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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: Sat Jan 16, 2010 5:09 pm Post subject:
interslot bus latency |
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I don't know if this has mentioned before. But while patching this, I ran into tiresome problems, which appeared to be due to the interslot buses having a tiny amount of latency. Testing this by sending an audio signal directly to the output and indirectly via an interslot bus confirmed it beyond doubt.
Just that you know.  |
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alcofribas

Joined: Oct 03, 2008 Posts: 22 Location: Eastern France
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Posted: Sun Jan 17, 2010 8:00 am Post subject:
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Bummer.
At least it mustn't be that obvious a lag since it took you so long to come across it.
Alcofribas |
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Roland Kuit
Joined: Sep 29, 2003 Posts: 1090 Location: The Netherlands/Sweden
Audio files: 8
G2 patch files: 127
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Posted: Sun Jan 17, 2010 8:27 am Post subject:
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i'm not behind my G2 now. tim, maybe we can put a logic delay somewhere? |
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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: Sun Jan 17, 2010 3:44 pm Post subject:
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roland kuit wrote: | i'm not behind my G2 now. tim, maybe we can put a logic delay somewhere? |
Yes there are workarounds. But it's still a bummer. I have just developed a DIY voice allocation scheme (which enables DIY arpeggiators, I've just posted two), which requires the voice and fx areas to "talk to each other" sample-accurately. This didn't work, so I had to slow the keyboard scanning process down accordingly. As far as I can tell, it's 24 samples of latency (@96 kHz). So the keyboard scanner had to be 24x slower, scanning the next key every 24 samples instead of every one . In practice, it is still way fast enough though.
But this was a b*tch to detect! I truly thought I was going insane!
(Same for the sequencers outputting their stuff one controlrate sample too late. I was going nuts over this! Thank you Clavia for keeping me on my toes. Always full of surprises, are we? ) |
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3phase

Joined: Jul 27, 2004 Posts: 1189 Location: Berlin
Audio files: 13
G2 patch files: 141
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Posted: Tue Jan 19, 2010 9:49 pm Post subject:
Re: interslot bus latency |
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tim wrote: | I don't know if this has mentioned before. But while patching this, I ran into tiresome problems, which appeared to be due to the interslot buses having a tiny amount of latency. Testing this by sending an audio signal directly to the output and indirectly via an interslot bus confirmed it beyond doubt.
Just that you know.  |
yep..there is a latency. Once thaugt it might be a bug buts its actually because the interslot conections are in fact a real hardware connection between the dsps... so its unavoidable..
For most tasks this dont represents a problem.. i once had a probleme with event timings but was able to compensate with a delay module so the events in the recieving slot was made a tiny bit later than the ones ariving from the bus... Last edited by 3phase on Tue Jan 19, 2010 9:57 pm; edited 1 time in total |
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3phase

Joined: Jul 27, 2004 Posts: 1189 Location: Berlin
Audio files: 13
G2 patch files: 141
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Posted: Tue Jan 19, 2010 9:51 pm Post subject:
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tim wrote: | roland kuit wrote: | i'm not behind my G2 now. tim, maybe we can put a logic delay somewhere? |
Yes there are workarounds. But it's still a bummer. I have just developed a DIY voice allocation scheme (which enables DIY arpeggiators, I've just posted two), which requires the voice and fx areas to "talk to each other" sample-accurately. This didn't work, so I had to slow the keyboard scanning process down accordingly. As far as I can tell, it's 24 samples of latency (@96 kHz). So the keyboard scanner had to be 24x slower, scanning the next key every 24 samples instead of every one . In practice, it is still way fast enough though.
But this was a b*tch to detect! I truly thought I was going insane!
(Same for the sequencers outputting their stuff one controlrate sample too late. I was going nuts over this! Thank you Clavia for keeping me on my toes. Always full of surprises, are we? ) |
oh man.. you are realy patching crazy stuff when i ever come along unsolvable probems i know who to ask
Its defently too much to ask for.. but would be somehow nice if there once would be a G2 tutorial that explains such hidden facts like the dsp delay or theese whole block of sampleacrate processings youve developed..
thats actually award winning stuff somehow.. its anyway interestig that certain things are just possible with the G2-- its in many hidden ways advanced in relation to the NM1... also the voltage outputs that can access CV/Gate synhs... somehow impossible with the Nm1..
Theese kind of hidden possebilitys are probably not just by accident..
Hope clavia continues with the nord modular series.. Seems that there s no other company on the market able of such deep design .. at least it looks like it most of the time... |
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dorremifasol

Joined: Sep 28, 2006 Posts: 823 Location: Barcelona, Spain
Audio files: 7
G2 patch files: 49
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Posted: Tue Jan 19, 2010 11:47 pm Post subject:
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3phase wrote: | ... also the voltage outputs that can access CV/Gate synhs... somehow impossible with the Nm1.. |
What?? is that possible without a hardware modification??  _________________ Cheers,
Albert |
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3phase

Joined: Jul 27, 2004 Posts: 1189 Location: Berlin
Audio files: 13
G2 patch files: 141
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Posted: Wed Jan 20, 2010 12:47 am Post subject:
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No.. but i did the hardware mod on my Nm1 aswell and there there is no way to achive the desired voltages or scale them wright easyli..while in the G2 you get rid of the output caps and with allmost no scaling effort it just fits...
i really wonder if that is by accident or if some people at clavia was trigering analog modules with theire g2 prototypes from day one...
you have to have the output volume full up thou..
but beside that it works great... with a little more patch effort you can make patches where you can tune every key seperatly.. but the astonishing thing was how well the scaling went allready with just a little add/ and multiplikation math.. especially when you realize how much different the G2 behaves here in relation to the NM1..
I also was able to perfectly get Hs/V korg characteristic for a few octaves..
If they ever do a G3 they should do it with DC enabled outs ..and better have more of them .. i really wouldnt mind to have 8 outs and 6 ins ( for guitars and suround...) |
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Nucleus
Joined: Dec 27, 2012 Posts: 6 Location: Minneapolis, Minnesota
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Posted: Thu Dec 27, 2012 10:06 am Post subject:
nord modular G1 CV out Subject description: voltage doubling circuit |
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Is there a simple control voltage amplifying circuit that would increase the 2.41volts (positive and negative) max signal that I measured before the coupling capacitor up to close to the 5 volts+- signal that would be more friendly with Doepfer modules?
The power supply in the nm1 rack has +5v -5v +3v and +9v. |
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dorremifasol

Joined: Sep 28, 2006 Posts: 823 Location: Barcelona, Spain
Audio files: 7
G2 patch files: 49
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Posted: Thu Dec 27, 2012 12:36 pm Post subject:
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I didn't remember this thread. Now that I have a real modular (Analogue Systems) maybe I'll do the modification myself. Are there any pictures of the process?  _________________ Cheers,
Albert |
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varice

Joined: Dec 29, 2004 Posts: 961 Location: Northeastern shore of Toledo Bend
Audio files: 29
G2 patch files: 54
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Posted: Fri Dec 28, 2012 5:36 pm Post subject:
Re: nord modular G1 CV out Subject description: voltage doubling circuit |
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Nucleus wrote: | Is there a simple control voltage amplifying circuit that would increase the 2.41volts (positive and negative) max signal that I measured before the coupling capacitor up to close to the 5 volts+- signal that would be more friendly with Doepfer modules?
The power supply in the nm1 rack has +5v -5v +3v and +9v. |
Nucleus, to the electro-music.com forum
Yes there is a simple amplifier, an opamp configured as a non-inverting amplifier. You might try searching the net for specific circuit examples, or ask for examples in the DIY forum here at electro-music.com:
http://electro-music.com/forum/forum-112.html
But, it might not be a good idea to try to install such an amp in the NM1 because the power supply voltages are so low (would be much better to have +-12 or 15 volt rails!). You could use an LM324 opamp with the NM1 -5 and +9 power supply rails, but you would run the risk of clipping the -5V CV output.
When I modified my G2X to get a DC CV output signal to control the cutoff of my Moog MF-101 Low Pass Filter, I also ran into the problem of the G2X CV signal being too low. My easy and cheap solution was to modify the CV summing circuit in the MF-101 to increase the sensitivity of the external CV input. If you haven’t seen it already, that is discussed here:
http://electro-music.com/forum/topic-12266.html
So, the easiest and cheapest solution may be to just modify the desired CV inputs of your synth modules.
Or, for an off the shelf (but expensive!) solution, add a Doepfer A-183-3 module for each CV that needs to be amplified.
Good luck and please share with us the results of your work. I also have a NM1 Rack and have thought about doing a DC CV mod of the outputs to control an analog mono synth…  _________________ varice |
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varice

Joined: Dec 29, 2004 Posts: 961 Location: Northeastern shore of Toledo Bend
Audio files: 29
G2 patch files: 54
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Posted: Fri Dec 28, 2012 5:41 pm Post subject:
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dorremifasol wrote: | I didn't remember this thread. Now that I have a real modular (Analogue Systems) maybe I'll do the modification myself. Are there any pictures of the process?  |
Hello Albert,
There are details about how I tapped into my G2X to get the DC CV from the G2 Output 4 here:
http://electro-music.com/forum/topic-12266.html
On page 2 of that topic there is a picture of the main PCB with that tap point marked.
If you have a voltmeter or o’scope it would be easy to find similar tap points for the other three G2 outputs. _________________ varice |
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Nucleus
Joined: Dec 27, 2012 Posts: 6 Location: Minneapolis, Minnesota
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Posted: Sun Dec 30, 2012 3:53 pm Post subject:
nord modular c/v out |
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OK I've been working on the c/v out plan, found some simple opamp circuits on howtobuildarobot.com web site. I was about to order some parts then thought I would check output voltage again and I was able to get 4.78v. I headed to Radio Shack to pick up a couple 1/8" cables with stripped ends and 1/4th watt 470 ohm resistors. The varice mod only took about a half hour. I tried playing the keyboard, not only was it not 1v/octave but the higher up I would play the lower the oscillator would go! The output voltage is inverted! That was a bit mind bending. Once I used the voltage inverter part of the InvLevShift module it sounded better. Maybe this is what 3phase was referring to when he wrote about the NM1 signal not being scalable or useable. I have gotten in the 4+ volt range by inserting an amplifier module and cabling the output to the same channel of 2 separate output modules. I haven't figured out what settings yield 1v/octave yet.
It is exciting being able to control my modular with all these nord virtual modules!
note: These are not instructions for someone to follow and blame me if they blow up something.
Some pictures:
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Soldering to the small solder pad in front of the coupler capacitor was delicate. I tinned the end of the resistor wire with a little drop of solder. |
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Last edited by Nucleus on Sun Dec 30, 2012 11:04 pm; edited 2 times in total |
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dorremifasol

Joined: Sep 28, 2006 Posts: 823 Location: Barcelona, Spain
Audio files: 7
G2 patch files: 49
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Posted: Sun Dec 30, 2012 4:01 pm Post subject:
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varice wrote: | Hello Albert,
There are details about how I tapped into my G2X to get the DC CV from the G2 Output 4 here:
http://electro-music.com/forum/topic-12266.html
On page 2 of that topic there is a picture of the main PCB with that tap point marked.
If you have a voltmeter or o’scope it would be easy to find similar tap points for the other three G2 outputs. |
Thanks Varice! I'm thinking about using the outputs 3 & 4 for CV. I only need a push now  _________________ Cheers,
Albert |
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dorremifasol

Joined: Sep 28, 2006 Posts: 823 Location: Barcelona, Spain
Audio files: 7
G2 patch files: 49
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Posted: Sun Dec 30, 2012 4:02 pm Post subject:
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Great work Nucleus, and thanks for the pictures! _________________ Cheers,
Albert |
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Nucleus
Joined: Dec 27, 2012 Posts: 6 Location: Minneapolis, Minnesota
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Posted: Mon Dec 31, 2012 9:23 am Post subject:
nord modular c/v out |
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I made a patch with 1v/octave and gate output. All these years the NM1 was a basket case (no midi note or c/v output). Now it has nine yes nine octaves of c/v and gate output: -4.4v to -3.409v to -2.394v to -1.379v to -.364v to +.65v to +1.665v to +2.68v to +3.68v to +4.65v. When I bought my NM1 in I think 1998 I set it next to the Doepfer modular and wondered how I could interface these two. Thanks to varice and 3phase's posts I finally did it!
Here is a picture of the patch:
and the rest of the patch:
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varice

Joined: Dec 29, 2004 Posts: 961 Location: Northeastern shore of Toledo Bend
Audio files: 29
G2 patch files: 54
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Posted: Tue Jan 01, 2013 4:03 pm Post subject:
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Very nice work Nucleus
Now, have lots of fun driving your Doepfer with your new NM1 CV outputs  _________________ varice |
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varice

Joined: Dec 29, 2004 Posts: 961 Location: Northeastern shore of Toledo Bend
Audio files: 29
G2 patch files: 54
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Posted: Wed Jan 16, 2013 1:29 am Post subject:
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Tim Kleinert wrote: | ...Same for the sequencers outputting their stuff one controlrate sample too late. I was going nuts over this! ... |
Well that explains the problems I have had with a few of my patches. I could tell that the pitch control signal was late compared to the driving clock trigger/gate sometimes. But I found that I could easily get the expected timing corrected by adding a small delay to the trigger/gate signal before any final EG’s or MIDI Note Send modules. With that work around, I never took the time to find out what was actually causing this unexpected problem.
So, with you pointing out that the sequencer modules are the source of this problem, I did some testing. I found that the problem appears to be even worse than you describe: The control signal output appears to be delayed by more than just one control signal rate tick, and also includes the logic trigger/gate outputs.
Other than this issue being mentioned here, I’ve not seen it mentioned anywhere else in the G2 forum. I think that it would be good idea to at least document this problem and suggest workarounds. But not here This thread has already been hijacked beyond all repair (and that’s even partly my fault ). _________________ varice |
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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: Wed Jan 16, 2013 4:41 am Post subject:
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varice wrote: | So, with you pointing out that the sequencer modules are the source of this problem, I did some testing. I found that the problem appears to be even worse than you describe: The control signal output appears to be delayed by more than just one control signal rate tick, and also includes the logic trigger/gate outputs. |
You're probably right. To be honest, I didn't measure the delay precisely, as I was already pretty fed up at this point. BTW, the recording functionality of the note sequencer (blue "Rec" input etc.) is also a minefield of weird delay behaviour.
I stumbled on all this as I was trying to build a non-volatile RAM circuit with fast access times around cascaded note sequencers. (Part of a self-calibrating physical modelling patch, which I then shelved.) |
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varice

Joined: Dec 29, 2004 Posts: 961 Location: Northeastern shore of Toledo Bend
Audio files: 29
G2 patch files: 54
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Posted: Fri Jan 18, 2013 5:49 pm Post subject:
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varice wrote: | Tim Kleinert wrote: | ...Same for the sequencers outputting their stuff one controlrate sample too late. I was going nuts over this! ... | ...Other than this issue being mentioned here, I’ve not seen it mentioned anywhere else in the G2 forum. I think that it would be good idea to at least document this problem and suggest workarounds. But not here ... |
Done Posted in the Bug forum (although I suspect that this problem may not be a bug, but possibly intentional instead... ):
http://electro-music.com/forum/topic-56557.html _________________ varice |
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