Author Topic: pitch calibration question  (Read 348 times)

pitch calibration question

« on: February 26, 2017, 09:55:53 PM »
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leafcut7er

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I'm having trouble calibrating the 1v/oct input. It did not appear to hold the right pitch (A4) when I was trying to tune it with a MIDI note, so I attempted to calibrate it using the instructions in the manual. I'm very confused about the instructions, though, and I doubt I'm doing this right. I understand where the value dial needs to be for D#2 and A4, but what about the function dial? should it be in coarse or range mode when I begin pressing it in to calibrate the device? Should I have it in coarse mode for D#2, with the value dial on 0, and then put it in range mode for A4 with the value dial on 1?

Also, I'm not quite clear on the act of calibrating it. From the manual, "Then press and hold the Function knob until it flashes, whilst holding the value knob," what does "whilst holding the value knob" mean? Does it mean that I should press and hold it as well?

I've tried doing this correctly, but I end up with a different calibration than what the manual says should happen: "When course = 9, fine = 0, range = red, etc...the output will be A4 - 440Hz." Well, for me the output was about 890Hz. When I moved coarse to 6, the output was closer to 440, but it was actually quite sharp, and I had no way to fine tune it down because the fine knob was at 0 already.

So I'm concerned about the process for calibrating, and I'm a little concerned that even if I do the process right, the oscitron will still be pitched too sharp.

If anyone could help me with this (please Paul!), that would be awesome. Thanks.

Re: pitch calibration question

« Reply #1 on: February 28, 2017, 08:10:05 PM »
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paulsoulsby

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Ah yes, it's complex.  I think I should do a video to show the process!  It'll be the easiest way.  Can you wait a day or 2 and I'll post a link with the process.

I'll list the process below too, but I think the video will clear things up.

Tutorial Video: https://youtu.be/s6l-9iKFtDo

Tune Freq V/Oct Input
1)  Connect the V/Oct source (e.g. MIDI to CV converter) to Freq 1V/Oct input
2)  Turn function knob to Coarse Freq
3)  Turn value knob to 0
4)  Input 1.25V into Freq input.  Using a Doepfer A-190-2, this is an Oct 3 E flat.  However I am aware that different modules use different voltage offsets. Message me if you are unsure about your module.
5)  Press and hold the function knob and value knob until function knob flashes
6)  Turn value knob to 1
7)  Input 3.75V into Freq input.  Using a Doepfer A-190-2, this is an Oct 5 A (natural).
8 )  Press and hold the function knob and value knob until function knob flashes
9)  Turn value knob to 9
10)  If you input an Oct 4 A (natural), this should output 440Hz from the Oscitron.
11)  Repeat if still out of tune.  If still out of tune after 3 attempts, then email info@soulsbysynths.com

Tune Filter Freq V/Oct Input
1)  Connect the V/Oct source (e.g. MIDI to CV converter) to Filter Freq 1V/Oct input
2)  Turn function knob to Coarse Freq
3)  Turn value knob to 2
4)  Input 1.25V into Freq input.  Using a Doepfer A-190-2, this is an Oct 3 E flat.  However I am aware that different modules use different voltage offsets. Message me if you are unsure about your module.
5)  Press and hold the function knob and value knob until function knob flashes
6)  Turn value knob to 3
7)  Input 3.75V into Freq input.  Using a Doepfer A-190-2, this is an Oct 5 A (natural).
8 )  Press and hold the function knob and value knob until function knob flashes
9)  Turn value knob to 9
10)  With the resonance on full, you should hear the filter cutoff track in tune with the oscillator frequency.
« Last Edit: March 02, 2017, 11:42:54 PM by paulsoulsby »

Re: pitch calibration question

« Reply #2 on: February 28, 2017, 08:57:54 PM »
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leafcut7er

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Dude, a video would be great. Just reading through the freq V/Oct input process, I still have two questions. The process says input 1.25 V (Oct 3 E flat) and then 3.75V (Oct 5 A), but the manual says 1.25V is D#2 and 3.75V is A4. Those are all different notes, right? I'm trying to send a midi note from my DAW through a converter, so I want to make sure I'm playing the right notes!

Secondly, between steps 5 and 6, should one press the function knob to return it to Coarse Freq? Because when I do step 5, the function knob goes to Range. Should it be in Range or Coarse Freq when completing steps 6-11?

Thanks Paul!

Re: pitch calibration question

« Reply #3 on: March 01, 2017, 10:14:05 AM »
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paulsoulsby

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Hi,
I think I am correct here and the manual is wrong  :-[  Just checked notes with MIDI Ox and it is def Oct 3 E flat and Oct 5 A natural when using a Doepfer A-190-2 (with default settings). Means I'll have to update the manual for next batch!  Basically with Coarse Pitch set to 9, A 4 on your keyboard should = 440Hz.  If not, then the keyboard is an octave out or MIDI to CV has different offset.  Only just discovering that there are numerous standards for MIDI to CV converter offsets!!

Just updated instructions.  I missed a little bit.  It's hold function and value knob, not just function knob.

 

Re: pitch calibration question

« Reply #4 on: March 02, 2017, 11:45:32 PM »
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paulsoulsby

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Just added tutorial video: https://youtu.be/s6l-9iKFtDo

To confirm a Doepfer A-190-2 by default sets MIDI note 36 = C2 = 0V.  Therefore the notes required for calibration are 51 (Eb oct 3)  and 81 (A oct 5).

A Beat Step Pro requires the  0V MIDI Note setting (in Device Settings) to be set to C1.   

Re: pitch calibration question

« Reply #5 on: March 06, 2017, 05:32:49 PM »
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leafcut7er

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Thank you, Paul! I'll review the video and try it out. Let you know if I fail and have further questions!  ;)

I really appreciate your prompt support in this matter. Have a good one!

Re: pitch calibration question

« Reply #6 on: March 06, 2017, 06:14:08 PM »
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leafcut7er

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Here's what I found working with the tools at my disposal, Paul. I am using a CV.OCD MIDI>CV device from my DAW. CV.OCD is like the beatstep, C1(MIDI 24)=0V. So I sent a D#2(MIDI 39)=1.25V signal for the first calibration, and a A4(MIDI 69)= 3.75V signal for the second. With the function knob on coarse and the value knob on 9, the pitch was A5. the pitch is A4 on a value of 6. I don't know if I was doing something wrong, but at least I can play the oscitron in tune now.

hope this info helps. please let me know if you think i was doing anything wrong in the process listed above. Thanks Paul.

Re: pitch calibration question

« Reply #7 on: March 10, 2017, 06:15:43 PM »
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paulsoulsby

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Hi,
Did you check the voltage with a volt meter, or did you work it out via the CV.OCD manual?  It sounds like there's a discrepancy somewhere and the CV.OCD is an octave out.  Coarse = 9, should def produce 440Hz. 
Can I also check you're using a square or other basic wave on the Osci, not one of the waves with harmonics that can sound like it's an octave up.  Captured waves can also sound like they're an octave up (depending on settings and audio source).
It's not a disaster if it's an octave out anyway.  As you have done, you can use the coarse pitch to correct. It will mean the CV range is only 4 octaves rather than 5 though.

Re: pitch calibration question

« Reply #8 on: March 15, 2017, 05:01:52 PM »
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leafcut7er

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Hey Paul,

I don't have a voltmeter, I worked it out through the CV.OCD manual. Here's what the manual says:

When CV.OCD is sending out a musical pitch CV, it uses a 1 Volt/Octave standard and has a range of 8 Octaves. Middle C (MIDI note 60) is set at 3 volts, so the output range is approximately MIDI note 24 (C1) to 120 (C9)
 C1 (MIDI 24) = 0V
 C2 (MIDI 36) = 1V
 C3 (MIDI 48) = 2V
 C4 (MIDI 60) = 3V
 C5 (MIDI 72) = 4V
 C6 (MIDI 84) = 5V
 C7 (MIDI 96) = 6V
 C8 (MIDI 108) = 7V
 C9 (MIDI 120) = 8V

I worked it out as best I could (I'm no math whiz) from there.

I think I was using the sine wave, the default wave after turning on the system (right?).