selig wrote: ↑06 Dec 2017
I'm sure it's a feature applied to any audio level automation, but not sure about other parameters. I'm not where I can put that to the test at present, but will be interested in hearing what you discover.
I've now done some testing and found that it doesn't work quite the way you thought, though the way it does work makes a certain amount of sense. First of all, I've verified that the "attack/release" thing does indeed show up in the audio rendered by "Export Song/Loop". It appears to be a deliberate aspect of the SSL emulation (though I have no idea whether an actual SSL XL 9000 K behaves similarly). As it turns out,
every control on Reason's main mixer responds this way--no instant transitions are possible anywhere. I didn't actually try every single control of course, but I tried a reasonable enough sampling that I'm pretty sure nothing is exempt. The "attack" and "release" times all seem to be somewhere in the general range of 15ms, give or take. Also noteworthy is that, as best I can tell, automation timing IS pretty much perfectly sample-accurate when applied to main mixer controls. In other words, even though it takes ~15 ms for each change to fully kick in, you can see it starting to kick in exactly on-grid, at least when the automation points are snapped to bars or beats. I didn't look extensively enough to be absolutely certain that there are never offsets/jitter/etc., but I wasn't able to see any that struck me as significant. (This is all in the rendered audio, of course.)
Then I took a look at SubTractor. Totally different story--no "attack"/"release" when automating any of the controls, not even the master output level. Everything kicks in instantly, totally unlike the main mixer. At the same time, SubTractor DOES exhibit some timing inaccuracy in where the automation kicks in. I didn't test extensively enough to really nail down all the possible variables, but I was generally seeing the automation kick in anywhere around 3 to 6 ms later than it should. (I did compare this to the note-on/note-off as a sanity check, and those did show up as perfectly on grid, of course!) I'm not really sure what accounts for that delay, and in fact it may have nothing to do with the automation per se; more testing is obviously needed.
I strongly suspect that the behaviors of the main mixer are the idiosyncratic ones, both with respect to the "attack/release" thing and the impressive accuracy of the automation. The SubTractor behavior seems likely to be the norm, at least for the original stock Reason devices (no idea how this would shake out for REs). However, as I haven't tested any other devices yet, that's fairly speculative. As far as my original question about automation accuracy and suitability of automation for gating, I sort of feel like my original intuitions have been vindicated. In the SubTractor (and presumably most other devices), the automation transitions do happen instantly, even for the master level, and the 3 to 6 ms offset (if those numbers hold up) seems usable enough for most ordinary gating purposes, I'd think.
selig wrote: ↑06 Dec 2017
I'm also interested to hear more about the issues you've mentioned. Are you specifically talking about automation, or does this happen with CV as well? If you have time, maybe create a worst case example, if just to let us know what to avoid! I've pushed things to the point of failure in other areas of Reason, but not (yet) in this one!
I'm mainly talking about automation. CV modulation seems to suffer from a different and less dramatic version of the problem, though it's obviously a lot trickier to check given that only narrow value ranges tend to be affected. Here are instructions that will allow you to easily recreate the automation issue, using the NN-XT filter as an example (SubTractor turns out not to be affected after all). Once you've done that and can hear what I mean, I'll leave it to you to determine the extent to which CV is affected and why it seems to behave somewhat differently, and will be most interested to hear your conclusions.
- Create a new NN-XT instance
- Reset it to Init Patch
- Load sample: SH1_SAW_C3.aif from Reason 10 FSB (NN19 Sampler Patches/Synth Raw Elements/Roland SH101 Samples)
- Turn NN-XT Global Filter Res up to max
- Play and hold a note in the bass range (I think I used E2) and try to use automation to smoothly vary the Global Filter Freq from -20 to -15
You should notice awful, extreme stepping with every click of the Filter Freq. This happens regardless of how you modify the parameter--by hand, by remote, automation of any type, with CV being the sole possible exception. I find it very strange that this happens with the NN-XT filter but not the SubTractor filter. What could cause a discrepancy like that? Could this be a genuine bug that affects only some devices based on how their DSP code was written, that has somehow gone undetected all this time?