Filter and Amp Env Questions:

1) Filter: I want to create a 6-db filter with a resonance control, I cannot seem to find any instructions on how to do this. Anyone have any clues? Is there a way to combine 2 12-db filters to do this?

2) Amp Env question, how can I make the attack time logarithmic instead of linear? I don't see any macros capable of doing this.

Before asking why, I am trying to emulate some hardware and these are settings it has and can do, it's a huge learning excercise for me as I try to push my copy of Reaktor till I break it!

 

A resonant 1-pole is kind of a rare filter type if I'm not mistaken. I'm actually not sure if you can have a resonant 1-pole filter... well I suppose if your synth has it you can have it. If you can find me some C code or something that implements it I can try and implement it in Reaktor for you.

As for making a custom envelope attack curve, you'll have to also do this manually. The thing to do would be to reset an accumulator driven by a clock oscillator to a limit set by the amount of time in the attack, and use the accumulator output and the time set by the user to calculate the curve, using whatever formula you desire.

 

Heh, being an EE, I too was a bit puzzled at the listing of a 6-dB filter with resonance. Of course, I rotated the res knob on my Nord Rack 3 and sure enough, it affects the resonance. I figured they must be using two 12-db filters in parallel somehow to obtain it, I just don't see a description of how.

As for the envelope, this is what I figured I'd have to do, what you had described. I am just going to hold the more complex things off till the end as I get everything else working. It took me long enough to generate a sine source with feedback, using a ramp function and the 'sin' math function. Works nice though.

Another thing on my list of things to do is figure out how to do DFM, or differential frequency modulation (as opposed to linear). Not much information about that available.

Thanks for the help though.

 

for the logarithmic envelope, wouldn't it be easier to just convert the output than to mess around with custom curves?

 

ok i am refering to the reaktor 4 manual:-

Ladder Filter

"Filter modelled on the classic ladder cirduit patented by Bob Moog.
It is a 4-Pole filter with different low pass outputs: 24 dB/ oct, 12 dB/ oct and 6 dB/oct falloff . It also has variable resonance and logarithmic and linear control of cutoff frequency."

"LP1 Audio output for the 6dB/ low pass filtered signal."

in the "classic macros" there are "exponential" amps and
"linear" amps both of which can be modulated by an envelope.

sowari

 

for the filter I wound chain HP/LP 1 pole FM
with peak FM EQ ( if one EQ is not enough put two or three)

for the env I'll put a shaper (cubic I think) or any math function you'd like, after the env,if you just want the attack,creat a logic function that check if the env is stabilize(ie sustain) or decreasing(decay) to control a relay to route the env through different shapers,...
or none;-)