Stacking JD-990s?

[bienpegaito]

I need some help stacking my new 'used' JD-990s.

I've found in the manual where and what the midi settings are for each machine. However I can't find any other info.

If someone is or has done this I'd appreciate some instruction.

Specifically, how do you route the midi between the machines and a PC. Is it PC Midi Out > Master Midi In > Master Midi Out > Slave Midi In > Slave Midi Out > PC Midi In? Also does the 'slave' simply mirror the master as far as patches go and add voices ... or can you set up different patches on the slave to actually 'stack' the patches for each preset?

Any help getting started would be appreciated.

prado

[White]

Are you using multiple JD's?

The master keyboard midi'd to the JD-990 by midi in from the JD going to the midi out on the PC. midi in on the PC going to to the out of the first JD. Then midi thru from the first JD to midi in on the second JD.

I don't know about the rest. Do you simply want to stack voices on one midi channel?. Then it's just a case of setting all the Modules to the same midi channel.

Hope that helps.

[bienpegaito]

Thanks Duncan ...

Yes, trying to run two of them in 'stack' mode ... for which they were designed and have a special midi setting that selects 'Stack' and designates each units order in the stack.

I tried the routing you mentioned (or am pretty sure I did!) and just got this hi pitched low level whine with neither machine responding ... even though they both work perfectly as individual side by side units and work the way you suggest when they are not set internally to 'stack' mode.

Maybe I can get something out of Roland tech support.

prado

[White]

Ah right

Let me revise my reply.

Midi out from the PC to the midi in on the master keyboard, then midi out from your master keyboard to the midi in on your computer.

Then Midi thru from your master keyboard going to the midi in on one of the JD's and midi thru from one JD to the Midi in on the second JD.

Try that.

[cornutt]

Odd, I don't recall the 990 having a MIDI overflow mode, but I could be wrong. I'll look tonight. You can download the manual from rolandus.com (you have to register first, but it's free).

[bienpegaito]

Hi Cornutt ...

Thanks ... I did d/l the manual. For some reason it doesn't seem to accept searches ... maybe some older pdf format ... so I'm left with the Table of Contents and the Topical and Regular Index.

See Appendix page 34 of the Owner's Manual II (Reference) for a description of stack and stack parameters.

So were this 'over flow' would the right set up be midi out from the first unit to midi in of the second unit as opposed to midi thru from the first unit to midi in of the second? And what would that do with the analog outs?

Thanks.

prado

[bienpegaito]

Related question ... if this is only going increase polyphony, but essentially otherwise 'cripple' the second unit as an additional sound source ... i.e., render it as a 'mirror' of the first unit ... maybe I don't want it anyway? I never intended it as a single sound module for all purposes.

So is the correct understanding of 'stack' or midi 'overflow' simply that it increases polyphony but adds no other functional advantages?

prado

[aeon]

This info is all in the Reference Manual, pg. Sys-8. Look up "stack" in the index.

Your MIDI controller sends its OUT to the first JD-990 IN. Connection from that first JD-990 to the next JD-990, and indeed, every other one, up to 8 total, is via THRU to IN.

Yea, this increases polyphony only. A JD-990 has 24 voices/oscs of poly, such that your poly for 1/2/3/4-osc sounds is 24, 12, 8, and 6 voices respectively. Two stacked JD-990s will yield 48, 24, 16, and 12 voices respectively, for a given patch.

You don't have to stack. You can address each JD-990 as its own unit, and still have 24 voices/oscs of poly per unit. This is usually more useful. The stack mode is there when you need to have more than 6, 8, 12, or 24 voices of poly for a 4, 3, 2, or 1-osc patch, respectively.


cheers,
Ian

[bienpegaito]

Hi Aeon!

You nailed it. Thanks for the dope.

But it takes me back to the drawing board ... that is how I tried to 'stack' them when I got that weird whine and nothing else? It seems like just going midi thru (from one) to midi in (to the next) wouldn't sync the patches. That's why I thought in stack it might be midi out (from one) to midi in (to the next). Otherwise you'd just be sending the notes from the keyboard thru and the units wouldn't seem to be communicating. Have to tinker a bit more.

prado

[bienpegaito]

Thanks again Aeon ... found it and you are correct. I still don't see how the patches would sync unless you'd sent a midi/ or sysex message from somewhere up the line. I guess to just mess around with them I'll set the patches manually.

One other thing that I don't get ... how does the second and or third etc. unit know when the first unit has exceeded it's polyphony? I mean if you're playing a big chord with one hand and noodling runs with the other how can it possibly know the moment you exceed?

prado

[aeon]

Thanks again Aeon ... found it and you are correct. I still don't see how the patches would sync unless you'd sent a midi/ or sysex message from somewhere up the line. I guess to just mess around with them I'll set the patches manually.

I'm not sure as I have never had the pleasure of having two (or more!) JD-990s.

My guess is you would have to sync them manually. It would be nice if there was a function to make all the "slaves" be copies of the "master."

One other thing that I don't get ... how does the second and or third etc. unit know when the first unit has exceeded it's polyphony? I mean if you're playing a big chord with one hand and noodling runs with the other how can it possibly know the moment you exceed?

The ones down the line don't need to know - they just wait for note-ons. The first unit plays what it can, and if it gets more note-ons than it has poly, it passes them to the THRU to the next module, which then starts playing. If its poly gets exceeded, it would pass to the next module, if present, and so on - up to 8 modules.


cheers,
Ian