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

Going beyond Fourth order...
Going beyond Fourth order...
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 31st July 2020, 02:53 PM   #51
phase_accurate is offline phase_accurate
diyAudio Member
 
Join Date: May 2002
Location: Switzerland
Quote:
FIR fails this once you get off-axis (as will any electrical filter).
But it does at least achieve it on axis where it has the most effect. Others don't achieve it on any axis at all exactly like you have stated.

Regards

Charles
  Reply With Quote
Old 31st July 2020, 03:53 PM   #52
mark100 is offline mark100  United States
diyAudio Member
 
Join Date: Dec 2010
Going beyond Fourth order...
Quote:
Originally Posted by AllenB View Post
Mark, my point wasn't that shallow or steep is better. It's that two devices, which themselves are imperfect, can work together to create a more desirable system directivity, notwithstanding but including their non-coincidence based interaction. The result being entirely system dependent.

I don't identify with Linkwitz-Riley or any basic filter types. I use what works and complementary is no problem. My DSP has plenty of options, but passive has no such limits.
No, FIR fails once you get off-axis (as will any electrical filter).
I get all that Allen...and i applaud the folks who are willing to juggle all kinds of variables to find the best combination for their purposes.
Me, I'll continue stick to and recommend relatively simple straightforward techniques that use steep complementary linear phase xovers.
I believe if nothing else, the measurements I've posted from various builds speak for the techniques.



BTW, where did you pull the second quote from????
This one...you can create a filter with perfectly flat group delay everywhere
  Reply With Quote
Old 31st July 2020, 04:00 PM   #53
scottjoplin is offline scottjoplin  Wales
diyAudio Member
 
scottjoplin's Avatar
 
Join Date: Dec 2015
Location: Penrhyndeudraeth
Yes, you've posted measurements, in another thread, which you "believe" prove your point when in actual fact they do the exact opposite. I applaud your self-belief, but I find your arguments totally random at times.
  Reply With Quote
Old 31st July 2020, 04:00 PM   #54
mark100 is offline mark100  United States
diyAudio Member
 
Join Date: Dec 2010
Going beyond Fourth order...
Quote:
Originally Posted by phase_accurate View Post
LR is just a special case of in-phase allpass crossover. They are derived by subtracting the output of two equal cascaded highpass or lowpass filters from the output of a single allpass of same order and poles like the aforementioned filter. Only if Butterworth parameters are used the final filter slopes are symmetrical. All other cases are asymmetrical but always sum flat and they are always in phase synchronity. But the LR case has the best lobing behaviour. But the other ones can still be interesting depending on the use case. If you use two 2nd order Bessel lowpass filters and one 2nd order allpass you end up with a crossover that is 4th order lowpass but only 2nd order highpass. The advantage is lower group-delay distortion than LR. One can of course use two Bessel 2nd order highpass filters and a Bessel allpass and end up with a 4th order highpass with second order lowpass crossover. The crossover is always at -6dB. Therefore different pole frequencies have to be used for the same crossover frequency for either of the asymmetrical cases. If it weren't that hot at the Moment there would be more details that could pop up but maybe later on .

Regards

Charles
Thank Charles, i get some of what you say, but most is beyond.
I do like to run transfers of various IIR xover / filter implementations, and study papers like the Rane Notes..... but mostly just out of curiosity ...
Very cool, the knowledge you guys amassed re IIR and passive.
  Reply With Quote
Old 1st August 2020, 05:04 AM   #55
AllenB is offline AllenB  Australia
diyAudio Moderator
 
AllenB's Avatar
 
Join Date: Oct 2008
Going beyond Fourth order...
Quote:
Originally Posted by mark100 View Post
I believe if nothing else, the measurements I've posted from various builds speak for the techniques.
An understanding of a standalone phenomena is a very helpful thing. People search long and hard for such information. If you can identify the aspects of your horns that demonstrate the effect in isolation, that's a good thing. Then it can be considered in any design as one of the requisite sliding compromises.

On the other hand adding that it is invariably a fix, is hyperbole. Not saying that it isn't can also be misleading. Nutting out these inconsistencies and ambiguities is an aspect of peer review. Where does the buck stop?
Quote:
BTW, where did you pull the second quote from????
This one...you can create a filter with perfectly flat group delay everywhere
Post#19 by CharlieLaub
  Reply With Quote
Old 1st August 2020, 02:48 PM   #56
mark100 is offline mark100  United States
diyAudio Member
 
Join Date: Dec 2010
Going beyond Fourth order...
Quote:
Originally Posted by AllenB View Post
An understanding of a standalone phenomena is a very helpful thing. People search long and hard for such information. If you can identify the aspects of your horns that demonstrate the effect in isolation, that's a good thing. Then it can be considered in any design as one of the requisite sliding compromises.

On the other hand adding that it is invariably a fix, is hyperbole. Not saying that it isn't can also be misleading. Nutting out these inconsistencies and ambiguities is an aspect of peer review. Where does the buck stop?
Post#19 by CharlieLaub
Ok, fine. I can accept all that.

Other than i would ask when you quote and name one person in a post, that when you pull additional quotes from additional people, you also name the source along with those quotes.

I will try to carefully document any effect in isolation before over describing its effect as invariable. Or just simply state, that so far I keep getting these results with this effect.
That should prune the 'hyperbole' to which you object.



And to hold both of us to the same standard.....

A few of your quotes from this thread:

"OK, here's a starting point for LR96, uF and uH, the impedance stays above 8 ohms."

"I don't identify with Linkwitz-Riley or any basic filter types. I use what works and complementary is no problem. My DSP has plenty of options, but passive has no such limits."

When you say passive has no such limits vs DSP's plenty of options...
....and when much of the thread has referred to the unique ability of linear phase xovers to provide both steep xover and flat phase....
.... and when i asked what was the phase was that LR96 you were building and i received "Just what you'd expect it to be"

Well, i expect it to have completely butt ugly unusable phase rotation and group delay.
To the point i think it's pretense to even propose a passive LR16 as viable, other than for speculative debate purposes.

If i may borrow one of your quotes and use it as my own..
".....I see no handle, I can't tell whether you're speculating or claiming so all I can say is I disagree, prove it."

So how about showing both sides of a 96 dB/oct complementary passive xover, that sums to both flat magnitude and flat phase across the full spectrum.
One that has a xover summing range width in the same ballpark as LR 96's, not one that sums over octaves, and then finally rolls steeply down.


Allen, not trying to start anything...just saying, let's both be real, both be fair...
  Reply to this post

Reply


Going beyond Fourth order...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
How do you find the higher cut off of Fourth order bandpass? shank1207 Subwoofers 2 18th July 2016 11:39 AM
Fourth Order Cross over or notch filter? alvaius Multi-Way 40 28th February 2006 04:11 AM


New To Site? Need Help?

All times are GMT. The time now is 07:55 PM.


Search Engine Optimisation provided by DragonByte SEO (Pro) - vBulletin Mods & Addons Copyright © 2020 DragonByte Technologies Ltd.
Resources saved on this page: MySQL 15.00%
vBulletin Optimisation provided by vB Optimise (Pro) - vBulletin Mods & Addons Copyright © 2020 DragonByte Technologies Ltd.
Copyright ©1999-2020 diyAudio
Wiki