Tal J-8

[zvenx]

Could you post a screen shot please? I for one am not sure I am completely following you e-crooner.
rsp

[chk071]

Hasn't convinced ED has he.

How are VCO's supposed to stay in phase when you are playing a couple of notes? That doesn't make sense, that's why I wonder why it would be happening on a Jupiter-8.

Unless I completely misunderstood how VCO's are working. I always thought they WERE free-running.

See this is really not against the synth, or against TAL (as you seem to suspect), it's just something which some people rightly scratch their head about.

In my understanding there are options like in DIVA, where you can set them to reset the phase on the next note trigger. (That's the more digital way) Or have them run independently from opening the synth (more like Repro)
I'm not sure if this is possible in Diva to have them running all the time, but at least they're free running when triggered (probably random phase) when the reset phase is off.

There are also options to configure that in Spire: There's free-running (ANA button in the osc section turned on), random phase (ANA button turned off), and fixed phase, when you turn up the phase parameter.

[chk071]

Hasn't convinced ED has he.

How are VCO's supposed to stay in phase when you are playing a couple of notes? That doesn't make sense, that's why I wonder why it would be happening on a Jupiter-8.

Unless I completely misunderstood how VCO's are working. I always thought they WERE free-running.

See this is really not against the synth, or against TAL (as you seem to suspect), it's just something which some people rightly scratch their head about.

Not really claiming it's against TAL, I'm simply just not smart enough to come to my own conclusion on this matter so I hope the heavyweights can sort it out and I can just enjoy the accurate results. The idea of ED taking this up with Patrick in private is a good one IMO

Yeah.

It's really pretty simple though: VCO's phase is free-running, which means that every note you trigger will have a different phase. With 2 VCO's, tuned to exactly the same frequency, every note should sound different, because the different phase causes different timbres, because it cancels stuff out. If it sounds exactly the same on every note in that situation, the phase of the oscillators is fixed (because the cancellation always happens at the same part of the resulting waveform).

Anyway, I won't post on about it. There have been enough explanations, and, it's up to Patrick to decide now whether this behavior is as intended. If it is, I really scratch my head about the Jupiter-8, because, obviously there is stuff going on in the oscillators which I just don't understand then.

[Sinisterbr]

You know, TAL-Mod oscillators themselves have the option to run free or reset phase.

[zvenx]

......
What it seems to all mean is that the Zero Detune is a digital only (that is software) only reality...
So is it he should remove Zero Detune on the software since the Hardware seems to not be able to do that?

That is the behaviour of the modeled Oscillators are indeed correct but that a Detune of Zero that is available on the software is not at all physically possible on the hardware (without sync mode enabled)
rsp

Put another way simply:

The software has a Zero Detune, the hardware doesn't. So if you want to replicate the hardware never use Zero Detune on the software.
rsp

[Funkybot's Evil Twin]

Ignore.

*Me. I meant ignore me. Posted in the wrong thread.

[chk071]

......
What it seems to all mean is that the Zero Detune is a digital only (that is software) only reality...
So is it he should remove Zero Detune on the software since the Hardware seems to not be able to do that?

That is the behaviour of the modeled Oscillators are indeed correct but that a Detune of Zero that is available on the software is not at all physically possible on the hardware (without sync mode enabled)
rsp

Put another way simply:

The software has a Zero Detune, the hardware doesn't. So if you want to replicate the hardware never use Zero Detune on the software.
rsp

It's a great way to figure out if the osc's are free-running though.

[e-crooner]

Could you post a screen shot please? I for one am not sure I am completely following you e-crooner.
rsp

A screenshot is just a photo, so it looks about the same for all three synths (except for the roll-off on the J-8). But, what you don't see on the screenshot is that with the J-8 all those green bars are constantly fluctuating, while with the other two synths they are almost static, i.e. hardly any gain fluctuations as you keep the note pressed.

[zvenx]

@chk071, I tried a test, maybe I am missing something.
I created a track with a simple patch zero detuned no resonance and filter wide open, (empty vessells init patch with detune set to zero)...first single notes then chords.
I then duplicated the patch in Cubendo and put one 180 degrees out of phase and played them back.
If they indeed the osc were not free running I would expect the two tracks to cancel out, no?
They don't at all.
rsp

[kmvegas]

something of note from user CoolColJ on Gearslutz...

I did the JP8a 12bit sound wave samples for him

Don't know how much of it he used to calibrate the sound engine, but I know the higher resonance of my synth, and brighter harder driven sound made him add the resonance/brighteness knobs

The synth was modeled on his cleaner 14bit model

Setting the Tone settings to VCO - about 2, drive 1, and reso to 2.5
reminds me of my synth, but I need to do a side by side comparison.
The filter resonance reaction harmonics is not quite the same though

Earlier in this thread, I saw something along the lines of "unless he modelled a 14 bit Jupiter". Someone else had mentioned leaving J-8 alone for several minutes, then finding it had slowly detuned. Putting this all together, and barring any possible sync related bug, maybe it's working a little more "as intended" than some thought? (Still, a Drift control would be spectacular lol)

[dermage]

@chk071, I tried a test, maybe I am missing something.
I created a track with a simple patch zero detuned no resonance and filter wide open, (empty vessells init patch with detune set to zero)...first single notes then chords.
I then duplicated the patch in Cubendo and put one 180 degrees out of phase and played them back.
If they indeed the osc were not free running I would expect the two tracks to cancel out, no?
They don't at all.
rsp

I think that can't be replicated like that. The OSCs in J-8 are drifting differently, yes. But it's about the initial phase so far I understood that. As mentioned, the DIVA + Repro have drift knobs, which controls this. I guess it's hardcoded in J-8. But the thing discussed is about the initial phase both have, so if they start on the same position at the waveform or if the OSC is constantly running and upon trigger you have a gate/env which activates the flow to the filter. And it's not only that, it's also about triggering the same OSC multiple times, and if the phase is not free running it will always begin at the same point of the phase, so possible at the loudest point of the waveform and thus each trigger sounds the same.

Analog OSCs were always running, that means for Jupiter8 there were 8 OSCs running all the time and upon trigger/gate it would trigger the envelope to send the sound to the filter/Amp regardless of on which position of the waveform the OSC was at. That's the reason why each voice sounded differently, even after triggering the same voice.

[chk071]

@chk071, I tried a test, maybe I am missing something.
I created a track with a simple patch zero detuned no resonance and filter wide open, (empty vessells init patch with detune set to zero)...first single notes then chords.
I then duplicated the patch in Cubendo and put one 180 degrees out of phase and played them back.
If they indeed the osc were not free running I would expect the two tracks to cancel out, no?
They don't at all.
rsp

The issue with your test is that the oscillators WILL run in another phase when you close one instance and open another instance, and dial in the same patch again (what dermage referred to as "initial phase"). So, it will maintain the same phase position when you play the patch, but the osc's will start in another phase when you play another instance. So, no wonder that it doesn't null.

Anyway, I don't really want to go on, because I'm not sure what is happening in the synth exactly. Maybe Patrick can shed some light on things, or "fix" it if it needs fixing. All that I can say is that according to the tests I made, the oscillators are fixed phase when you load up the synth, and on the next instance, they are fixed phase as well, just not in the same phase position. Unless I miss something, which is perfectly possible of course.

[e-crooner]

How is random in a synth emulation even produced? Unlike with current and voltage, I think on a computer random is the result of a calculation

[zvenx]

It would seem odd to be fixed phase but with a random start point for each instance to me.
Anyway enough of this for me too....
Patrick has enough information about the 'issue'/non issue and can comment, fix/keep if indeed it needs fixing.

Except to say one last thing .
Remember the history and timing of the Jupiter 8.
1) It was not an American synth.
2) Back then what we love now as being slightly out was considered not so good at the time.... The aim was perfection.. Hence why even in Oberheim and Prophets etc the older reliable ones were 'improved' but now it is the older ones that have more interest in our digital world.

All of which lead to people selling off those unreliable analog gears cheaply to buy the new Digital DX-7 et al.

The idiosyncrasies we love now, were not as loved back then.
Hope that makes sense.

rsp

[teilo]

Portamento is definitely not fixed as of 1.1.5. It's better, but still not right. It's now more consistent though.

Alternate between two chords with the left and right hand. As long as they don't overlap, you can alternate just fine, and portamento works between the two chords. The moment you play both chords at once, release them, and try to alternate between them again, portamento stops working until you move to different notes. I don't have access to a Jupiter-8, so maybe this is how the hardware works.

No issues in monophonic though.