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Sub 37 Envelopes not consistent

Posted: Sun May 08, 2016 11:29 am
by ChiLam
Hi folks,

Iv'e noticed that the AMP envelope is not consistent and sounds different each time it is triggered. It sounds like sometimes it has a sharp fast attack with a click and other times it is soft and dull, without a sharp attack transient. It's quite noticeable when trying to make a chugging bass arp sound, almost like a type of phasing effect is occurring.

I have triple checked:
All Modulation is set to zero,
EG AMT at zero,
KB TRACK at zero,
GLIDE OFF,
RES & MULTIDRIVE at zero,
FILTER fully open,
Only One OSC engaged,

AMP ENV Settings: ATTACK = 0, DECAY= just under halfway, SUSTAIN = between 1 & 2, RELEASE = approx 2'o'clock

Then if I trigger one note with the ARP or Sequencer using the internal clock or external clock each 7 or so notes have a different attack. It happens even if I trigger the same note manually too. Some are nice, sharp and clicky as I would expect with the ATTACK at zero, but then some are dull and lack the sharp transient - the effect sounds sort of like phasing. Is this expected? Am I possibly overlooking something? Shouldn't it be possible to make each note be triggered in a more consistent fashion? Oh and I tried with different combinations of MULTI TRIG and RESET too - no change.

Any advice greatly appreciated. :wink:

Re: Sub 37 Envelopes not consistent

Posted: Sun May 08, 2016 1:55 pm
by LuLoop
Hi,

Is this happening also when you make first an Init setting?
And then make your setup?.

All Modulation is set to zero,
EG AMT at zero,
KB TRACK at zero,
GLIDE OFF,
RES & MULTIDRIVE at zero,
FILTER fully open,
Only One OSC engaged


Can only imagine that your mod 1 or mod 2 / filter AMT is set higher or lower then zero.


Regards Luloop.

Re: Sub 37 Envelopes not consistent

Posted: Sun May 08, 2016 3:08 pm
by ChiLam
LuLoop wrote:
Can only imagine that your mod 1 or mod 2 / filter AMT is set higher or lower then zero.

Regards Luloop.


Hey thanks, yes, it is weird - and yes, this is from an initialized preset - all modulation sources at zero. I take it your AMP envelope doesn't behave like this and is entirely consistent at the same settings?

EDIT: Tried to upload a short .wav, mp3, aif, wma to give an example but i'm told it it not allowed to upload any of these file extensions!? I tried again from scratch and initial patch, one oscillator and get the same results. The ATTACK can be set anywhere in from zero to 10ms or more, RELEASE doesn't matter either zero or max or anywhere in between. DECAY can be set anywhere from zero up to about 10ms or more. SUSTAIN anywhere too. The clicking coming and going is periodic and can be clearly heard and seen on the waveform view of the audio file. The transient clicking increases and decreases like it's being modulated but there is no modulation being set. I wish I could upload the example :C

Re: Sub 37 Envelopes not consistent

Posted: Sun May 08, 2016 4:18 pm
by ChiLam
And after all that it turns out to be another classic case of user error!!! :oops:

So, I somehow missed the large button called "KBD RESET" found in the OSC section...I had tried all the other KBD RESET buttons in the MOD sources and the KBD TRACK controls and the RESET buttons in the ENV sections but missed this one. After engaging the right button the envelope is triggering with robot consistency as I was after - hooray and sorry for wasting anybodies time.

Chugging robot arps here we come... :D

Re: Sub 37 Envelopes not consistent

Posted: Tue May 10, 2016 12:07 pm
by Amos
ChiLam wrote:And after all that it turns out to be another classic case of user error!!! :oops:

So, I somehow missed the large button called "KBD RESET" found in the OSC section...I had tried all the other KBD RESET buttons in the MOD sources and the KBD TRACK controls and the RESET buttons in the ENV sections but missed this one. After engaging the right button the envelope is triggering with robot consistency as I was after - hooray and sorry for wasting anybodies time.

Chugging robot arps here we come... :D


You got it! KB RESET in the Oscillator section is your answer.

Just a quick FYI explaining what is happening... it was never the envelopes themselves being inconsistent. The reason that the *sound* was inconsistent was because, until you turned on Osc. KB RESET, the oscillators were "free running" -- oscillating constantly at whatever frequency... and the result of this is that the oscillator signal could be at any point in its waveform at the time that the envelope fires. If the envelope happens at an instant where the oscillator signal is near zero, then you get a smoother attack, but if the envelope starts at a moment when the oscillator signal is near the top of its waveform, it makes a punchier popping sound at the start of the note. The randomness is because there was no coordination between the envelope start and the oscillator waveform. KB RESET fixes this by resetting the oscillator waveform to a consistent point at the start of a note, so that the oscillator signal hits the envelope the same way every time.

This is a little vague but I hope the idea comes across.

Re: Sub 37 Envelopes not consistent

Posted: Tue May 10, 2016 2:36 pm
by ChiLam
Great explanation thanks Amos. :D

Re: Sub 37 Envelopes not consistent

Posted: Wed May 18, 2016 6:38 pm
by ChiLam
Well, after playing again this evening a new discovery. While the KBD RESET button did solve the issues I was having it doesn't seem to work when the SUB OSC is engaged too!?

The sound is consistent with OSC 1 and OSC 2 turned on.
The sound is consistent with OSC1 and SUB OSC turned on.
As soon as I mix OSC 2 and SUB OSC together the sound becomes inconsistent.

It's funny because it seems to relate to the pitch of the OSC's since I can use the FINE TUNE knob at the far left to "stabilize" sound so that each note triggered sounds like the last, but if I change the note from say G to C on the keys then the "phasing" pattern starts happening again and each press or ARP note is defferent to the last. It's a little frustrating because the chugging deep arp sounds great on one key but totally different on another. It seems like the KBD RESET does not apply to the SUB OSC?

Help me Amos! Do you know whats happening here? :? :wink:

EDIT: This is most apparent when OSC1 OCTAVE is set to 4' and OSC2 OCTAVE is set to 8' though it does happen at other settings too. Adjusting the fine tune and moving keys has a profound effect on the rhythm of the ARP's pulsing (when using the ARP) and the way each note sounds with each keypress (if not using the ARP)

Re: Sub 37 Envelopes not consistent

Posted: Sun Jun 19, 2016 8:05 pm
by mikeh11
The sound is consistent with OSC 1 and OSC 2 turned on.
The sound is consistent with OSC1 and SUB OSC turned on.
As soon as I mix OSC 2 and SUB OSC together the sound becomes inconsistent.

Yes.

This is most apparent when OSC1 OCTAVE is set to 4' and OSC2 OCTAVE is set to 8'

Definitely. Especially with square waves! Since the Sub is also at 8', the Sub square wave can partially cancel out the Osc2 square wave at 8'.

A recipe on a Sub37 with 1.2.0 firmware:
- Init preset.
- Set both oscillators to square waves; Osc1 to 4'; Osc2 at 8'.
- Tune them close together.
- Turn on only Sub and Osc2; amp to 6.
- Short plucky amp envelope: ADSR = 0 0 1 0
- Turn ARP on, BPM about 90, hold a note.
- Can you can hear variations in the notes? Good! I call it "phasing".
- Turn on the osc KB Reset.
- Now, instead of varying note attacks, you get two types of notes:
-- 1 a louder, "solid" note
-- 2 a softer, buzzy note
- Sometimes they alternate; other times you get "Morse code" (1)

On a 'scope, the first looks like a large amplitude square wave. The buzzy note is a lower amplitude (about half!) square wave with spikes at each transition. (2)

So, somehow the Sub square wave output gets goofed up a little bit by KB Reset, sometimes.
Perhaps a bug?


(1) if you can't get this effect, play higher or lower notes; or shift the keyboard up an octave or two; or turn off KB Reset, play some notes and hear the phasing effect, then turn KB Reset back on. It's not really Morse code, it's just that the buzzy notes appear irregularly.

(2) for the spikey output, the spikes go in the opposite direction of the square wave transition. I.e., when the square wave goes up, the spike is downwards, and vice versa. Spike amplitude is dependent on Sub amp control and Osc2 amp control.

Re: Sub 37 Envelopes not consistent

Posted: Mon Jun 20, 2016 7:58 am
by voyager0500
I can confirm this as well when using KBD RESET and using the Sub Oscillator.

mikeh11 wrote:
The sound is consistent with OSC 1 and OSC 2 turned on.
The sound is consistent with OSC1 and SUB OSC turned on.
As soon as I mix OSC 2 and SUB OSC together the sound becomes inconsistent.

Yes.

This is most apparent when OSC1 OCTAVE is set to 4' and OSC2 OCTAVE is set to 8'

Definitely. Especially with square waves! Since the Sub is also at 8', the Sub square wave can partially cancel out the Osc2 square wave at 8'.

A recipe on a Sub37 with 1.2.0 firmware:
- Init preset.
- Set both oscillators to square waves; Osc1 to 4'; Osc2 at 8'.
- Tune them close together.
- Turn on only Sub and Osc2; amp to 6.
- Short plucky amp envelope: ADSR = 0 0 1 0
- Turn ARP on, BPM about 90, hold a note.
- Can you can hear variations in the notes? Good! I call it "phasing".
- Turn on the osc KB Reset.
- Now, instead of varying note attacks, you get two types of notes:
-- 1 a louder, "solid" note
-- 2 a softer, buzzy note
- Sometimes they alternate; other times you get "Morse code" (1)

On a 'scope, the first looks like a large amplitude square wave. The buzzy note is a lower amplitude (about half!) square wave with spikes at each transition. (2)

So, somehow the Sub square wave output gets goofed up a little bit by KB Reset, sometimes.
Perhaps a bug?


(1) if you can't get this effect, play higher or lower notes; or shift the keyboard up an octave or two; or turn off KB Reset, play some notes and hear the phasing effect, then turn KB Reset back on. It's not really Morse code, it's just that the buzzy notes appear irregularly.

(2) for the spikey output, the spikes go in the opposite direction of the square wave transition. I.e., when the square wave goes up, the spike is downwards, and vice versa. Spike amplitude is dependent on Sub amp control and Osc2 amp control.

Re: Sub 37 Envelopes not consistent

Posted: Mon Jun 20, 2016 1:45 pm
by ChiLam
Well, good to know it's not just mine then. I ran through the note calibration a couple of times to be sure it wasn't that but it didn't change anything.

Amos, any chance you could shine some light on this behaviour? :wink:

Re: Sub 37 Envelopes not consistent

Posted: Tue Jun 21, 2016 9:25 am
by Amos
All of these things are related to subtle phase differences between oscillators, which have the most effect on the sound during the transitory instant of the note's attack. The reason you always get a consistent sound with just osc1 or just osc2 is that the phase of the oscillator is constant relative to the attack, when KB RESET is engaged for the oscillators.

The sub-oscillator is derived from oscillator 1, using a simple comparator circuit (the input to the comparator is the osc 1 sawtooth, the output is a square wave at half the frequency). This comparator circuit doesn't get "reset" by KB RESET, it just continues doing its thing... its phase is dependent on the osc 1 phase.

What I think is happening in this specific case is that there is a little bit of play between the osc1 and osc2 frequencies, just enough the be noticeable when you dial in a very precise "feel" to the bass on one pitch, and then change to another pitch... the relationship between phases of the waveforms is so subtle and precise, in creating this "feel", that extremely tiny differences (such as you get when changing to a different key, given that the oscillators don't track with 100% digital precision) will cause the result to feel different on a new note.

One thing you can try for very consistent bass that uses both oscillators and/or the sub, is to turn on osc 2 HARD SYNC. Normally this is used for classic "sync sounds" where osc2 is pitched much higher than osc1, to create screaming harmonics... but you can also tune both oscillators to the same pitch and turn on Hard Sync, and it should just result in keeping the phase of Osc2 from ever drifting relative to osc1. Try your same bass sound with osc 2 and sub, with Hard Sync turned on, and see if it's more usable that way.

cheers,

Amos