For the beginning, I will explain the title as I see it:
A parametric equalizer has three knobs for each field of frequency; one for the adjustment of the frequency, one for the level and one for the bandwidth covered by the given central frequency.
Having three bands, such an equalizer becomes difficult to use and if you are not decided of what to use it for, you will waste more time turning the buttons than listening to music.
That’s why such equalizers are almost exclusively used in the field of professional music production, where technicians and sound engineers can approximate well enough what frequencies should be set, at least as a starting point.
Personally, after I tried inclusively a 30 bands graphic equalizer, I reached the conclusion that for shaping the sound as I please, there aren’t necessary so many bands, because it takes too long to get the desired result.
I managed to obtain the sound I like - which means a slight deviation from the sound of a record that could have been better mixed – with a 4 buttons equalizer: bass, mid, mid central frequency control from 1000 to 8000 Hz and high. Which is exactly what a channel of Behringer Xenyx X1622 mixer that I owe is offering. In that case, the controls are a bit extreme, so I would search for something less aggressive, suitable to be used in the Hi-Fi system; therefore not +/-15 dB as in case of professional mixers, but something around 6 dB or a little more.
Has anyone didactic materials on this purpose? I will put here what I found, but I have to admit that I don’t master the mathematics so well, in order to calculate exactly such an equalizer. I proposed the discussion here an I would use operational amplifiers, let’s say LM833 or NE5532, perhaps 4558, as Behringer usually does, but it would be even more interesting if someone had the courage to do something like this on tubes. I propose ECC83 as active element in this case. But any constructive practical idea would be welcome. I am not in the expensive opamps field...but any suggestion is welcome.
I would like to have these specs:
Bass: frequency of control at 80 Hz, +/-6 dB
Parametric mids: +/-6 dB, control of frequency from 1 to 8 Khz
I don’t mind if the control of bandwidth appears here too, at least as a trimmer, but I’d rather like a preset, well calculated version; maybe a switch with 2 or 3 positions. Also, at +/- 6 dB, I only want to easily match the sound/I only want to adjust the sound a little. I already have the console for the extreme controls, but I will never modify so much the music I listen in my Hi-Fi setup.
It would be awesome if I’d have the scheme of the Behringer mixer, but it is untraceable.
There’s what I have for now. I will be back as I will be able to get the useful material:
Simple, Easy Parametric and Graphic EQ's, Plus Peaks and Notches
Also I received the schematic of a proffesional MIDAS parametric equaliser, a bit too sophisticated, but for sure good sounding...I’m not sure if I’m allowed to post it here, PM me if interested.
I am sure that once built, such a device will be to the liking of many music listeners.
...I am not speaking to the audiophiles, but to the lovers of musical auditions. My idea is to keep things as simple as possible, without affecting the quality of sound.
P.S. If there's already such thread, please redirect me there or move my post entirely...but it doesn't seem to be such thing, or at least some project easy to be taylored to my desired specs...
A parametric equalizer has three knobs for each field of frequency; one for the adjustment of the frequency, one for the level and one for the bandwidth covered by the given central frequency.
Having three bands, such an equalizer becomes difficult to use and if you are not decided of what to use it for, you will waste more time turning the buttons than listening to music.
That’s why such equalizers are almost exclusively used in the field of professional music production, where technicians and sound engineers can approximate well enough what frequencies should be set, at least as a starting point.
Personally, after I tried inclusively a 30 bands graphic equalizer, I reached the conclusion that for shaping the sound as I please, there aren’t necessary so many bands, because it takes too long to get the desired result.
I managed to obtain the sound I like - which means a slight deviation from the sound of a record that could have been better mixed – with a 4 buttons equalizer: bass, mid, mid central frequency control from 1000 to 8000 Hz and high. Which is exactly what a channel of Behringer Xenyx X1622 mixer that I owe is offering. In that case, the controls are a bit extreme, so I would search for something less aggressive, suitable to be used in the Hi-Fi system; therefore not +/-15 dB as in case of professional mixers, but something around 6 dB or a little more.
Has anyone didactic materials on this purpose? I will put here what I found, but I have to admit that I don’t master the mathematics so well, in order to calculate exactly such an equalizer. I proposed the discussion here an I would use operational amplifiers, let’s say LM833 or NE5532, perhaps 4558, as Behringer usually does, but it would be even more interesting if someone had the courage to do something like this on tubes. I propose ECC83 as active element in this case. But any constructive practical idea would be welcome. I am not in the expensive opamps field...but any suggestion is welcome.
I would like to have these specs:
Bass: frequency of control at 80 Hz, +/-6 dB
Parametric mids: +/-6 dB, control of frequency from 1 to 8 Khz
I don’t mind if the control of bandwidth appears here too, at least as a trimmer, but I’d rather like a preset, well calculated version; maybe a switch with 2 or 3 positions. Also, at +/- 6 dB, I only want to easily match the sound/I only want to adjust the sound a little. I already have the console for the extreme controls, but I will never modify so much the music I listen in my Hi-Fi setup.
It would be awesome if I’d have the scheme of the Behringer mixer, but it is untraceable.
There’s what I have for now. I will be back as I will be able to get the useful material:
Simple, Easy Parametric and Graphic EQ's, Plus Peaks and Notches
Also I received the schematic of a proffesional MIDAS parametric equaliser, a bit too sophisticated, but for sure good sounding...I’m not sure if I’m allowed to post it here, PM me if interested.
I am sure that once built, such a device will be to the liking of many music listeners.
...I am not speaking to the audiophiles, but to the lovers of musical auditions. My idea is to keep things as simple as possible, without affecting the quality of sound.
P.S. If there's already such thread, please redirect me there or move my post entirely...but it doesn't seem to be such thing, or at least some project easy to be taylored to my desired specs...
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I needed a simple equalizer for my home computer audio. I found a used ADC Sound Shaper One for $25. I upgraded the audio path caps to polypropylene and increased the power supply filter capacitance. It is a five band stereo EQ---60--24--1K--3.5K---10K. It now sounds good, and is amazingly useful. Best bang for the buck.
Yes, I want to make a simple stereo parametric equaliser, but customised for an easier use.
I already have a Pioneer GR 560, 7 bands graphic equaliser. It does the job, but not as expected...it trims better the lows and highs, I mean, steeper than a regular low-high eq...but the mids are not precisely enough...I use different headphones and I need the equaliser to study and level the differences between them. This seems to be done great with the parametric mids of my mixing console.
In the meantime I discovered the ESP project 150...it's a different approach than the regular gyrator or baxandall...
Parametric EQ
But also I got the original schematic of the console I am using...so I already have 3 interesting projects to test....I'm not sure it's ok to post here the entire service manual of the console, but I will cut only the parametric mids equaliser for one channel.
@Tfive: do you know such software equaliser project for Raspberry Pi 4? I am very interested...but not instead of analogic hardware...
I already have a Pioneer GR 560, 7 bands graphic equaliser. It does the job, but not as expected...it trims better the lows and highs, I mean, steeper than a regular low-high eq...but the mids are not precisely enough...I use different headphones and I need the equaliser to study and level the differences between them. This seems to be done great with the parametric mids of my mixing console.
In the meantime I discovered the ESP project 150...it's a different approach than the regular gyrator or baxandall...
Parametric EQ
But also I got the original schematic of the console I am using...so I already have 3 interesting projects to test....I'm not sure it's ok to post here the entire service manual of the console, but I will cut only the parametric mids equaliser for one channel.
@Tfive: do you know such software equaliser project for Raspberry Pi 4? I am very interested...but not instead of analogic hardware...
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The EQ as presented on the Rod Elliott pages is certainly interesting. Most studio parametric EQs, including those in your Midas console are state variable filters. A state variable allows independent adjust of gain/cut, frequency and 'Q'. State variable filters usually require four op amps and a fist full capacitors and resistors per filter to realize. One of the best sounding studio grade parametric EQs is in the public domain, that being Berry Porter's Net-EQ. The Net-EQ was originally designed for use in the Cadac large format mixing consoles. I see these people are selling circuit boards to those that want to build their own. Barry Porter NETEQ PCB | Analog Classics
In my experience, different types of EQs are needed for different applications. A full parametric EQ (controls for frequency, amount of boost/cut, and filter Q) are most useful when EQing a single source---a vocal, a piano, a saxophone, a violin. Maybe even a group of the same sort of instruments--a string or horn section. But when EQing a complete stereo MIX (such as a finished record), I think 10-band graphic equalizers are more easily and more effectively used.
Not much information about that EQ on that link---a schematic would be helpful. What ranges and amounts of boost/cut are available? What ICs and capacitors are recommended?........ Is there a link for better info?
Barry Porter 'Net-EQ' docs
Yea, I see that the Net-EQ papers have disappeared for the most part. If anybody is truly interested I have details. In the last 20 years I have built several variations of his EQ. It's a good and reliable circuit.
Yea, I see that the Net-EQ papers have disappeared for the most part. If anybody is truly interested I have details. In the last 20 years I have built several variations of his EQ. It's a good and reliable circuit.
Thanks for posting the schematic. BUT, I find that EQ circuit to have a LOT of shortcomings. It is way over-complicated and uses too many opamps, and its dependence on triple-ganged potentiometers is just impractical and WAY too expensive to implement. It's also surprising to see bipolar opamps (NE5532) with their very high input bias currents used in a circuit with pots--they'll have DC on them and surely 'scratchy' when adjusted.
dotneck335 said, " I find that EQ circuit to have a LOT of shortcomings. It is way over-complicated and uses too many opamps ..."
In my experience simpler isn't always better. I have been building Barry's Net-EQ in various forms for 20 plus years and it's always been a positive experience. Four opamps per section is a standard count for a state variable filter. Barry's Net-EQ is a state variable filter.
dotneck335 please share some of your favorite parametric EQ circuits. We all have an interest.
In my experience simpler isn't always better. I have been building Barry's Net-EQ in various forms for 20 plus years and it's always been a positive experience. Four opamps per section is a standard count for a state variable filter. Barry's Net-EQ is a state variable filter.
dotneck335 please share some of your favorite parametric EQ circuits. We all have an interest.
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