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ian-s
Joined: Apr 01, 2004 Posts: 2669 Location: Auckland, New Zealand
Audio files: 42
G2 patch files: 626
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Posted: Mon Mar 05, 2007 9:21 pm Post subject:
Alpha Juno DCO |
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I never owned any DCO synth, I didn't like the sound when they first came out.
Anyhow, I have been playing with tracking comb filters for alias free wave shaping and was trying to get one of the Juno Saw AM'ed Pulse variations SAW 02/03 in the manual.
The diagram shows a double frequency rectangle wave whose upper edge tracks the shape of a sawtooth over 2 periods.
I patched this using a unipolar copy of the master Sawtooth AMing the double frequency rectangle, assuming that this would sound identical to the wave as illustrated.
Just in case, I also patched a version that duplicated the wave shape exactly by shifting both inputs to the LevMult to unipolar then converting the result to bipolar.
There is a significant difference in tone, one has more pronounced even harmonics. Problem is, I don't know if the diagram in the manual is a stylised representation of the wave or strictly accurate.
Does anyone know what a real, unfiltered, alpha juno SAW 02 looks like on a scope or wave editor?
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Unipolar, like the manual |
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3phase
Joined: Jul 27, 2004 Posts: 1183 Location: Berlin
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Fozzie
Joined: Jun 04, 2004 Posts: 875 Location: Near Wageningen, the Netherlands
Audio files: 8
G2 patch files: 49
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Posted: Tue Mar 06, 2007 5:14 am Post subject:
Re: Alpha Juno DCO |
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g2ian wrote: | Does anyone know what a real, unfiltered, alpha juno SAW 02 looks like on a scope or wave editor? |
If you'd settle for a jx10 as well, I could make a pic. Hopefully I'll have time for it tonight.
BTW: intriguing avatar, G2ian. A homage-in-disguise to Talking Heads - talking pants?
edit: read it too quickly. I guess the JX is no good for lack of AM (and you're really after a specific alphajuno patch). Sorry. _________________ Spinning at ~0.0000115740740741 Hz |
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dasz
Joined: Oct 16, 2004 Posts: 1644 Location: victoria, canada
Audio files: 29
G2 patch files: 56
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Posted: Tue Mar 06, 2007 8:35 am Post subject:
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I think this avatar is from Dr Seuss... That drawing style is instantly recognizable ...
I totally invented my avatar and take full creative credit for it
/Dasz |
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Fozzie
Joined: Jun 04, 2004 Posts: 875 Location: Near Wageningen, the Netherlands
Audio files: 8
G2 patch files: 49
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Posted: Tue Mar 06, 2007 8:53 am Post subject:
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dasz wrote: | I think this avatar is from Dr Seuss... That drawing style is instantly recognizable ...
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Ah, I see now. I was a bit scared at first 'cause I didn't know what it was
(OK I googled) _________________ Spinning at ~0.0000115740740741 Hz |
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JohnC
Joined: Mar 18, 2007 Posts: 1 Location: Washington DC
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Posted: Sun Mar 18, 2007 2:40 pm Post subject:
Alpha Juno Sawtooth |
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The Alpha Juno uses a half-sine wave instead of a true sawtooth. The diagram in the Roland manual is incorrect.
Are you thinking "Hoover?" |
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peterw
Joined: Jan 10, 2007 Posts: 18 Location: This Small Island
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Posted: Mon Mar 19, 2007 1:59 pm Post subject:
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My Alpha Juno 2 unfiltered PWM saw looks very much like your unipolar scope picture.
It is unipolar but looks a lot cleaner.
Sorry I cannot post a picture as I do not have a digital camera. |
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Jason
Joined: Aug 12, 2004 Posts: 466 Location: Los Angeles, CA. USA
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Posted: Tue Mar 20, 2007 11:11 am Post subject:
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I have an alpha juno.
Would it be helpful to post a pic of its waveforms?
I would be happy to do so. |
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ian-s
Joined: Apr 01, 2004 Posts: 2669 Location: Auckland, New Zealand
Audio files: 42
G2 patch files: 626
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Posted: Tue Mar 20, 2007 11:36 am Post subject:
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Please do.
Unfiltered DCO Sawtooth wave 1,2,4 and 5 would be great. |
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Jason
Joined: Aug 12, 2004 Posts: 466 Location: Los Angeles, CA. USA
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Posted: Wed Mar 21, 2007 9:36 am Post subject:
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what is a good oscilloscope app? any specifics on what I should set it to? |
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Jason
Joined: Aug 12, 2004 Posts: 466 Location: Los Angeles, CA. USA
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Posted: Wed Mar 21, 2007 9:52 am Post subject:
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this is using Nuendo's internal oscilloscope. Is this sufficient?
Oh yes and it is an Alpha Juno2. I also have an MKS-50 which is closer to an alpha juno 1 though they are all quite similar, let me know which is most helpful. I can do the rest once I know I am getting the info you want. |
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ian-s
Joined: Apr 01, 2004 Posts: 2669 Location: Auckland, New Zealand
Audio files: 42
G2 patch files: 626
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Posted: Wed Mar 21, 2007 10:06 am Post subject:
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Hey that is perfect thanks. It looks like a quarter sine
Sawtooth 2,4 and 5 would be good (3 is just like 2 with variable width).
Maybe one square to make sure it is actually square
Ta very much.
PS Does that unit have the 'what the' preset? Any chance of a short and simple one or two note mp3? |
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Jason
Joined: Aug 12, 2004 Posts: 466 Location: Los Angeles, CA. USA
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Posted: Wed Mar 21, 2007 11:21 am Post subject:
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Sorry my previous post was inaccurate. My compressor was in the signal path and I wasnt thinking. So here is a cleaner version of the waveforms. My apologies. Next is "What The" |
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Jason
Joined: Aug 12, 2004 Posts: 466 Location: Los Angeles, CA. USA
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Posted: Wed Mar 21, 2007 11:54 am Post subject:
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Alpha Juno 2 preset "What The"
I didnt edit this , if it is not at factory default someone else did , but I doubt it. |
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iPassenger
Joined: Jan 27, 2007 Posts: 1067 Location: Sheffield, UK
Audio files: 5
G2 patch files: 78
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ian-s
Joined: Apr 01, 2004 Posts: 2669 Location: Auckland, New Zealand
Audio files: 42
G2 patch files: 626
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Posted: Wed Mar 21, 2007 12:38 pm Post subject:
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Thanks Jason.
The curved back of the sawtooth and sloping top/bottom of the square look like the result of a DC block somewhere in the signal path. It might be in the synth itself but, despite the waves looking quite different on the scope to the ideal shape, it is not that significant to the sound.
A 6dB high pass at the lowest frequency setting gives the same distortions. Come to think of it, that is probably what is happening in the Juno, it has a high pass filter which is never completely off
Thanks again |
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Jason
Joined: Aug 12, 2004 Posts: 466 Location: Los Angeles, CA. USA
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Posted: Wed Mar 21, 2007 1:08 pm Post subject:
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yes I tried a different input on my soundcard as I was still not going direct and got better results. I thought bypassing the compressor would be enough for this but I was wrong, obviously adding anything in the path was a mistake. I tested plugging directly in and the waveforms are different I can post those if needed.
This DC block you speak of, can you elaborate a bit for me? |
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ian-s
Joined: Apr 01, 2004 Posts: 2669 Location: Auckland, New Zealand
Audio files: 42
G2 patch files: 626
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Posted: Wed Mar 21, 2007 2:48 pm Post subject:
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Jason wrote: | This DC block you speak of, can you elaborate a bit for me? |
It is usually just a capacitor in series to block DC from the input. It is like a very low frequency high pass filter. The idea is to pass AC (audio) and stop DC (constant voltages).
I'm guessing that the new shots just look a little less curvy? |
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Jason
Joined: Aug 12, 2004 Posts: 466 Location: Los Angeles, CA. USA
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Posted: Wed Mar 21, 2007 4:16 pm Post subject:
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Yes here is one of the pulse1 waveform again. Yes just a bit less curvy.
Thanks |
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ian-s
Joined: Apr 01, 2004 Posts: 2669 Location: Auckland, New Zealand
Audio files: 42
G2 patch files: 626
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iPassenger
Joined: Jan 27, 2007 Posts: 1067 Location: Sheffield, UK
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Posted: Fri Mar 23, 2007 11:01 am Post subject:
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regarding this DC block malarky, i sampled the outputs on my nord with a software OSC and got similar looking results (square/pules waves) to those above. Is this normal. E.g. it isn't really square is it?
Also I sampled my waldorf pulse too n that is really curved, not very square at all at the extremes.
Cheers
R. _________________ iP (Ross)
- http://ipassenger.bandcamp.com
- http://soundcloud.com/ipassenger |
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Jason
Joined: Aug 12, 2004 Posts: 466 Location: Los Angeles, CA. USA
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Posted: Sat Mar 24, 2007 1:00 pm Post subject:
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right on g2ian.
Thanks for the patch, I can hear some similar aspects indeed.
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