Confused by Nord Rack 2X

[ephemere]

Okay, this is probably a really basic question. I just got a Nord Rack 2X and am confused about something. When I select one of the preset patches and then alter it by adjusting a SINGLE control, sometimes it seems to pick up other controls, but not all of them. For example, I was playing some factory patch where UNISON was not set. Then I hit the UNISON button. It turned on UNISON (I could hear it clearly), but it also picked up the envelope release knob. The present had a very steep release (sound cut off almost instantly), but when I hit UNISON it picked up the position of the release knob which was a very long release.

So, my question. This is not how I would expect the unit to operate. I would expect that if I twiddle ONE knob/switch, it will change JUST that one setting.

What am I missing here???

[Wout Blommers]

ephemere

It shouldn't set the Release time and it would also be the first time something like this is reported... And the synth is about 16 years on the market...

Beware!!!
Unison uses voices. This means your NL2X has 20 voices (using only one Slot, because the other two would take a voice each, resulting in 5 voices per Slot at the lowest), but Unsison is deviding this by two, so only 10 voices.

You are using rather long Releases, you wrote, so (as said above using one Slot only) you are able to play 10 different notes. Playing the eleventh one will silence the first one (when not pressed, because the NL2X has lowest note priotity and assuming you played that one first the seco0nd one will be silenced), but your setting has very long Release time and will be shut off...

This effect will occure sooner when using other Slots (10 voices devided by two also results in 5 voices)

Will this answer the question?

To learn about the effect:
Set only Slot A active (press all 4 Slot buttons and only one LED will blink and set this to A) Press Shift+Arp=HOLD] Every key you play will sound, even when released. Activate Unison. Play 10 keys: all is right. Play number eleven and the first one is gone...

Wout

[Wout Blommers]

[Wout Blommers]

Okay...

A little test.
You wrote after using Unison the parameter of the Release copied the real setting of the knob?
Change the Release time to completely nothing.
Upload the preset from the memory.
What happens?
If it changes drastically, press [Shift+LFO1 waveform] Set the Release time (move it a litlle] What do you see in the LCD screen?
Is the value stable?

Wout

[Wout Blommers]

Again a new post...

When the value isn't stable, e.g. it switches between 100<>99), the potmeter of the release knob has to be replaced. Any good service station can do the knob. You bought the synth second hand?

The Gain and the Release parameter are nearby the power supply, which becomes rather hot, well known in every Nord. Instability in the potmeter will change the sound. Having an immediate function the parameter will jump to the real position. The instable value will only differ one step besides the knob value, so that is hardly noticed.

But this problem is not related to the use of Unison.

Wout

[ephemere]

Interesting. Thanks so much for the replies.

Somehow, I expect operator error (me) rather than a defective Nord Rack 2X. This is a brand new unit, just out of the box.

My guess is that it's not an unstable pot because as far as I can tell I can play a preset for a long time and it never spontaneously changes. I think I've even left the Rack powered up for hours and come back to it and the voice has not changed to my ears. It only changes when I fiddle with a control. But when I do fiddle with a control, it often changes in unexpected (to me) ways. I gave an example of the unison button affecting release time, but it has happened in other ways, too, quite often. I will have to do more controlled experiments and see if I can get something repeatable that I do not expect, then debug it. I forgot about that way you can see the pot value on the display. That's a good idea!

One interesting thing about the unison-release example is that before that happened, I was playing around with a different preset (call it A) and experimented increasing the release time on it. I then switched to a different preset (call it B) that happened to have a short release, played it for a while, pressed the unison button, and voila got the long release. Was it a coincidence that the only (to my ears) setting patch B picked up happened to be the one I was just before twiddling with patch A? I'm guessing it's not a coincidence, but I don't understand the behavior.

One extra variable in all this is the fact that this is a Rack and not a Lead. The first night I had it out of the box, I was going out of my mind trying to get it to respond to aftertouch. It finally worked after I factory-reset the the keyboard I was using (Kurzweil K2VX), so I conclude that the Kurzweil wasn't sending aftertouch data in the first place for some reason. Incidentally, that's where I first noticed this phenomenon of unexpected voice changing. I'd assign aftertouch mod to a destination, and all of a sudden the sound would be totally different -- presumably picking up positions of various knobs (but hard to tell for certain). I've already learned that if the Rack is in manual mode (awesome feature!), and I power-cycle the Kurzweil, my meticulously created Nord sound is destroyed -- my theory is the Kurzweil sends a patch-change command on power-up and takes the Rack out of manual mode.

I also haven't been able to get the Rack to pick up patches I upload from my computer. But there I suspect it's by bargain basement ($5) USB-MIDI adapter. I need to get a more reliable adapter to test that.

I'll do more experiments.... Thanks again!

[Wout Blommers]

[ephemere]

Okay, I think it is indeed unstable pot(s), even though it is brand new. I took the Kurzweil controller out of the equation, using only the TRIGGER button instead. I used the [SHIFT+LFO1 waveform] function. Does it always show the value of the last parameter changed? So if, say, 5 pots are unstable it will spontaneously switch between 5 values as they drift? I know I read about [SHIFT+LFO1 waveform] once, but I can't remember where. Is it the case that with a correctly functioning Nord Rack, I should be able to leave the unit on all day displaying [SHIFT+LFO1 waveform] and the display would never change number? I did see this number changing, and it did at least once cause the sound to spontaneously change (without me touching anything). The LFO1 rate value seems to be the worst culprit.

Wout, what did you mean by:

[Wout Blommers]

Just a quick one...

In normal mode set all the parameters to 0, except one, best to set it to 60 or 70.
Upload the preset and try to figure out if the 60 is unstable.
If not, try another parameter. Better start with the ones you don't trust.
Mostly one or two can become unstable over the years and special near the warm power supply (at the right side of the Panel)

Get as many info about it as possible and return the synth for a substitute.
New, out of the box? There is a waranty, isn't there?

Wout

[Wout Blommers]

[ephemere]

Hi Wout,

I tried your suggestion to set all but one pot to 0. I tried several pots, and each one had the exact same behavior. Most settings were stable, but if I tried carefully to set it to a position "between" two numbers, then when I press a button it changes from X ==> X+1 ==> X. The X ==> X+1 transition always happens exactly on a button press, but the X+1 ==> X might happen either [1] very soon even before I release the button, [2] right when I release the button even if I hold the button for a long time, or [3] some seconds after I release the button. The A/B/C/D buttons are really good at eliciting this behavior, but other buttons often work, too -- hence my original observation when the UNISON button picked up the RELEASE amount.

This can't be right. Otherwise you couldn't reliably make button-driven sound tweaks during performance. So back the synth goes.

It's interesting, though. It feels like it's not a problem with any subset of pots, but rather it's some systemic problem. Almost as if pressing any button causes a power fluctuation that has the equivalent behavior of nudging all the pots back and forth a miniscule amount, causing each of them to flip-flop value with some probability. This also explains why, once I have a sound loaded in, it remains stable while I play from the keyboard.

I find it curious that there doesn't seem to be a report of this kind of behavior before -- and as you say, the basic design is 16 years old!

Wout, thanks so very much for your help. I can confidently send this synth back now.

[Wout Blommers]

So if I understand you well you are trying to set the pot between two values. I never work that precise
The strange thing is as soon as you use a button the setting becomes instable. This is deadly because of the immediate function. Could be the power supply.
I would contact Clavia about this using the feedback option on there support page on their site. Also link to this thread.

Wout

[ephemere]

No, I wasn't actually trying to set the pot between values. I simply noticed using your experiment that any pot I tried would sometimes have the problem and sometimes wouldn't. I could just as well turn it at random and have it show the same behavior. For some settings of a pot, it would very consistently exhibit the +1 => -1 behavior every time a button was pressed. For other settings, it would be more stable. But since every pot is doing this, the probability that at least one of them somewhere on the board will jump to a value is high. This completely explains all the strange behavior I was noticing with the Nord Rack since receiving it 2 weeks ago. Very often (actually the majority of the time) the sound would change in unexpected ways when I pressed a button, and now I understand what's going on.

[Wout Blommers]

[ephemere]

I'm actually relieved it is defective because I really didn't like the way it was operating! I kept scratching my head thinking, "now why does it sound like THAT?"

I also did check that the power supply is the correct voltage/frequency for my country (USA).

The dealer requires confirmation from Clavia, so I'll send Clavia this thread as you suggest.

In the meantime, I can at least play a preset without any instability by setting all the pots to 0.

Thanks again, Wout, for all your help!

[Wout Blommers]

What I think goes on…
The Lead is digital, but the potmeters are analogue. The potmeter voltages are grouped into ranges who are converted into a digital value. When the analogue value is near the limit at either end of the range, a small voltage change would slip the digital into one value higher or lower. An over all drop of the voltage caused by the power supply is a possibility, specially when more than one parameter shows the problem. If it is just one or two parameters these pots are bad.
I don’t know, but I can imagine using a button could also result in a drop into the voltage. The immediate function would be drastic when there is much differences between the real values and the uploaded ones.

Wout
(BTW I'm used to get the last word