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Old 8th April 2021, 05:31 PM   #111
Shoog is offline Shoog
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The HIFI crowd gave up on tone controls in the 80's. There was a good reason for that.

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Old 8th April 2021, 06:54 PM   #112
Lingwendil is offline Lingwendil  United States
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Shelving EQ is probably the only tone control I care for, and that's for setups that specifically need it for baffle step compensation.
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Old 8th April 2021, 06:54 PM   #113
wg_ski is offline wg_ski  United States
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Quote:
Originally Posted by kodabmx View Post
If someone can show me how to design a "simple" bass and treble control, I'll build it.

30Hz shelving EQ for bass, 16kHz shelving EQ for treble. I don't know how to do that except for parametric EQ or DSP.

This is interesting, but not simple. TC Electronic | Product | ANORM

A Baxandall won't cut the mustard.
I find that Baxandalls work fine for *me*, but only if I set the corner frequencies two octaves from where mass produced amps put them. Where they usually are, they affect the midrange too much. You donít have to put them there, you can make the cap values whatever you want. 15 dB boost at 100 Hz (and 9 at 200 along with it) is YUCK. 15 at 25 is niiiiiice, because that limits the boost at 100 and virtually all of it at 200.

But what you may be looking for is a 12dB per octave shelving network, which you cannot make (passive) with just resistors and capacitors. You can get there by by summing the output of a straight path plus a variable amplitude of the output of a 12dB/oct low pass filter (unless you are also allergic to sallen-key filters).
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Old 8th April 2021, 07:45 PM   #114
kodabmx is offline kodabmx  Canada
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A very good point about moving the frequencies in the Baxandall... For some reason I hadn't thought of that. If the corner points are extreme enough, a bell curve is good enough
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Old 8th April 2021, 07:58 PM   #115
kodabmx is offline kodabmx  Canada
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Quote:
Originally Posted by Lingwendil View Post
Shelving EQ is probably the only tone control I care for, and that's for setups that specifically need it for baffle step compensation.
A client wanted a tone control in the preamp I'm building him...

I ordered the blank first.

Then I realised it's only 5$ more for a complete. So I bought that. Then I paid Mouser like 60$ for the parts to populate the blank. FML.

12AX7 Dual Channel Baxandall Vacuum Tube Tone Board Type Low Distortion Adjust | eBay

If anyone wants to help change the frequencies from whatever they are to 30Hz/16kHz, I'm all ears Filter design isn't my strong point.
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Old 8th April 2021, 08:07 PM   #116
Chris Hornbeck is online now Chris Hornbeck  United States
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? A Baxandall tone control is already a sliding turnover frequency. It's not possible to make its frequency response slope greater than 6dB / octave.


YOS,
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Old 8th April 2021, 08:20 PM   #117
kodabmx is offline kodabmx  Canada
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That's why a Baxandall isn't good enough... 12-24db/octave would be impossible with it.

My client wants a tone control. I want a good tone control
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Old 8th April 2021, 08:36 PM   #118
wg_ski is offline wg_ski  United States
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Originally Posted by Chris Hornbeck View Post
? A Baxandall tone control is already a sliding turnover frequency. It's not possible to make its frequency response slope greater than 6dB / octave.


YOS,
Chris
Loudness controls donít do better than 6dB per octave either. There is only so much you can do with an R and a C.

To go to 12dB/oct, you need one resonator. To go to 24, you need two. Resonators can be made with an L and a C or two Cís and an *amplifier*. Inductors are big. Amplifiers use power (and potentially use feedback which you may be allergic to). Pick your poison. Baxandalls need amplifiers too. So do passive tone stacks that look like Baxandalls because you need a gain stage to get the level back.
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