vojta
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Post by vojta on Mar 27, 2020 19:09:35 GMT
Hello everyone, I have a problem with calibration of the oscillators while following this manual. I understand the principle of stretching/compressing the scale with the trimmer pots, but I’m unable to tune C note in two octaves – by rotating trimmerpot clockwise I’m slowly reaching desired C0 to C2 span but at some point the trimmer pot stops to affect the scale (like it was at its highest value) and I’m note able to tune the C note (or any note) in two octaves. This happens with VCO module. I don’t have this problem with 2OSC/d but there is another issue. I’m able to calibrate the module so it tracks well in three octaves, but the problem is that I can’t tune it with the frequency knob lower than C# – that means the whole scale is shifted by a half tone. I can only tune it one octave up with the frequency knob at around 10 o’clock, but then I can’t play lower notes since the range of AE modular is limited by C -1 note. Has anyone got and idea what I am doing wrong? Thanks in advance for your help. |
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Post by robertlanger on Mar 27, 2020 19:40:01 GMT
Regarding the VCO, which frequencies are C0 / C2? Maybe the upper end goes too high where tracking is not stable any more (because this is a complete analog oscillator).
2OSC/d: I heard about the issue that the lowest frequency is not C but higher before. This could be fixed by a firmware modification - lets get in touch by PM. If it is clear it will be changed for the series production of course!
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Lugia
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Post by Lugia on Mar 27, 2020 20:58:10 GMT
Given that frequency for C0, I'm gonna venture a semi-guess that that might not be all that musically useful unless you've got some king-hell subs. Also, calibrating VCO scaling and tracking without the aid of a frequency counter and/or pro-grade tuner (think Strobetuner here) is a really awful idea...if you don't have one (or BOTH) of these, DON'T DO THIS. It's also a damn good idea to have an oscilloscope handy to check spectral purity of the waveforms, filter behavior, etc and a multimeter to make sure the voltages you're dealing with are where they should be while doing the above.
Screwdrivers: useful...and potentially destructive, too!
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vojta
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Post by vojta on Mar 27, 2020 22:51:04 GMT
Sorry, it was actually C1/C3 (32.7/130.81 Hz) I was tuning it to. I used an iOS app for tuning which seemed to be quite reliable and the output was just a saw wave going straight to the output.
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Lugia
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Post by Lugia on Mar 28, 2020 22:59:12 GMT
When calibrating, NEVER use anything but a sine or as close as you can get to it. You need as little of the additional harmonics as possible, as these (in excess) can actually make tuning and calibration more difficult. Really strong harmonics up above the 8th partial start to contain NON-equally-tempered pitch material, and these can be confusing to both test equipment and the "ol' reliable" human ear.
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vojta
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Post by vojta on Mar 30, 2020 7:48:53 GMT
Thanks for the advice, but I don’t think that’s the cause of the problem. I was able to easily calibrate both oscillators of the 2OSC/d module with a saw wave that way but calibrating VCO either with a square wave or any other of its output is not possible for me. It seems like the trimmer pot doesn’t have enough range for “stretching the scale” {from the manual: “Turning the trimmer clockwise stretches the scale, meaning the frequency for higher notes (= higher CV input voltage) is INCREASED”} to achieve correct tracking in more than one octave.
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Post by admin on Mar 30, 2020 7:50:38 GMT
When calibrating, NEVER use anything but a sine or as close as you can get to it. You need as little of the additional harmonics as possible, as these (in excess) can actually make tuning and calibration more difficult. Really strong harmonics up above the 8th partial start to contain NON-equally-tempered pitch material, and these can be confusing to both test equipment and the "ol' reliable" human ear. Unfortunately there isn't yet a sine wave oscillator in the AE Modular world ... but hopefully soon. |
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Lugia
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Post by Lugia on Mar 30, 2020 21:00:44 GMT
Triangle works, though...it's easy enough to "round out" with an LPF for calibration purposes.
As regards the trimmer adjustments, though...hm...Robert, could it be possible that if some other parameter has been majorly misadjusted, that that would throw off the scalar tracking adjustment? Some VCO designs can have that issue, others not so much so.
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bert
Junior Member
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Post by bert on Apr 18, 2020 18:21:12 GMT
I'm having the same issue with one of my VCO. My other two VCO work fine.
I'm also using 32.7 / 130.8 Hz.
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Post by otakumike on Apr 23, 2020 22:38:06 GMT
Sorry to hijack this thread. But where do you start for the base. Do you have the freq dial too dead centre?
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Post by otakumike on Apr 25, 2020 10:33:37 GMT
I’m really struggling with the instructions on how to calibrate these oscillators. And even the vco.
I’m using a Arturia keystep.
Firstly. Do I turn the pot all the way to the left? Also do I the switch hi/Lo.
And do I start with the 25th key without going down on Octive.
I know this has all Been explained but I some how don’t get it. I don’t understand where the start point is. And I’m very new to synths so any help would be appreciated.
Also apologies for starting another thread on this subject
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