Silly pitch

Discussion and support for MOTU's Volta software.

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worker8
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Silly pitch

Post by worker8 » Sat Jan 16, 2010 9:43 pm

I'm new to Volta and wonder why the calibration process is so unpredictable.

Now, I tend to calibrate with a louder signal. And I can play easily through 3 octaves.

Is this the only thing I missed ?

I use a MOTU Ultralite mkIII, and play with ZO, A-143-9 & A-110.

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1nput0utput
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Post by 1nput0utput » Wed Jan 20, 2010 3:40 pm

Are you sure that you're not clipping the audio interface input that you're using for calibration? If I recall correctly, all of the UltraLite mk3's inputs have a trim control. A strong signal is good for calibration, but it will be distorted if it's too strong.

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Post by worker8 » Wed Jan 20, 2010 6:11 pm

1nput0utput wrote:Are you sure that you're not clipping the audio interface input that you're using for calibration? If I recall correctly, all of the UltraLite mk3's inputs have a trim control. A strong signal is good for calibration, but it will be distorted if it's too strong.
I don't notice any clipping : I always have an open scope to monitor the incoming signal. Furthermore, my recordings are clean.
:despair:

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1nput0utput
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Post by 1nput0utput » Thu Jan 21, 2010 11:29 am

According to the Volta manual, the UltraLite mk3 analog outputs 1 through 8 produce ±3.5 VDC, which should correspond with about 3.5 octaves from a V/octave oscillator. The main outputs produce ±4.6 VDC, so try using one of the main outputs instead. You should get another octave of pitch CV tracking.

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os
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Post by os » Thu Jan 21, 2010 12:10 pm

±3.5 V is a 7 V range i.e. 7 octaves. I speak from experience.

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Post by worker8 » Fri Jan 22, 2010 7:51 am

os wrote:±3.5 V is a 7 V range i.e. 7 octaves. I speak from experience.
Don't you need a +3,5V offset to feed the VCO with a 0-7V voltage ?

I need to check the input range of my VCOs ...

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os
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Post by os » Fri Jan 22, 2010 7:55 am

That would depend on your VCOs. Most that I'm aware of take both positive and negative voltages. Possibly Buchlas take positive only, though I may be making that up. :razz:

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Post by doctorvague » Sun Jan 24, 2010 9:52 am

os wrote:That would depend on your VCOs. Most that I'm aware of take both positive and negative voltages. Possibly Buchlas take positive only, though I may be making that up. :razz:
I agree, the examples I've seen where only a positive voltage would work was with the MS-20 and a couple of other vintage monosynths (Roland SH-xx for example don't recall which one). Maybe with the Buchla as an exception, I think most modern modular oscillators will accept negative CV's. Otherwise you couldn't even do simple vibrato or frequency sweep with a standard LFO>osc.

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