This is a repost from: https://club.tidalcycles.org/t/innard-help-problems-with-…globaldirteffects-while-coding-a-compressor/3397
System:
Win8.1, SC 3.12.0, SD 1.7.2, Tidal 1.7.8
---
I'm trying to make a compressor for SuperDirt, specifically because I want to achieve " https://club.tidalcycles.org/t/sidechain-compression-in-tidal/509?u=ritchse ". I've been running into many problems and my main concern right now is default values.
**Setup**
I added the global effect to the orbits globalEffects array:
```supercollider
~dirt.orbits.do { |x|
var l = x.globalEffects.size;
x.globalEffects = x.globalEffects.insert(l-2,
GlobalDirtEffect(\dirt_compressor,['comp','thresh','atktime','reltime','upcomp','makeup','sidechain']));
x.initNodeTree;
};
```
I defined some default values to the arguments of the SynthDef as one usually does:
```supercollider
~dryBuses = [];
~dirt.orbits.do { |x|
~dryBuses = ~dryBuses ++ x.dryBus
}
(
SynthDef.new("dirt_compressor" ++ ~dirt.numChannels,
{|dryBus, effectBus, comp=1, thresh=0.5, atktime=0.01, reltime=0.1, upcomp=1, makeup=1, sidechain=(-1)|
var sound, in, control, chs;
chs = ~dirt.numChannels;
in = In.ar(dryBus, chs);
control = In.ar(Select.kr(sidechain+1,[in]++~dryBuses),2);
sound = Compander.ar(in, control, thresh: thresh, slopeAbove: (1/comp),
clampTime: atktime, relaxTime: reltime, mul: makeup, slopeBelow: (1/upcomp));
Out.ar(effectBus, sound)
}, [\ir, \ir]).add;
s.freeAll;
)
```
And set my params in tidal as such:
```haskell
let comp = pF "comp" -- compression ratio
thresh = pF "thresh" -- threshold
atktime = pF "atktime" -- attack time
reltime = pF "reltime" -- release time
upcomp = pF "upcomp" --upwards compression ratio
makeup = pF "makeup" --amplitude of the output
sidechain = pI "sidechain" --orbit from which to sidechain
```
**Results**
```haskell
d1 $ s "bd*2" # makeup 1 # comp 1 # thresh 1
```
^ This is a neutral state of compression, nothing is happening, and sound is coming out as expected: the same as with no effects.
```haskell
d1 $ s "bd*2" # makeup 0 # comp 1 # thresh 1
```
^ This should produce no sound, yet it does, at a lower volume than before. I'd say about half the volume; so, is it running on parallel?
```haskell
d1 $ s "bd*2"
```
^ This should sound the same as in the beginning, but it sounds the same as the previous example.
I figured it must have to do with default values or something so I checked the node tree:
```supercollider
8768 dirt_compressor2
dryBus: 48 effectBus: 50 comp: 0 thresh: 0 atktime: 0.0099999997764826 reltime: 0.10000000149012 upcomp: 1 makeup: 0 sidechain: -1
8767 dirt_rms2
```
Here I run into my first problem: **When erasing a paramater, it doesn't go back into its default value**.
I'm guessing SC just ignores the last change of values into `0` since it would generate a division by zero error, hence the same output as before.
```haskell
d1 $ s "bbtdr*2" # makeup 1 # comp 1 # thresh 1
```
^ This one is mind-boggling to me. After that mess of division by zero, when I try to go back into the neutral state of compression, now I hear nothing! There's no output.
Here's the whole node tree of the first orbit:
```supercollider
2 group
9347 group
-101992 dirt_sample_2_2
out: 46 bufnum: 44 sustain: 0.41246938705444 begin: 0 end: 1 speed: 1 endSpeed: 1 freq: 261.62557983398 pan: 0 span: 1
-102000 dirt_gate2
out: 48 in: 46 sustain: 0.41246938705444 fadeInTime: 0 fadeTime: 0.0010000000474975 gain: 1 overgain: 0 amp: 0.40000000596046 sample: 1436622976 gateSample: 0 cutAll: 0
8771 dirt_delay2
dryBus: 48 effectBus: 50 gate: 1 delaytime: 0 delayfeedback: 0 delaySend: 1 delayAmp: 0 lock: 0 cps: 0.5625 resumed: 0
8770 dirt_reverb2
dryBus: 48 effectBus: 50 gate: 1 room: 0 size: 0.10000000149012 dry: 0 resumed: 0
8769 dirt_leslie2
dryBus: 48 effectBus: 50 gate: 1 leslie: 0.5 lrate: 6.6999998092651 lsize: 0.30000001192093 resumed: 0
8768 dirt_compressor2
dryBus: 48 effectBus: 50 comp: 1 thresh: 1 atktime: 0.0099999997764826 reltime: 0.10000000149012 upcomp: 1 makeup: 1 sidechain: -1
8767 dirt_rms2
dryBus: 48 effectBus: 50 gate: 1 rmsReplyRate: 0 rmsPeakLag: 0 orbitIndex: 0 resumed: 0
8766 dirt_monitor2
dryBus: 48 effectBus: 50 outBus: 0 gate: 1 limitertype: 1 resumed: 0
```
I realized that every global effect except the one I'm trying to add has the argument `resmued` at the end. I tried looking for it in the SuperDirt repo but couldn't really figure out what it is exactly.
**Final questions**
* What is the 'resumed' argument in all GlobalDirtEffect's?
* How do I make it so parameters go back into their default value state when erasing them from Tidal code?
* Why does setting the 'makeup' to 0 still produce a fair amount of sound?
*Thank you for reading all this mess ! Love*