Full volume with LFO and 1Hz HP filter pro causes visualizers and spectrogram to gradually break.

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ShockWave
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Full volume with LFO and 1Hz HP filter pro causes visualizers and spectrogram to gradually break.

Post by ShockWave »

Hello again,

Ive found a bug with all visualizers that come after the LFO's including the spectrogram. This bug is caused by a velocity2ctl input at maximum velocity which is controlling the volume of LFO modules using panning type oscillations and a filter pro module set to HP 1Hz. I'm using the LFO's as a signal generator which then gets modified through a waveshaper to produce a sound. However this created a feedback type effect when the note was no longer pressed. I solved this with a HP filter pro set to 1Hz however this seems to cause all the visualizer after the LFO's to break. Sadly when i tried reproducing the bug in a project file I couldn't despite having rebuilt an exact copy of the synth from scratch. Though it is possible I might have missed something.

The strangest part of the behavior is that it breaks gradually with each full velocity note as if the sound is getting quieter despite that not being the case.

I'm on windows 10.

Here is the project file:
visualizer bug.sunvox
(15.15 KiB) Downloaded 97 times
edited for clarity
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NightRadio
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Re: Full volume with LFO and 1Hz HP filter pro causes visualizers and spectrogram to gradually break.

Post by NightRadio »

Hi!

1) You can't use the feedback loop (modules 0A -> 15 -> 07 -> 0A) without the Feedback module: https://warmplace.ru/soft/sunvox/manual.php#feedback

2) 13.Filter Pro (in HP mode) is equal to DC Blocker, which is definitely required here, because the LFO has a non-zero DC offset.
Non-zero DC offset leads to a sharp attenuation of the DC component at zero filter frequency of the Filter. This decay is further saturated with high frequencies in the WaveShaper.
How to fix:
* use DC Blocker (or Filter Pro as in your example);
* or use 0A.Filter Pro type = LP (0) - this will smooth out the above transition a bit.

3) Waveform is empty in the visualizer, because it is the mathematical sum of the left and right channel waveforms. So in case of panning LFO it will always be a straight line at some constant level. Although in some cases the WaveShaper can change this.
ShockWave
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Re: Full volume with LFO and 1Hz HP filter pro causes visualizers and spectrogram to gradually break.

Post by ShockWave »

Hi

I really appreciate your reply although I am not sure my issue came across as I have intended. I hope my response will clarify things as I am fairly new to music creation in general and have used the wrong terminology for certain things. Again really appreciate it.
NightRadio wrote: Wed Jul 27, 2022 12:38 pm Hi!

1) You can't use the feedback loop (modules 0A -> 15 -> 07 -> 0A) without the Feedback module: https://warmplace.ru/soft/sunvox/manual.php#feedback
Although I think you somewhat explained it well in your second point I am still going to clarify on what I meant.
I might have used the wrong terminology since Im not using feedback loops I didnt know how else to describe it though at the time. The effect was kind of like having an electric motor turn off in a circuit causing a voltage spike in the return direction and it only happened when the gate closed fully. since this functioned more like a pulse rather than a constant load it could be mitigated using a 1Hz HP filter.
NightRadio wrote: Wed Jul 27, 2022 12:38 pm 2) 13.Filter Pro (in HP mode) is equal to DC Blocker, which is definitely required here, because the LFO has a non-zero DC offset.
Non-zero DC offset leads to a sharp attenuation of the DC component at zero filter frequency of the Filter. This decay is further saturated with high frequencies in the WaveShaper.
How to fix:
* use DC Blocker (or Filter Pro as in your example);
* or use 0A.Filter Pro type = LP (0) - this will smooth out the above transition a bit.
Thank you that last point is really good advice I will apply that.
NightRadio wrote: Wed Jul 27, 2022 12:38 pm 3) Waveform is empty in the visualizer, because it is the mathematical sum of the left and right channel waveforms. So in case of panning LFO it will always be a straight line at some constant level. Although in some cases the WaveShaper can change this.
I understand what your saying here but I dont think thats the problem. If your situation would be the case then it would show a line(I think atleast might be wrong it depends on how you have written it) but not even a line is shown and the process is gradual and not instantaneous. The behavior is more reminiscent of reaching a limit at x=0 and this was only with each subsequent press at maximum velocity. At any other velocity it worked fine but that might have to do with how I setup velocity to control multiple other aspects of the module. The sound did not reflect this behavior however and kept playing the same way as if nothing was changing. Also the waveshaper had no influence on the effect I witnessed with this potential bug. The result was the same before and after the waveshaper regardless of wave shape although I might have been unlucky precisely picked the wave shapes to test that would have resulted in the effect I witnessed.

I hope this helps clarify the issue I was having It also never returned when I kept working the module while keeping mostly the same setup of filters and LFO's so it might have been a rare circumstance that caused this issue.
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NightRadio
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Re: Full volume with LFO and 1Hz HP filter pro causes visualizers and spectrogram to gradually break.

Post by NightRadio »

I might have used the wrong terminology since Im not using feedback loops I didnt know how else to describe it though at the time.
I understand. I didn't mean the effect you wrote about above.
I just wanted to say that you have feedback in the circuit and it doesn't work :) For this reason, module 07 will not work the way you want.
If your situation would be the case then it would show a line(I think atleast might be wrong it depends on how you have written it) but not even a line is shown and the process is gradual and not instantaneous.
Bypass 13 (Filter Pro) -> the sum of the channels = 1 -> you will see the horizontal line at the top of the 0A visualizer.
Enable 13 -> DC offset will be removed -> LFO will be centered vertically -> the sum of the channels = zero -> SunVox does not show the waveform with zero amplitude, so you can only see the level meter (max amplitude on both channels)
ShockWave
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Re: Full volume with LFO and 1Hz HP filter pro causes visualizers and spectrogram to gradually break.

Post by ShockWave »

Ah yeah sorry, thank you for being patient with me. I have added your suggestions and yeah their a definite improvement especially ur suggestion number 2 it no longer sounds like a buzz saw when I hold 2 or more notes in(unless I want them to).

So many thanks.
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