Which Graphic Equalizer Circuit Topology provides best Sonic Quality ? "Constant-Q" ?
There are several topologies for graphic equalizer.
Good known is the common 'gyrator' tuned circuit - mostly to find in commercial devices. This graphic EQ circuits have a Q, that is dependent on the setting of the pot (non constant Q) - actually a disadvantage for such a topology - go to
How to build 10 Band Graphic Equalizer - circuit diagram
6 BAND GRAPHIC EQUALIZER CIRCUIT USING 741 OP-AMP SCHEMATIC DIAGRAM | Wiring Diagram
http://www.diyaudio.com/forums/analog-line-level/245883-10-band-equalizer-based-lm833.html
A better solution seems to be the less common "Multiple Feedback Bandpass Filter" topology for each frequency. This one maintains the same Q (i. e. same bandwidth) at all settings of the pot, and this I have found by Rod Elliott - go to
Expandable Graphic Equaliser
and
Musical Instrument Graphic Equaliser
The only commercial products I know, which have this topology, are the models "RE27" and "RE14" from RAINE so as ARX EQ260 - go to
Constant-Q Graphic Equalizers
http://electroff.narod.ru/docs/files1/constanq.pdf
http://www.rane.com/pdf/old/re27man.pdf
http://www.ece.rochester.edu/~zduan/teaching/ece472/reading/ConstantQ_Graphic_Equalizers.pdf
Rane RE27 Realtime Equalizer | eBay
ARX*FAQ - all about Graphic EQs and why ours are better
ARX EQ260 dual channel 1/3 octave graphic EQ
Pros and cons of constant-Q and non constant-Q are discussed here - unfortunately not in order to the sound quality:
https://www.gearslutz.com/board/geekslutz-forum/428878-advantage-proportional-q-v-s-constant-q.html
Which graphic equalizer topology I should prefer in order to became the best sound quality ?
And a second question:
What is important for select the appropriate operational amplifier IC's for each topology (there are an extremely wide range on the marked in the meantime and I have heard, that both MFB- and gyrator applications need other requirements in order to the internal circuits than linear applications like preamp/line stages and RIAA head amps)?
I want to have an 1/3 octave equalizer with adjusting range of -10 to +10 db or more for an use in problematic listening room environments.
This provides an easy verification from the possibilities of sound improvements.
In the moment I want to have such an equalizer for the linearization the transmission of a certainly rail from an expensive horn system between 60Hz and 600Hz (increase between 60Hz and 200Hz and decrease between 200Hz and 600Hz) - but without suffering of the sonic quality at whole. - go to the third image (left graph) at post #3 under
http://www.diyaudio.com/forums/mult...-subwoofer-4-pcs-precision-devices-pd184.html
Thank you very much for advices.
Follow URLs don't provide the wanted hints:
http://www.diyaudio.com/forums/anal...band-eq-constant-q-conventional-topology.html
http://www.diyaudio.com/forums/analog-line-level/241239-custom-equalizer-design-needed.html
http://www.diyaudio.com/forums/analog-line-level/245883-10-band-equalizer-based-lm833.html
http://www.diyaudio.com/forums/subwoofers/243879-so-few-comments-eq.html
http://www.diyaudio.com/forums/parts/76710-graphic-equalizer.html
http://www.diyaudio.com/forums/parts/105785-graphic-equalizer.html
http://www.diyaudio.com/forums/solid-state/119063-diy-graphic-equalizer.html
http://www.diyaudio.com/forums/solid-state/117188-eq-bjt-gyrator.html
http://www.diyaudio.com/forums/tubes-valves/104759-graphic-1-3-octave-tube-equaliser.html
There are several topologies for graphic equalizer.
Good known is the common 'gyrator' tuned circuit - mostly to find in commercial devices. This graphic EQ circuits have a Q, that is dependent on the setting of the pot (non constant Q) - actually a disadvantage for such a topology - go to
How to build 10 Band Graphic Equalizer - circuit diagram
6 BAND GRAPHIC EQUALIZER CIRCUIT USING 741 OP-AMP SCHEMATIC DIAGRAM | Wiring Diagram
http://www.diyaudio.com/forums/analog-line-level/245883-10-band-equalizer-based-lm833.html
A better solution seems to be the less common "Multiple Feedback Bandpass Filter" topology for each frequency. This one maintains the same Q (i. e. same bandwidth) at all settings of the pot, and this I have found by Rod Elliott - go to
Expandable Graphic Equaliser
and
Musical Instrument Graphic Equaliser
The only commercial products I know, which have this topology, are the models "RE27" and "RE14" from RAINE so as ARX EQ260 - go to
Constant-Q Graphic Equalizers
http://electroff.narod.ru/docs/files1/constanq.pdf
http://www.rane.com/pdf/old/re27man.pdf
http://www.ece.rochester.edu/~zduan/teaching/ece472/reading/ConstantQ_Graphic_Equalizers.pdf
Rane RE27 Realtime Equalizer | eBay
ARX*FAQ - all about Graphic EQs and why ours are better
ARX EQ260 dual channel 1/3 octave graphic EQ
Pros and cons of constant-Q and non constant-Q are discussed here - unfortunately not in order to the sound quality:
https://www.gearslutz.com/board/geekslutz-forum/428878-advantage-proportional-q-v-s-constant-q.html
Which graphic equalizer topology I should prefer in order to became the best sound quality ?
And a second question:
What is important for select the appropriate operational amplifier IC's for each topology (there are an extremely wide range on the marked in the meantime and I have heard, that both MFB- and gyrator applications need other requirements in order to the internal circuits than linear applications like preamp/line stages and RIAA head amps)?
I want to have an 1/3 octave equalizer with adjusting range of -10 to +10 db or more for an use in problematic listening room environments.
This provides an easy verification from the possibilities of sound improvements.
In the moment I want to have such an equalizer for the linearization the transmission of a certainly rail from an expensive horn system between 60Hz and 600Hz (increase between 60Hz and 200Hz and decrease between 200Hz and 600Hz) - but without suffering of the sonic quality at whole. - go to the third image (left graph) at post #3 under
http://www.diyaudio.com/forums/mult...-subwoofer-4-pcs-precision-devices-pd184.html
Thank you very much for advices.
Follow URLs don't provide the wanted hints:
http://www.diyaudio.com/forums/anal...band-eq-constant-q-conventional-topology.html
http://www.diyaudio.com/forums/analog-line-level/241239-custom-equalizer-design-needed.html
http://www.diyaudio.com/forums/analog-line-level/245883-10-band-equalizer-based-lm833.html
http://www.diyaudio.com/forums/subwoofers/243879-so-few-comments-eq.html
http://www.diyaudio.com/forums/parts/76710-graphic-equalizer.html
http://www.diyaudio.com/forums/parts/105785-graphic-equalizer.html
http://www.diyaudio.com/forums/solid-state/119063-diy-graphic-equalizer.html
http://www.diyaudio.com/forums/solid-state/117188-eq-bjt-gyrator.html
http://www.diyaudio.com/forums/tubes-valves/104759-graphic-1-3-octave-tube-equaliser.html
Last edited:
Yes Constant Q is the best at staying constant !
I designed & built a bass 1/4 octave EQ many years ago, & will tell you this.
More bands require higher Q & that requires OpAmps with higher bandwidths. Otherwise they won't perform as expected ! But, that can lead to oscillation, so great care needs to be taken with the circuit design.
Also, splitting & then combining the bands into multiple odd/even sections, helps too.
Fortunately, my EQ works fine
Unless you find, or copy a circuit, & build the PCB & it Exactly, you could have problems.
I've used Rane many times over the years, & highly recommend them. I would save yourself a lot of time, & possibly trouble, & just buy one, maybe second hand
I designed & built a bass 1/4 octave EQ many years ago, & will tell you this.
More bands require higher Q & that requires OpAmps with higher bandwidths. Otherwise they won't perform as expected ! But, that can lead to oscillation, so great care needs to be taken with the circuit design.
Also, splitting & then combining the bands into multiple odd/even sections, helps too.
Fortunately, my EQ works fine
Unless you find, or copy a circuit, & build the PCB & it Exactly, you could have problems.
I've used Rane many times over the years, & highly recommend them. I would save yourself a lot of time, & possibly trouble, & just buy one, maybe second hand
Good information - thank you for your reply. I will looking arround for two pieces RE27 from RANE in used condition - like this no longer available offer
2 Stück Rane RE-27 EQ und Analyzer incl. 1 original Messmic für FOH oder Monitor | eBay
2 Stück Rane RE-27 EQ und Analyzer incl. 1 original Messmic für FOH oder Monitor | eBay
There are other models of such equalizer devices from RANE, e. G. GE30, ME30, ME60, GQ30 and GE60.
Rane GE 30 Graphic Equalizer 2 x 30 Band, defekt | eBay
Rane ME 30 Graphic Equalizer 2 x 30 Band | eBay
RANE GQ 30 - 2 Stück graphic equalizer (kein Yamaha EQ 550) | eBay
RANE GQ 30 - 2 Stück graphic equalizer | eBay
Rane GE60 Equalizer | eBay
RANE GE 60 stereo 1/3 Oktav Equalizer mit Hoch- und Tiefpass | eBay
Rane Made in USA ME60 Rack Mountable Dual Channel Graphic Equalizer | eBay
I asume, "60" means two-channel and "30" one-channel version.
But what about the differences concerning sound quality between this models ?
And which operational amplifier IC's was used from RANE ?
Thank you for advices.
Rane GE 30 Graphic Equalizer 2 x 30 Band, defekt | eBay
Rane ME 30 Graphic Equalizer 2 x 30 Band | eBay
RANE GQ 30 - 2 Stück graphic equalizer (kein Yamaha EQ 550) | eBay
RANE GQ 30 - 2 Stück graphic equalizer | eBay
Rane GE60 Equalizer | eBay
RANE GE 60 stereo 1/3 Oktav Equalizer mit Hoch- und Tiefpass | eBay
Rane Made in USA ME60 Rack Mountable Dual Channel Graphic Equalizer | eBay
I asume, "60" means two-channel and "30" one-channel version.
But what about the differences concerning sound quality between this models ?
And which operational amplifier IC's was used from RANE ?
Thank you for advices.
There are not to find images from inside of RANE equalizers on the web. Who can upload some images of various models like GE60, RE27 etc ?
The only image of RANE GE60, which I discover under
http://www.livesoundint.com/archives/2003/july/quest/quest.php
is no high resolution unfortunately.
Thank you very much.
The only image of RANE GE60, which I discover under
http://www.livesoundint.com/archives/2003/july/quest/quest.php
is no high resolution unfortunately.
Thank you very much.
Last edited:
exactly - I like that very much.
In the meantime I have found a RANE GE60 and a BSS FCS960 in used condition include service-manuals and schematics. My impression from listening test of both you will find under post #6 - go to
http://www.diyaudio.com/forums/mult...-subwoofer-4-pcs-precision-devices-pd184.html
All RANE service manuals are available on their download portal and all BSS service manuals from your local distributor as PDF file via email.
RANE uses the NE5532 and the µPC4574C from NEC - go to
http://pdf1.alldatasheet.com/datasheet-pdf/view/6773/NEC/UPC4574C.html
This type I have never seen before - I think, the developers of RANE have make many listening tests
before OPA-IC choice for serial production.
BSS uses also NE5532 but for second model TL072 - obviously not as good as uPC4574C.
Last edited:
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They sure are, that's how/why I got a cheap Rane on ebay to cut a fews peaks on my subs, great for this job, modified it to 1/6 octave at low frequencies, didn't expect to get away with it..........but did
Agreed, there is something 'good' sounding about these EQ's used as FOH final send EQ.
Dan.
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