I am getting some surprising behavior with the VCV Befaco Rampage module. The attack decay envelope has extensive “chatter” at the tail when the shape is fully counterclockwise and the range is fast, as shown below. The chatter does not occur with medium or slow range.
I’d like to know if this is modeling behavior of the actual hardware, or if it is a bug/design flaw in the VCV module.
Can someone with the actual hardware run a test and report back?
i don’t have any answers about this, but i got curious about it myself and messed around with the VCV module a bit last night. i was noticing this “chatter” with the shape knob at basically all values below 0, to varying degrees, not just at fully counterclockwise.
Thanks. I can’t tell if the range is slow (up) or fast (middle). For the best test I need the range to be fast.
I guess as a person who doesn’t use eurorack hardware much I’m not really interested if this is emulating a bad feature or it’s just a bug. It seems like a really undesirable feature, right? So even if the original hardware does this, wouldn’t it be kind of nuts for software to emulate that?
Well, being able to test an accurate rendition of a module in a virtual system like VCV could be very useful for someone to help decide if they want to buy the hardware.
Also, I think it is kind of like a lack of anti-aliasing in many VCV modules. Definitely bad when you don’t want it (most of the time for me) - but sometimes is great when the resultant sound hits the spot.
In the case of the chatter in the Rampage envelope, it works great as a snare when you ping say a Wasp filter. If it actually models the hardware, then I feel I can rely on that behavior. But if it is a bug, then that behavior will disappear if the bug is ever fixed. (I wouldn’t hold my breath)
Didn’t have time to comment yesterday but I patched this out of the actual Rampage into my Expert sleepers ES-9 then direct to the oscilloscope.
For what it’s worth, the Drunken Rampage from Frozen Wastelands does not seem to generate any chatter at any setting. If one doesn’t use the BAC feature (Blood Alcohol Level) then it functions same as the Befaco one, minus the chatter.
At which blocksize/samplerate are you running?
Tried to reproduce this in Cardinal at 256/48k and this noise-tail is definitely shorter:
My VCV is running at 48kHz, and my interface is running at 256/48kHz
I am not worried about precise behavior at this point. I’m just curious if the hardware ever does anything similar.
The length of the tail is highly variable depending on various settings. It repeatedly grows and shrinks as you sweep from shape = 0 to -1. I haven’t bother to check what happens as you adjust decay.
THanks for the report, have logged an issue: Rampage unstable at shape = -1 · Issue #44 · VCVRack/Befaco · GitHub
Definitely a bug, and wasn’t present when Rampage was monophonic. I’ve not personally worked on Rampage but will take a look. Any help welcome though!
I think I’ve tracked down the fix, took me a while in the end but learnt a bit about simd. It’s actually pretty serious and affects the operation in lots of ways when in “fast” mode (e.g. when feeding something into IN which I don’t often do tbh). I’ve pushed a fix,: Releases · hemmer/Befaco · GitHub
All fixed in my hands - no more chatter on the fast tails. Broke my snare patch, but fixed a bug!
I’ve developed a v2.5 fix for my snare by using a 2nd Rampage envelope triggered by the falling gate of the initial snare envelope. The 2nd envelope opens up a VCA to mix in some noise before the ping and noise is fed into Wasp.
All morning I thought I misunderstand Rampage and perhaps I do.
I thought it would slew a signal at the input to output, sort of like the Befaco Slew Limiter will do. But I can’t seem to get any slew at all from either channel. It is possible I am lost and need guidance.
I can slew wildly with Befaco Slew Limiter and not all with Rampage.
Trying to make a cool slope detector patch with hardware like modules.
It works fine for me. I can hook a square wave LFO to the Rampage A input in upper left, and patch the A output from center pentagram to a scope. I can then independently control the rise and fall slew rates with the left sliders. The shape knob applies to both rise and fall.
That did it, I needed to adjust range to get the expected results thanks guys.
But I assumed it had a comparable range to Slew Limiter which has much more ability to slow down a signal apparently.
