Sub 37 waveshape oscillator's

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sicil
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Sub 37 waveshape oscillator's

Post by sicil » Fri Feb 24, 2017 6:04 pm

Just a question as regard the sound generated by the three wave shapes of the three oscillators in Sub 37.
Is there any difference between the square wave generated by the Sub Oscillator and the square wave generated by OSC1 or OSC2? I have noted that when I put the knob of OSC1/OSC2 in the position of the square wave indicator the timbre of sound is quite different from that one generated by the Sub Osc, and they should be both “square waves". Of course I took care for working them at the same octave.
My sensation is based on what I ear, and what I see is that if you compare the sound coming from the three square waves on OSC1, Sub Osc and OSC2, separately, they are different; or better, the comparison shows no difference if you compare OSC1 and OSC2 (they are practically the same) but the difference exists if you compare Sub Osc with OSC1 or OSC2. Practically, Sub Osc is by default only square wave but is appear different, in the form of sound, compared to the square wave coming from OSC1 or OSC2.
In principle I expected they should produce the same sound but it is not the case; I don’t know if I’m in mistake in using something or if it is normal.
Has someone tested it? Do you know the motivation?

dalahorse
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Re: Sub 37 waveshape oscillator's

Post by dalahorse » Fri Feb 24, 2017 10:37 pm

I find that my OSC1,2 and SUB are capable of producing the same square shape. The SUB requires more gain to produce the same amplitude as the OSCs. We agree that OSC1 and 2 can produce the same square. Therefore, if you set OSC1 and octave up from OSC2, you can compare OSC2 and SUB (always 1 octave below OSC1) until everything matches.

I find that, if I set SUB to gain 7 and OSC2 to gain 5, their amplitudes are equal. Then it's just a matter of twiddling OSC2's shape to match the shape and duty cycle of SUB. If I put the shape knob ever so slightly to the left of the square symbol, it's shape and duty cycle are the same the SUB.

Do you have a scope? That's how I matched everything up.
Dalahorse
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dalahorse
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Re: Sub 37 waveshape oscillator's

Post by dalahorse » Fri Feb 24, 2017 10:53 pm

Here are my settings:

http://imgur.com/AiJjIIc

This is SUB and OSC2 in order:

http://imgur.com/W9ABVhl
http://imgur.com/mDraFSm
Dalahorse
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sicil
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Re: Sub 37 waveshape oscillator's

Post by sicil » Sat Feb 25, 2017 3:43 pm

Think you for your comments. I will try your suggestion and let you know back.
My main problem was to have the same timbre in the sound riproduced by OSc1, OSC2 and Sub when OSC1 and OSC2 work in the square wave (as Sub by default). I wasn't able to obtain, unless OSC1 and OSC2 are affected by some default parameters and Sub not.
For example I tried to do the same with Minimoog and it works perfectly. Is there any difference?

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Chimponaut
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Re: Sub 37 waveshape oscillator's

Post by Chimponaut » Sat Feb 25, 2017 3:48 pm

If you really need OSC 1 or 2 to be a perfect square wave you might need to use an oscilloscope when dialing it in. The knobs for the wave forms are never exactly in line with the graphics printed on the panel. My perfect square wave happens just beyond where the square wave graphic is on the panel. So pointing the knob to the square wave graphic is not going to get you a perfect square wave. Nature of analogue I guess. There is a knob calibration routine available for the Sub37 but I haven't needed to do this yet. Recalibrating might get the knobs and graphics more in line so to speak. The more I work with analog synths the more I appreciate these little inconsistencies.

Ahhh. Just thought of something else that could be affecting the waveform. One thing I've noticed when using the editor to tweak sounds. When you zero out a knob on the hardware, (Especially the Mod Bus Amount Knobs...filter amount, pitch amount etc.) the editor and the hardware don't quite get to zero like they should. Hover over the various knobs and wait for the editor to show their actual value. If it isn't 8192 then they are modulating the sound. Alt click the knobs to set them to zero which is shown as 8192. Do this for all the modulation amount knobs. When I zero the knobs on the Hardware, the editor shows their value as 8256. And I can hear the modulation happening even with that small amount of offset.

Hmm...I guess I might need to do the calibration routine myself but setting those knobs to zero on the editor has become a routine for me.
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funkyhammond
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Re: Sub 37 waveshape oscillator's

Post by funkyhammond » Sat Feb 25, 2017 8:35 pm

dalahorse wrote:The SUB requires more gain to produce the same amplitude as the OSCs.


An important detail. A different volume/amplitude can change the perceived quality of the sound.

I agree, use an oscilloscope if you want to get exact. Same goes for the sawtooth wave. When I was first doing this, I plugged my Sub 37 into an audio interface into my laptop and used a software oscilloscope to find the knob position of the pure sawtooth wave and pure square wave. This had the side benefit of training my ear so that I can now pretty much hear where the pure waveforms are along the variable knob. But I still decided to save "Init Saw" and "Init Square" presets so that I can quickly start off any new sound and be sure it is a pure sawtooth or pure square wave.

funkyhammond
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Re: Sub 37 waveshape oscillator's

Post by funkyhammond » Sat Feb 25, 2017 8:43 pm

Chimponaut wrote:There is a knob calibration routine available for the Sub37 but I haven't needed to do this yet.


Did you make that up? :) I'm just a new Sub 37 owner but I don't see that in the manual.

dalahorse
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Re: Sub 37 waveshape oscillator's

Post by dalahorse » Sat Feb 25, 2017 9:39 pm

I think the main message here is that an oscilloscope is the best tool for identifying waveforms. You only need something wth 20kHz resolution. So an old as dirt Tek will suffice. (I use a 2215.) theyre really handy tools for any analog synth application!
Dalahorse
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breun
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Re: Sub 37 waveshape oscillator's

Post by breun » Sat Feb 25, 2017 9:45 pm

funkyhammond wrote:
Chimponaut wrote:There is a knob calibration routine available for the Sub37 but I haven't needed to do this yet.


Did you make that up? :) I'm just a new Sub 37 owner but I don't see that in the manual.


It's not in the manual, but it exists. You're advised to run it after swapping out a board for instance and Moog support will make sure you recieve the files and instructions for that. Normally the pots come calibrated from the factory.

sicil
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Re: Sub 37 waveshape oscillator's

Post by sicil » Sun Feb 26, 2017 4:18 am

Chimponaut wrote:If you really need OSC 1 or 2 to be a perfect square wave you might need to use an oscilloscope when dialing it in.

Hmm...I guess I might need to do the calibration routine myself but setting those knobs to zero on the editor has become a routine for me.


I need OSC1 and OSC2 have the same square wave as Sub OSC.
DOes it means that Sub OSC has its own fixed calibration (in effect you could change only the volume) and the other not? But this is exactly what I wasn't to do: changing the OSC 1 and OSC2 parameters in order to arrive to the same wave square of Sub OSC

sicil
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Re: Sub 37 waveshape oscillator's

Post by sicil » Sun Feb 26, 2017 4:23 am

Sorry! There is a typing mistake in my last sentence.
I would like to write: ".........this is exactly what I want to do"

DrJustice
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Re: Sub 37 waveshape oscillator's

Post by DrJustice » Sun Feb 26, 2017 3:32 pm

sicil wrote:...
DOes it means that Sub OSC has its own fixed calibration (in effect you could change only the volume) and the other not? But this is exactly what I wasn't to do: changing the OSC 1 and OSC2 parameters in order to arrive to the same wave square of Sub OSC

The sub oscillator is most probably derived from oscillator 1's core by dividing the frequency by 2 using a (digital) flip-flop - same trick as in all analogue synths. I.e. it does not use the same wave shaping as the main oscillators and will not be exactly identical to them.

sicil
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Re: Sub 37 waveshape oscillator's

Post by sicil » Mon Feb 27, 2017 2:00 pm

dalahorse wrote:I find that my OSC1,2 and SUB are capable of producing the same square shape. The SUB requires more gain to produce the same amplitude as the OSCs. We agree that OSC1 and 2 can produce the same square. Therefore, if you set OSC1 and octave up from OSC2, you can compare OSC2 and SUB (always 1 octave below OSC1) until everything matches.

I find that, if I set SUB to gain 7 and OSC2 to gain 5, their amplitudes are equal. Then it's just a matter of twiddling OSC2's shape to match the shape and duty cycle of SUB. If I put the shape knob ever so slightly to the left of the square symbol, it's shape and duty cycle are the same the SUB.

Do you have a scope? That's how I matched everything up.


I have tried and I verified that it happens the same for me. Settting of gain is in effect 7 to 5 has reported by you; the shape knob has to be slightly to the left of square symbol

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