Graphic equalisers

Subjects that don't have their own home
Post Reply
Ant
Shed dweller
Posts: 2332
Joined: Mon Jul 31, 2017 6:45 pm
Location: Yorkshire

#1 Graphic equalisers

Post by Ant »

Simple question, probably with a massively complicated answer, probably one that our chris is best placed to answer.
Is there any none cobblers hifi mag reason not use a graphic equaliser to tweak system response using rew/interface/mic.

Reason being, i am curious to see what balance i can get out of the speakers, mainly at the very bottom end and around fr. Not necessarily more bass, im looking at response hole plugging and smoother rollof. I dont want to do it in software because i cant feed the tts through it and wouldnt want to anyway because of my luddite tendencies

Opinions?
Also starring Rex Hamilton as Abraham Lincoln

www.bte-designs.weebly.com
Max N
Old Hand
Posts: 1453
Joined: Thu Aug 16, 2007 6:10 pm

#2 Re: Graphic equalisers

Post by Max N »

I remember the days when graphic equalisers (along with FFT type displays) were common, often built into the system.
Some of them had a bypass or direct switch, and I can’t remember hearing a big difference.
I suppose there are filters - are they passive? Would they introduce phase lag?
User avatar
rowuk
Old Hand
Posts: 453
Joined: Sun Jun 01, 2014 2:50 pm
Location: Germany

#3 Re: Graphic equalisers

Post by rowuk »

Linkwitz Transformation is a possibility here. Here is Rod Elliots/Jeremy Wolfs take and circuit:
https://sound-au.com/linkwitz-transform.htm
https://sound-au.com/project71.htm
https://sound-au.com/linkxfrm.zip

Linkwitz enjoyed great acceptance - even in the HiFi magazine world.
Whenever I feel blue, I start breathing again.
User avatar
Mike H
Amstrad Tower of Power
Posts: 20157
Joined: Sat Oct 04, 2008 5:38 pm
Location: The Fens
Contact:

#4 Re: Graphic equalisers

Post by Mike H »

Had a cheap one from Maplin once, but then my system got better, and I realized it sounded really naff. Could have just been because of the nasty slider pots I suppose. Pretty sure it used op-amp gyrator circuits to emulate inductors. As there were 10 bands for each L and R channels, lots of components in the signal paths... doubtless SMD... I seem to remember there was a 'daughter board', or maybe two of them, one for each channel, containing the 'dark art bits', and dipped in grey resin (to keep it secret?).
 
"No matter how fast light travels it finds that the darkness has always got there first, and is waiting for it."
brig001
Old Hand
Posts: 550
Joined: Sat Nov 13, 2010 9:56 pm
Location: Back home in Preston now

#5 Re: Graphic equalisers

Post by brig001 »

I think the only problem with using a graphic EQ for that is that it is unlikely to have the frequency that you need. I have a hole on the left speaker at 70Hz due to a bay window and plug it with a boost on the right speaker. It needs a Q of 5, so quite narrow

I think using DSP is the way forward, even if it is just to find out exactly what you need, but it sounds like you don’t want to go down that road as a permanent solution

Do you know what exactly is required?
Rod Elliot has some circuits for parametric EQ which might be more suitable

Brian
Post Reply