Parametric EQ problems - diyAudio
Go Back   Home > Forums > Source & Line > Analog Line Level
Home Forums Rules Articles diyAudio Store Gallery Wiki Blogs Register Donations FAQ Calendar Search Today's Posts Mark Forums Read

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
Thread Tools Search this Thread
Old 23rd September 2011, 11:53 PM   #1
diyAudio Member
Join Date: Sep 2011
Location: Winnipeg, Canada
Default Parametric EQ problems

I'm trying to build a parametric eq outlined near the beginning of this site, but when doing a simulation of the frequency response, I get a weird boost past 100kHz. I chose values for C1 = 0.1uF, C2 = 0.68uF, C3 = 0.015uF, C4 = 0.082uF, replaced the 51k resistor with a 200 ohm resister, and used a 10k pot instead of the 1M pot in the gyrators.

I chose those values because I would like the first band to have fmin = 280Hz, fmax = 2kHz, and the second band to have fmin = 2kHz, fmax = 15kHz. With these values and the calculations outlined on that page, I should get pretty close to the desired frequency response in the simulation(ignoring tolerances, etc.), however, I get a very weird boost as shown:

The first peak occurs at about 280-300Hz(fmin for the first band) just as I calculated, but there should also be a boost at 15kHz(fmax for the second band). Instead I get a weird boost after 100kHz
  Reply With Quote
Old 24th September 2011, 07:30 AM   #2
diyAudio Member
Join Date: Nov 2009
Location: Los Angeles
The commercial parametric equalizers I've seen use state variable filters rather than gyrators. Gyrators are common for graphic. The state variable filters allow Q , gain or frequency changes without affecting the other parameters.

There is also DSP for the more ambitious.

  Reply With Quote


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
Parametric EQ project ianmgreen Construction Tips 12 2nd April 2011 11:21 PM
parametric EQ placement perlmonkey Solid State 1 30th January 2011 12:12 AM
high Q eq or parametric qweetz Parts 0 14th September 2010 09:31 AM
semi parametric eq reap461 Parts 5 4th December 2008 08:56 PM

New To Site? Need Help?

All times are GMT. The time now is 10:39 PM.

vBulletin Optimisation provided by vB Optimise (Pro) - vBulletin Mods & Addons Copyright © 2017 DragonByte Technologies Ltd.
Copyright 1999-2017 diyAudio

Content Relevant URLs by vBSEO 3.3.2