EQ Circuit before or after crossover circuit ?? - diyAudio
Go Back   Home > Forums > Source & Line > Analog Line Level

Analog Line Level Preamplifiers , Passive Pre-amps, Crossovers, etc.

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 24th April 2011, 12:25 AM   #1
diyAudio Member
 
Join Date: Sep 2005
Default EQ Circuit before or after crossover circuit ??

Hi Can someone clear this for me, I want to build a 3 way Active crossover and I want to be able to adjust frequencies, my best idea es to use EQ circuits, but I donīt know if itīs better to use active EQ before or after Crossover stage.

I was thinking to use a 3 band EQ with gyrators after each crossover stage to fine tune the frequencies...

What do you think??
  Reply With Quote
Old 24th April 2011, 09:37 AM   #2
diyAudio Member
 
s3tup's Avatar
 
Join Date: Dec 2004
Location: Israel
Depends what do you want to fix with these EQs.
If you plan to fix driver-related issues, then you probably should place the EQs on each driver's signal trace.

If you want to fix baffle problems, room EQ etc - then you should keep EQ before crossovers.

I'd suggest to place LPF after EQ section - like this
[IN] - [HPF]
.......\[EQ] - [LPF]
Then, if you'll have a hiss in EQ, it will be filtered by LPF.

3 bands for each... That's 4 opamps for each driver! (1 buffer + 3 gyrators).

I'd build a couple of simple buffer+gyrator sections, which you could place whereever you wish.
  Reply With Quote
Old 24th April 2011, 11:05 PM   #3
diyAudio Member
 
Join Date: Sep 2005
Well I wanīt to have a crossover like the comercial automotive crossovers where the frequencies are variable for fine tuning, today I experimented with NI Multisim and placed the EQ before and after Xovers but I do not see a difference,
  Reply With Quote
Old 26th April 2011, 10:29 AM   #4
diyAudio Member
 
s3tup's Avatar
 
Join Date: Dec 2004
Location: Israel
Try to sum the crossover outputs:
[HP]---[R=10k]_(test point)__[R=10k]___[GND]
[LP]---[R=10k]/
and see what you get if EQ is tuned near the crossover frequency.
Each EQ affects phase response a lot - you'll see the phase errors during summation if EQ is placed in particular driver's chain.
That phase wiggle in EQ could fix driver's phase error (as long as the hump/dip on driver's response is linear - so every frequency curve is related to phase curve, and when you fix linear response dip, you fix the phase too).
  Reply With Quote
Old 27th April 2011, 02:33 PM   #5
diyAudio Member
 
Join Date: Sep 2005
Thank you for the suggestion I will experiment and check as suggested !!
  Reply With Quote
Old 27th April 2011, 03:31 PM   #6
diyAudio Member
 
Join Date: Feb 2011
Location: Devon, UK
I don't see the point. You will have to have different low, mid and top frequencies for each drive unit, as bass won't have any top, and top no bottom. Better to have a nine band graphic equalizer and you can play to your heart's content.
  Reply With Quote
Old 27th April 2011, 08:44 PM   #7
diyAudio Member
 
Join Date: Sep 2005
Quote:
Originally Posted by cats squirrel View Post
I don't see the point. You will have to have different low, mid and top frequencies for each drive unit, as bass won't have any top, and top no bottom. Better to have a nine band graphic equalizer and you can play to your heart's content.
Quote:
Originally Posted by s3tup View Post
Depends what do you want to fix with these EQs.
If you plan to fix driver-related issues, then you probably should place the EQs on each driver's signal trace.

If you want to fix baffle problems, room EQ etc - then you should keep EQ before crossovers.

I'd suggest to place LPF after EQ section - like this
[IN] - [HPF]
.......\[EQ] - [LPF]
Then, if you'll have a hiss in EQ, it will be filtered by LPF.

3 bands for each... That's 4 opamps for each driver! (1 buffer + 3 gyrators).

I'd build a couple of simple buffer+gyrator sections, which you could place whereever you wish.


Your absolutely right, I wasnīt thinking straight, it would require 6 EQ for stereo channels, and would be hell to sync each pair not to mention the cost of all those op amps, 1 EQ before the crossover look simpler...
  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
Subwoofer input+filter+eq circuit zeus_threat Subwoofers 13 6th January 2013 08:13 PM
Remove mid range boost EQ circuit? mr.duck Analog Line Level 4 19th June 2009 06:21 AM
Crossover Circuit Boards berserker Parts 1 7th November 2007 02:17 AM
Need help on EQ circuit Buzzy Parts 3 25th September 2007 02:52 PM
Linkwitz eq circuit The Dudster Subwoofers 5 3rd November 2004 05:29 PM


New To Site? Need Help?

All times are GMT. The time now is 12:27 PM.


vBulletin Optimisation provided by vB Optimise (Pro) - vBulletin Mods & Addons Copyright © 2014 DragonByte Technologies Ltd.
Copyright Đ1999-2014 diyAudio

Content Relevant URLs by vBSEO 3.3.2