Daydreaming of smooth controls...

[stonerbox]

Look up Analog's switched capacitor filter ICs (eg. LTC1068) and drive it with a simple CMOS 555 timer circuit with variable frequency and 50/50 duty cycle, if you'd like an analogue filter with some degree of latency.

Not that the other replies and suggestions not have been helpful or entertaining but this is the reply I've been longing for. Now I have something to research and test and tweak. Thank you!

[MrStab]

The delay and risk of overshoot is a bit of an undesired effect when making a notch filter, but where such precision isn't so critical (such as shelving filters) I can imagine it could be in the ballpark of what you're looking for.

[stonerbox]

The delay and risk of overshoot is a bit of an undesired effect when making a notch filter, but where such precision isn't so critical (such as shelving filters) I can imagine it could be in the ballpark of what you're looking for.

When getting rid of certain spikes or standing waves that would be very undesirable but as a subtle effect on a low pass it could evoke something smooth and sweet.



After reading your reply again and looking into the 1068 I quickly realized rolling my own filter was a no go.

The search goes on.
I wonder if Electric Druid/Someone have some sort of resistance producing controller (i.e for a PT2399) that could be delayed somehow? Making the swing between 0V to 4.5V charge up slowly when adjusting its output resistance. That would even give me the opportunity to experiment with different waveshapes too.

[MrStab]

I'm really sorry if I'm not understanding you properly, Stonerbox - I definitely don't think i did the first time - but would a sort of side-chain feeding the LED in an optocoupler help you at all here? With the LDR part in series or parallel with an RC filter? Perhaps, as you suggest, using a delay chip (or even just a slowly-charged cap, or both) in the side/CV chain?

[stonerbox]

I'm really sorry if I'm not understanding you properly, Stonerbox - I definitely don't think i did the first time -

Don't worry about it!

Here is what I am thinking (speculating), have a look at this.


This is just an example, and this particular combo might not work for adjusting a filter, but through variable voltage (0-5V TIME B10K ) the Bontempo adjusts the digital "potentiometer" in the MCP441100. Now let's say we somehow make that increase or decrease in voltage lag and I should end up with what I am looking for, latency when adjusting the-yet-to-be-designed high self.

..but would a sort of side-chain feeding the LED in an optocoupler help you at all here? With the LDR part in series or parallel with an RC filter? Perhaps, as you suggest, using a delay chip (or even just a slowly-charged cap, or both) in the side/CV chain?

Hey, that could be a lot simpler, a lot cheaper and a lot smaller too. I would need to make the LED charge (light up) and de-charge (dim) slowly, somehow.

[Fancy Lime]

Wait, you just want the shelf control to react with some delay instead of instantaneously? That's a job for a simple RC lowpass filter in the side chain, no?

[stonerbox]

Wait, you just want the shelf control to react with some delay instead of instantaneously? That's a job for a simple RC lowpass filter in the side chain, no?

Yes, that is what I am looking for.
I know what side chain is and RCs are but how would these two result in latency/delay when adjusting a shelving filter?

[Fancy Lime]

Let's say you have a control voltage to control a voltage controlled filter (how poetic ). If you install a series resistor with a large cap to ground after it between whatever sets the control voltage and the control input of the filter, then it will delay any changes in the control voltage like the regular old RC low pass filter that it is. For your purpose you probably want a long time constant in the seconds range. The Okawa Sim tool gives you the step response, which is what you need here:
http://sim.okawa-denshi.jp/en/CRlowkeisan.htm
Step response means: if the input of the RC changes abruptly, how does the output change over time. An important practical point to watch out for is the impedance of the filters control input. You want the R of the RC to be no more than 1/10th of that input impedance for predictable results.

[stonerbox]

Thank you Lime! I could not have asked for a better explanation than what you just gave me.
I recently asked for help with a gate circuit on here and the exact same RC adjusted the decay of the thing. I guess such RC network could delay adjustments to a LDR.

Question, would it really slow down both increase and decrease in Volts? I would assume a low pass only slows down decreases, while nothing in that RC prevents quick rises?

[Fancy Lime]

It would have the same effect on rising as on falling edges. If you only want it to act on one or the other, you need a diode parallel to the resistor.

[stonerbox]

Excellent! I am sure more questions will arise once I start the project.

Thank you all!