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Tim Kleinert
Joined: Mar 12, 2004 Posts: 1148 Location: Zürich, Switzerland
Audio files: 7
G2 patch files: 236
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Posted: Fri Mar 26, 2004 4:22 am Post subject:
Interfacing the G2 with analog gear |
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Hi my friends; I have a question someone might be able to answer.
The G2 offers line inputs for audio signal processing. I wondered: can those also be used as CV inputs, to input control signals from analog synths?
I'm unfortunately pretty ignorant when it comes to electronic specifics, so I'm not sure if audio line signals and CV signals are 100% compatible.
Actually, what I intend to do is to implement a Yamaha Breath Controller in a direct way, rather than having it running through a breath-to-MIDI convertor (which reduces the resolution to a mere 127 steps and always has a small latency).
(To turn the inputted CV signal into a blue control signal, one then could use the envelope follower module with fast env times.)
The Breath Controller input wants to see 0 to -10V at the ring of a stereo input plug. The tip is the sourced -10V. The closer this voltage is to -10V the greater the volume/modulation.
Somebody told me that one would have to build a small inverter/attenuator, with a 9V battery as power source.
What are the specs of the G2 inputs? Any experience with this? ...and how big is the risk of busting the ADCs in the process ?
Sorry, this is (analogly speaking) probably a hoplessly newbie-ish question.
Anyway -all comments welcome.
regards,
tim |
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egw
Stream Operator
Joined: Feb 01, 2003 Posts: 1569 Location: Asheville NC
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Posted: Fri Mar 26, 2004 5:29 am Post subject:
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You might have better luck with the control pedal input. |
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Tim Kleinert
Joined: Mar 12, 2004 Posts: 1148 Location: Zürich, Switzerland
Audio files: 7
G2 patch files: 236
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Posted: Fri Mar 26, 2004 5:45 am Post subject:
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Quote: | You might have better luck with the control pedal input. |
I thought about that.
However -interfacing various CVs from an analog modular with the G2 via the line inputs is an interesting subject in itself, IMO. I'm interested in the possibility of this application. |
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mosc
Site Admin
Joined: Jan 31, 2003 Posts: 18197 Location: Durham, NC
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Posted: Fri Mar 26, 2004 8:27 am Post subject:
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I don't know the answer to that, yet. Most audio inputs on electronic equipment is AC coupled. This means they run the input through a capacitor and that eliminated the DC component. In the case of a CV, the DC component is what you want. I'll go over an post this question on the NM list. Maybe someone there knows. |
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mosc
Site Admin
Joined: Jan 31, 2003 Posts: 18197 Location: Durham, NC
Audio files: 212
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Posted: Fri Mar 26, 2004 11:17 am Post subject:
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I posted your question on the NM list and got this response from Rob. Looks like Greg was right. It is doable.
Rob Hordijk wrote: | No CV to an audio input, they are AC coupled. But, I have a lot of fun with
a Doepfer Theremin module connected to the G2 Expression Pedal input. Works
like a charm!
I use a simple 6.3mm mono jack with sleeve to earth and tip to the analog
CV.
The Pedal input accepts voltages between 0 and +5 V. But a proper Pedal
input is protected to negative and overvoltages, as just by accident
anything can be plugged in and it should survive. 220 is of course asking
too much. But the Pedal inputs of both the NM and the G2 accept LFO and CV
signals from ± 15V analog systems. I don't know if this is actually in the
official specs, but I used these signals and the synths survived. I also use
a Theremin module on a Roland GX-700 guitars effect processor Pedal input,
and that is lots of fun as well.
So, yes. The G2 has one single CV input, the Pedal input. Plus one input for
a gate, the Sustain input. I never tried the sustain input, so from my side
no warranty it will work.
And for CV out, well, what worked for me is a PW modulated pulse from a NM
audio output that goes into an analog envelope follower module. But for the
G2 there is of course the MIDI CC# out modules that will work with any
proper Midi->CV box.
/Rob |
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Tim Kleinert
Joined: Mar 12, 2004 Posts: 1148 Location: Zürich, Switzerland
Audio files: 7
G2 patch files: 236
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Posted: Fri Mar 26, 2004 5:08 pm Post subject:
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mosc- thanks again for checking things out for me!
So if I get Rob correctly, the pedal input should be able to handle the breath controller, which ranges from 0V to -10V. Of course, I have to check if the jack connections (TRS) are the same.
Hope this works. |
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mosc
Site Admin
Joined: Jan 31, 2003 Posts: 18197 Location: Durham, NC
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Posted: Fri Mar 26, 2004 8:36 pm Post subject:
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You know, it's interesting about Rob's Thereman which produces a CV. I have one that is only audio out, but It works great with the G2's the envelope follower and pitch tracker.. |
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Rob
Joined: Mar 29, 2004 Posts: 580 Location: The Hague/Netherlands/EC
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Posted: Mon Mar 29, 2004 8:41 am Post subject:
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[quote="shoshin"]mosc- thanks again for checking things out for me!
So if I get Rob correctly, the pedal input should be able to handle the breath controller, which ranges from 0V to -10V. Of course, I have to check if the jack connections (TRS) are the same.
Hope this works.[/quote]
Hi,
The Yamaha breathcontroller cannot be used directly, as the G2 Pedal input accepts a 0V to +5V signal. So, it would only read a 0 value. Also, the BC3 needs 12V power. A little bit of electronics with a 12V adapter would be required. I'm planning to have a little box developed, as I would like to connect a BC3. And there is some other people that would like to have such a 'BC2G2' converter box. When this happens I will post about it. _________________ /Rob |
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seraph
Editor
Joined: Jun 21, 2003 Posts: 12398 Location: Firenze, Italy
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Posted: Mon Mar 29, 2004 10:29 am Post subject:
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Rob wrote: | there is some other people that would like to have such a 'BC2G2' converter box. |
do you know of any midi to breath controller adapter besides the one by "midi solutions"?
I would like to use my breath controller BC3 with not-yamaha keyboards _________________ homepage - blog - forum - youtube
Quote: | Don't die with your music still in you - Wayne Dyer |
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Posted: Mon Mar 29, 2004 11:07 am Post subject:
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seraph wrote: | Rob wrote: | there is some other people that would like to have such a 'BC2G2' converter box. |
do you know of any midi to breath controller adapter besides the one by "midi solutions"?
I would like to use my breath controller BC3 with not-yamaha keyboards |
The only one I know of is the controllerbox that comes with the Kurzweil ExpressionMate ribbon. This controllerbox can be used without the ribbon attached, but its a bit an expensive solution as 50 cents worth of electronics should be able to do the job. I remember it was dead simple. Somewhere in the 'shoebox archives' there must be a little note on the schematics. Please don't blame me if it takes a little time to dig it up... |
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Tim Kleinert
Joined: Mar 12, 2004 Posts: 1148 Location: Zürich, Switzerland
Audio files: 7
G2 patch files: 236
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Posted: Mon Mar 29, 2004 3:35 pm Post subject:
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Quote: | Hi,
The Yamaha breathcontroller cannot be used directly, as the G2 Pedal input accepts a 0V to +5V signal. So, it would only read a 0 value. Also, the BC3 needs 12V power. A little bit of electronics with a 12V adapter would be required. I'm planning to have a little box developed, as I would like to connect a BC3. And there is some other people that would like to have such a 'BC2G2' converter box. When this happens I will post about it.
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I've been waiting for such a device for a long time. BC causes too much MIDI traffic when using a BC-to-MIDI-convertor, so having it this way would be fantastic. Please keep me posted on this! Thanks. |
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Tim Kleinert
Joined: Mar 12, 2004 Posts: 1148 Location: Zürich, Switzerland
Audio files: 7
G2 patch files: 236
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Posted: Tue Apr 06, 2004 3:05 pm Post subject:
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I've just found out that one of my students at the conservatory had previously studied electronic engineering.
Converting CVs to line inputs ain't hard, he says.
A four-channel CV-to-line converter (maybe with attenuators) for the G2 would be a good idea to start a small business -if one had the time
I'll get a BC-to-line converter built for myself soon. nothing like having a 24/96 BC signal. |
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mosc
Site Admin
Joined: Jan 31, 2003 Posts: 18197 Location: Durham, NC
Audio files: 212
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Posted: Wed Apr 07, 2004 9:09 am Post subject:
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HeHe... No wonder he switched to music.
Tell your student that the G2's inputs are AC coupled. CVs are DC signals, they won't work with the G2 inputs, no matter what he does to scale them.
If you want more than the control pedal input, use a CV to MIDI converter. |
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blue hell
Site Admin
Joined: Apr 03, 2004 Posts: 24079 Location: The Netherlands, Enschede
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Posted: Wed Apr 07, 2004 11:10 am Post subject:
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mosc wrote: | HeHe... No wonder he switched to music.
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Well actually, Howard, the guy is right ... It's not too hard ... and you could know so more or less as just a few posts earlier you almost gave the solution yourself.
Convert the CV signal into AC by applying it as AM modulation on some AC signal of not too low a frequency. Then use the envelope follower etc. in the G2 just the way as you described before in your Theremin mail.
Jan. |
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mosc
Site Admin
Joined: Jan 31, 2003 Posts: 18197 Location: Durham, NC
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Posted: Wed Apr 07, 2004 2:07 pm Post subject:
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Well, yes, that will work. It is complicated but it will work. I think CV to MIDI is more generally useful
Yesterday a friend brought a Bass over to the studio. We plugged it into the G2's audio input. It turns out that the G2's envelope and pitch followers are really excellent. I was quite impressed. We were able to put together a patch that tracked the bass very well enabling the use of a Bass as a mono synth controller.
This fellow has a big bunch of pedals hooked up in a processing chain including Moog filter, Phase shifter, some kind of Base synth module, delay, reverb, and octave divider. In about 15 minutes we proved that a G2 can replace all of that, and you'd have 3 slots left over for synths, percussion sequencers, and whatever.
A very pleasant surprise was the G2's Frequency Shifter Module which I tried out for the first time. This is virtually a Bode Frequency Shifter. Moog used to make these in the late 60s and 70s. It was very expensive and highly coveted. It's like a ring modulator, which gives both the upper and lower side bands (sum and difference frequencies), but it also provides just the sum or just the difference. It's very clean, no feedthrough like the original Bode shifter had. Since it is digital, it is always in perfect trim. You can, of course mix in the carrier, add some hum and hiss and get that authentic Bode sound.
For the price of one of these beasts on Ebay, you can get a new G2!.
| Original Bode Frequency Shifter
| Analogue Systems Bode Frequency Shifter Copy
| G2 Frequency Shifter
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Tim Kleinert
Joined: Mar 12, 2004 Posts: 1148 Location: Zürich, Switzerland
Audio files: 7
G2 patch files: 236
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Posted: Thu Apr 08, 2004 2:36 am Post subject:
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Quote: | Convert the CV signal into AC by applying it as AM modulation on some AC signal of not too low a frequency. Then use the envelope follower etc. in the G2 |
Exactly.
Quote: | I think CV to MIDI is more generally useful |
The problem with converting Breath Control to MIDI and using this 127-step-resolution control signal is that this signal has a lot of jitter in it (unlike a Foot Controller signal). The steppyness of this jitter often causes some kind of subtle noise in certain kinds of patches. Of course you can apply smoothing to it -but that inadvertently makes the response sluggish. (Added to that is the small latency from the standalone MIDI-to-BC convertor.)
I don't know how good the response of the G2 envelope follower is -but I find the possibility of obtaining a 24kHz/24bit breath control signal most promising, and will therefore sooner or later bully my student into this DIY-project
However -I'll first have to wait until the G2X hits our country (I've changed my order). Until then, it's still preparatory study study study... |
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Tim Kleinert
Joined: Mar 12, 2004 Posts: 1148 Location: Zürich, Switzerland
Audio files: 7
G2 patch files: 236
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Posted: Thu Apr 08, 2004 2:39 am Post subject:
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...oh and I forgot to mention the very high MIDI traffic caused by BC. Some synths can't even handle it. |
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mosc
Site Admin
Joined: Jan 31, 2003 Posts: 18197 Location: Durham, NC
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Posted: Thu Apr 08, 2004 7:12 am Post subject:
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OK, I'll be interested to see how this works out.
BTW, you can alway go back and edit a post.
128 steps is a major problem sometimes. The G2 knobs have that problem. Most of the time it's not annoying or limiting, but sometimes, like when you use them to control the frequency of an oscillator over a very wide range, the limited quantization is exasperating. The ION uses high resolution encoders which are much nicer.
What kinds of parameters are you planning to control with a breath controller where the 128 step quantization will get you that smoothing wouldn't cure? Just curious. |
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Tim Kleinert
Joined: Mar 12, 2004 Posts: 1148 Location: Zürich, Switzerland
Audio files: 7
G2 patch files: 236
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Posted: Thu Apr 08, 2004 2:37 pm Post subject:
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Quote: | BTW, you can alway go back and edit a post. |
Yeah -I remembered that afterwards. Sorry . I also post on other forums, where this isn't possible.
Quote: | What kinds of parameters are you planning to control with a breath controller where the 128 step quantization will get you that smoothing wouldn't cure? Just curious. |
I used BC in conjunction with the morph function of the NordLead3 (routing it to aftertouch), and found that some parameters were prone to producing subtle background noise when modulated with this "jittery" MIDI control signal. These were especially the parameters that dealt with distortion (in the osc or in the filter sections), or anything else that considerably affected the amplitude of the patch.
Smoothing them would sure work, but make the response more sluggish and therefore less ideal for real-time performance.
But actually, I don't know yet what I will use BC for on the G2, since the G2 has so much more to offer. I've been diving heavily into physical modeling and waveguide synthesis concepts, and hope to apply much of it to the G2. The BC will be part of the whole madness. |
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