hi-pass for tone control?

[newbold]

I was thinking about my tone control being a low-pass filter and wondering how I would approach passive tone controls in the future.

I generally use my bridge pickup on my bass for most of my playing and roll in mega lows with my neck pickup, and sometimes find there to almost be too much bottom end and in trying to be clever, thought of this:

if I swap out my volume pots for stacked vol/tone with the tone being a HIGH PASS filter, I could control how low that low would go and would add some rich harmonic blends in the mids and upper-mids of my tone and still keep the lows in on one or both of the pickups if desired.

I was also thinking this could be great when I use my synth/octave, as the lows could be pushed only by an octave pedal and would have their own definition in the spectrum of sound.

The highs would, of course, still ultimitely be controlled by my master tone.

What kinds of problems would I encounter with this?

Do you think this would be a good or bad idea and why?

What kinds of approaches with passive tone controls have worked for you if you've tried?

[mellowgerman]

I am intrigued. I'll be watching this one. I've been really into the idea of passive tone controls ever since I got a HAS-Sound Varitone switch for one of my basses a while back.
Stan Hinesley also sells a passive mid-scoop and some other stuff. really interesting.
If I could get a hi-pass for my bass, i'd do it in an instant.

Originally Posted by newbold

I was thinking about my tone control being a low-pass filter and wondering how I would approach passive tone controls in the future.

I generally use my bridge pickup on my bass for most of my playing and roll in mega lows with my neck pickup, and sometimes find there to almost be too much bottom end and in trying to be clever, thought of this:

if I swap out my volume pots for stacked vol/tone with the tone being a HIGH PASS filter, I could control how low that low would go and would add some rich harmonic blends in the mids and upper-mids of my tone and still keep the lows in on one or both of the pickups if desired.

I was also thinking this could be great when I use my synth/octave, as the lows could be pushed only by an octave pedal and would have their own definition in the spectrum of sound.

The highs would, of course, still ultimitely be controlled by my master tone.

What kinds of problems would I encounter with this?

Do you think this would be a good or bad idea and why?

What kinds of approaches with passive tone controls have worked for you if you've tried?

[lemur821]

I think it's a good idea, but not practical with a passive filter, as I understand it.

[Matthijs]

Didn't the old alembic basses have something like this?

doing this with a passive control is possible, but might have certain quirks.

What you should think about is if you want to filter at one set frequency or want to shift that frequency. On the fishman pro platinum eq there's a very handy control that shifts the filter frequency on a high pass filter. I would prefer that to a standard bass control as on a amp.

[black_labb]

a cap in parrallel with a variable resistor (pot) would work fine. just get the right cap size.

[newbold]

not practical, as the circuitry would take up too much space?

[lemur821]

Originally Posted by newbold

not practical, as the circuitry would take up too much space?

No, not practical in terms of required component values.

[newbold]

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[Stealth]

Originally Posted by lemur821

I think it's a good idea, but not practical with a passive filter, as I understand it.

Considering the fact the low-pass filter (tone control) on the bass is an RC-circuit, isn't it just a matter of reversing it into a CR-circuit to achieve a high-pass filter effect?

Come to think of it, some basses (Gibson EB3, maybe?) had a choke filter mounted on the pickup (basically, an RL circuit) that'd make a fixed cut - basically, use a trimpot instead of a fixed R and presto - high-pass filter. Trouble is, coils are cumbersome and heavy...

[slowburnaz]

Originally Posted by Stealth

Considering the fact the low-pass filter (tone control) on the bass is an RC-circuit, isn't it just a matter of reversing it into a CR-circuit to achieve a high-pass filter effect?

Come to think of it, some basses (Gibson EB3, maybe?) had a choke filter mounted on the pickup (basically, an RL circuit) that'd make a fixed cut - basically, use a trimpot instead of a fixed R and presto - high-pass filter. Trouble is, coils are cumbersome and heavy...

No need for a coil:

High-pass filter


Low-pass filter


If someone could convert this into a nice little schematic, showing how this fits into a typical tone knob-type situation, that would be cool.

Also, you'd have to play around with the values of the components to get what you wanted. This might help: High-pass filter 'explorer'

[Stealth]

Originally Posted by slowburnaz

No need for a coil:
High-pass filter

Precisely. Ergo my original CR-circuit comment.

Originally Posted by slowburnaz

If someone could convert this into a nice little schematic, showing how this fits into a typical tone knob-type situation, that would be cool.

Also, you'd have to play around with the values of the components to get what you wanted. This might help: High-pass filter 'explorer'

Actually, the only thing you have to do is swap the positions of the cap and the resistor in the schematic - and it should work.

[slowburnaz]

Originally Posted by Stealth

Precisely. Ergo my original CR-circuit comment.



Actually, the only thing you have to do is swap the positions of the cap and the resistor in the schematic - and it should work.

Yeah, but isn't the pot actually the "resistor" in this case? How would one wire this up, expressed similarly to this diagram?

Vol-Vol-Tone

I know it's probably really simple, I just can't picture how it should be done right now.

[lemur821]

Originally Posted by Stealth

Considering the fact the low-pass filter (tone control) on the bass is an RC-circuit, isn't it just a matter of reversing it into a CR-circuit to achieve a high-pass filter effect?

Yes. However I was assuming that he would want a different frequency range. Maybe not. And I'm not an expert; it's just my impression that a passive filter isn't practical in the 10s of Hz range where I think high-passing would be most useful.

[newbold]

If I could get the high-pass to affect 0-600hz
(just guessing...might want it to go to 2K or higher)
it could be really useful for controlling the mids and low mids that get pushed out.