What's that rumble?

[fluffy_little_something]

I noticed that there is some ugly rumble on higher notes with all pulse and saw waveforms, not with sine and triangle, though.

Here is an audio, it becomes more audible on headphones:
https://app.box.com/s/9ua2uz7846uzmqetgjxisyciu9ick06g
After the pause in the middle, I turn the phase knob, which has a direct impact on the rumble, although I didn't have the oscillator set to retrigger.

The patch is very basic, so the problem is not modulation:
https://app.box.com/s/y535xtzj3eu3gy9urrtyn1dmoi0grfyz

Is that aliasing or something else?

[paakie]

In your patch there is the drive set to a value higher than 0, so the filter will produce overdrive, thus harmonics. if you set the drive to 0, no rumble anymore.

[fluffy_little_something]

No, I only added a little drive because without it the signal was too quiet, despite all volume controls set to max.
On the headphones you will hear the rumble or distortion or whatever it is even when you turn the drive to zero, it is there just the same.

I hear it particularly well on the entire 6th octave, like on the audio.

[Lennard]

I can only replicate the same amount of rumble in your audio file if I turn the Drive knob to maximum. Which makes sense, since extreme distortion will add aliasing which may result in low frequencies when you slightly change the pitch (which is exactly what happens when you move the phase knob, pitch increases slightly while moving the phase up, and decreases while moving down).

When I turn the Drive to 0 the rumble is gone though.

[fluffy_little_something]

Makes me wonder, do you hear it on the audio I linked?

- If not, your ears are probably not as good as they should be.

- If so, the drive knob was set to only 1.5 out of 10 I think.
And again, I hear it with drive set to zero as well

[fluffy_little_something]

Thinking about it, what sampling frequency do you use in your DAW? I am using 96 kHz. I can't go higher, else even Sylenth1 becomes a problem when using half a dozen instances.
Just tried 192 kHz out of curiosity, then the rumble is almost gone...

[fluffy_little_something]

Wow, just noticed something unexpected. The rumble is gone when I reduce the sampling rate to 48 kHz. How is that possible? Shouldn't the audio quality improve the higher the sampling frequency?

[zvenx]

I hear it in your wave file.
Loaded your sylenth patch in Cubase and tried to replicate.
I use 44.1Khz.
I couldn't.


https://www.dropbox.com/s/cd4vvu5sschde ... e.wav?dl=0

rsp

[fluffy_little_something]

Yes, at 44.1 kHz I don't hear it, either. But at 96 it is really bad.
If it is not too much trouble, would you mind trying it at 96 kHz?

[zvenx]

Yes, at 44.1 kHz I don't hear it, either. But at 96 it is really bad.
If it is not too much trouble, would you mind trying it at 96 kHz?

np.
let me try.

yes it is there at 96

https://www.dropbox.com/s/y1iwkpth00xtk ... 6.wav?dl=0


rsp

[fluffy_little_something]

Thank you. Your audio doesn't work here (dropbox rarely does), but I am relieved you, too, hear it at 96 kHz, seems my hardware is OK Seems to be some bug in Sylenth1, then...

[paakie]

It is there ! Very strong at 96kHz SR. At 48kHz SR there are sub harmonics, too, but much lover level. Mainly noticeable on c7 to g7. I routed the clean unfiltered output through apQualizer2 and applied an 16 Poles LP at 250 Hz. Seems to be produced during calculation of the synthesised waveform itself and not in the filter stage.

[fluffy_little_something]

Maybe it is the saw, as with triangle and sine there is no such noise. I don't know how Sylenth1 works inside, but maybe the three pulse waveforms are derived from the saw as well, just like any arbitrary pulse can be created via two locked saws, one of which inverted.

[zvenx]

Thank you. Your audio doesn't work here (dropbox rarely does), but I am relieved you, too, hear it at 96 kHz, seems my hardware is OK Seems to be some bug in Sylenth1, then...

yeah I realise here you have to download the wave file or click on it and say open in a new tab/window to hear it..
rsp

[Lennard]

Ah yes I was running in 44kHz. Indeed it seems something goes wrong in 96kHz. As it doesn't seem to happen in older versions of Sylenth1, it's most likely a small bug that sneaked in while fixing the phase modulation. I'll make sure that it gets fixed in the next update!