That CEM3340 beast from the east. a mouser cart maybe? hows the tuning and calibration going!@!?!
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I’m not sure I’d need a built-in tuner, so I suppose I’ll try building it without the Arduino circuit. If I understand correctly the tuner is just a parasitic circuit that displays the note name from the Ramp Output on a seven segment display, so I can just leave those components off the board and tune the VCO by ear when I feel like it.
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yep! im going to make a smaller none tuner one. its looking like im going to be releasing more than one a month now so it’ll be coming soon, the next is an envelope generator, then 2 different types of VCA. hopefully after it’ll be a MIDI - CV and maybe even the none tuner VCO
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I’m completely on-board with the basic concept of a VCO with an inbuilt tuner. I’m just going to leave that part of the boards unpopulated because the effort of building that part of the design and programming the Arduino won’t get me to where I want to be. The design is still great. I could have just laid out the schematic on veroboard, it’s that clear.
But I want to go with the Kosmo format, at least to begin with. I need to experiment with ways to fit modules together without being too fussy about module footprint. Kosmo is just different enough to accommodate big jacks, and I’ll have fun working out a sustainable way of fixing Kosmo modules into my chosen case. Which is an old bookcase…
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I am wondering what it would take to not only see its out of tune, but actually send a calculated offset voltage to automatically tune it.
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i was thinking the same thing. a feedback buffer of some sort? hmm perhaps an anti drift cct like in radio’s ?..hmm
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yeah definitely It did cross my mind an auto tune circuit. even a button and input that does it so it doesn’t fudge up the lfo and stuff I dunno
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In the tuner Arduino code, is the frequency variable in some arbitrary unit?
I was expecting to see the 440 for the A concert pitch, but 440 falls in the range defined for F in the code.
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I multiplied hz by 10 to get more resolution in the lower range (4385<frequency && 4480>frequency). you can fiddle and make it more tolerant with the code. but for me I went through the whole tuning register and decided for myself what was a tolerant note. as I have found each note in each octave varies, and I felt the tuning tolerance was down to taste. you’ll notice in the 3rd octave the g and f are actually quite a bit off what is usually quoted, this is just cus it sounds more right in a chord.
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maybe it wasn’t that g and f, I cant remember off the top of my head, I spread it over a few evenings, as I found if I spent too long on it my senses wouldn’t make heads or tails of what was an acceptable note haha. if you look at Jos, GitHub linked at the bottom of the page there is a piece of code with the frequencies in a table if you want to adjust them! in the end of the day Im making all of these to work in my synth and hopefully they will give other people joy too, but it doesn’t mean you cant improve them for yourselves and such. for instance the oscillators work and sound good for my uses at shows and stuff, and the tuner is likewise, I mean I think its setup pretty usefully! who knows 
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hi there, looking forward to receiving my pcb/panel.
one question - have you measured the power consumption of the module? looking for a powersupply/busboard for a few of your modules.
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OK, it makes sense.
You mentioned in a couple of videos that you play mostly in the key of C major, is it possible that you tuned it to use the exact scale of C major instead of the well tempered chromatic scale? (Just a theory, I didn’t look at the numbers closely enough to know and my ear definitely won’t tell me.)
It probably doesn’t matter much anyways, because if the oscillator is calibrated to 1V/oct, once you tune one note, for example middle C, then everything else should follow.
I think, for me, I’ll adjust the tuner code to track the tempered scale as closely as possible as I am still training my ears.
One could argue that the oscillators should be tuned to the 440Hz concert pitch A and exactly 1V/oct, and that any desired de-tuning/micro-tuning should be handled in the MIDI to CV converter.
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luckily I play in A minor and Ab minor so more of the notes are covered. the concert pitch is a fair point, I never really understood why a set point like that made sense. being a musician for 20 years now, I stopped using tuners about 3 years in and just tuned guitars and stuff to where I thought was right. a number of times in my songwriting endeavours I send off the stems from songwriting sessions with artists over to producers and they get annoyed cus its half way between 2 notes as we wrote it beginning on a ear tuned acoustic and keyboard or something. but to me it doesn’t make sense to stick to that, seems like an unnecessary regulation on music in general. I decided to put tuners in here because big rooms blur bass frequencies, a number of times i’ve been caught out not being able to make out what the note is, so I had to go back to tuners haha. hope that makes sense why I dont go for concert pitch.
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Microintervals are a thing :). If it sounds right, it is right!
I just learned all of the modes of C major since it just uses the white keys. Easier for me to intuit and shit. Oh, i want to play minor? A minor it is then.
- Ionian / (Major Scale): C, D, E, F, G, A, B, C.
- Dorian : D, E, F, G, A, B, C, D.
- Phrygian : E, F, G, A, B, C, D, E.
- Lydian : F, G, A, B, C, D, E, F.
- Mixolydian : G, A, B, C, D, E, F, G.
- Aeolian / (Natural minor scale): A, B, C, D, E, F, G, A.
- Locrian : B, C, D, E, F, G, A, B.
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Just for fun, I looked at what Wikipedia has to say about the classical Greek music system. Sadly not much music survives from that era. To be fair, it’s debatable whether much modern (c15
to c21, say) music will be around in 2500 years. At least we can easily build classical Greek instruments and tune them as they did. Will the ability to build something as sophisticated as a violin, a lute, a pipe organ or a MiniMoog survive long, along with the cultural knowledge to make sense of a Bach fugue or a Talking Heads album?
Nevertheless there is a fascination in ancient musical modes. A lot of Western music theory comes from the discovery of harmony and the development of mathematical tools to predict the notes produced by an instrument one has never seen. I haven’t even looked at classical Indian music, though I remember being very happy with the pieces I heard Ravi Shankar perform on an early 1970s album.
There is something beautiful about the human urge to discover order in the frequently chaotic process of making pleasant noises.
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I wouldn’t call it completely unnecessary.
Having a common set point is very useful when instruments that are hard to re-tune on the fly are involved, like pianos, harpsichords, pipe organs, xylophones etc.
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@lookmumnocomputer did you ship ordered modules on friday?
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hey! in December I got a warehouse logistics company that do march posting for a bunch of musicians merch stuff I know, because I kept on making mistakes! so on Thursday I sent the restocks to the warehouse to turn up on Friday, so hopefully they also got posted on Friday too!
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indeed! I agree, but this all came from my piano which I tune by ear too haha, its about 1 and a half semitones too low haha. oh what a nightmare. but you are right, and luckily this tuner works well with that kinda stuff, I have my own tuner code that is about half an octave offset. but I haven’t uploaded that because its probably no use to anyone!
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The 1222 VCO’s outputs all go from 0 to a positive voltage, 0-5V for the triangle, 0-10V for the sawtooth and 0-12V for the pulse.
Typically oscillator outputs are centered around zero and go equally positive and negative.
I think it would be good in a future revision of this VCO to get rid of this DC offset.
Since the outputs are already buffered with opamps, it would just be a matter of adding a few resistors.
They could also be adjusted to all have the same amplitude at the same time.
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