Hi,
an ALL-pass does not operate as a crossover.

It passes all frequencies upto it design roll off which is usually chosen to be beyond your chosen range of use. Further the ALL-pass is a low pass stage.

There's where my question comes from.
__________________
regards Andrew T.
  Reply With Quote
Old 13th March 2006, 10:16 AM   #8
diyAudio Member
 
ShinOBIWAN's Avatar
 
Join Date: Feb 2004
Location: UK
Quote:
Originally posted by AndrewT
Hi,
maybe my question is a bit early, but are we talking about a crossover or a phase/time delay circuit?
There's no such thing as a Linkwitz-Riley all-pass. So you've got me wondering now. The Linkwitz-Riley is a high or low pass filter network.

I guess the clue is the wording of the article "Active All-Pass Crossover Networks"

It is rather confusing to convention wisdom on the subject. All pass says to me; delays and shelves. Whilst crossover networks suggests high, low and bandpass.

Perhaps this is an all pass network that simply is part of a 'crossover' network?
  Reply With Quote
Old 13th March 2006, 10:18 AM   #9
diyAudio Member
 
ShinOBIWAN's Avatar
 
Join Date: Feb 2004
Location: UK
Found a little bit:

Quote:
Active crossover networks can be constructed with all-pass functions and with the additional constraint that resistors and capacitors have the same value. Two such networks are examined: a fourth-order three-way filter and a sixth-order four-way filter. While the transient responses are not perfect, compared to the familiar Linkwitz-Riley configuration, the group delays are significantly smoother for filters of the same order.
From here:

http://www.aes.org/journal/toc/AES-JanFeb2006TOC.cfm

Looks to be a crossover filter from the description.
  Reply With Quote
Old 13th March 2006, 10:56 AM   #10
heater is offline heater  Finland
diyAudio Member
 
Join Date: Jul 2004
Location: Helsinki
All capacitors and resistors the same hey. That's easy, just use the state variable Linkwitz-Riley design as described by the Rane Corporation here http://www.rane.com/pdf/linriley.pdf

Features:

Fewer resistors and caps if you want to make an adjustable crossover.
Less opamps than say the Rod Elliot Linkwitz-Riley.
High and low outputs from a single "stage" that have identical crossover frequencies. Again nice for an adjustable.

I have only just started to think about active crossovers but I don't see what the problem with phase might be with this. High and low outputs are in phase to withing few milli degrees at all frequencies.

So far I have simulated and built the low and mid section as in the attched schematic.
Attached Images
File Type: png state-variable-linkwitz-riley-crossover.png (97.6 KB, 710 views)
__________________
For me the past is not over yet.
  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
Linkwitz-Riley Crossover questions MBrej Solid State 2 15th January 2009 12:19 PM
Linkwitz Riley Filter Implementation Roysyboy Subwoofers 1 19th September 2005 03:40 AM
Group Buy: Linkwitz-Riley 24db/oct xover PCB's substrate Group Buys 21 10th March 2005 11:44 PM
Linkwitz-Riley Cross over question rs1026 Chip Amps 2 27th August 2004 09:15 PM
linkwitz-riley crossover arthur Solid State 0 28th April 2003 10:26 AM


New To Site? Need Help?

All times are GMT. The time now is 08:04 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