Juno 60 chorus

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itoa
KVRian
Topic Starter
513 posts since 3 Sep, 2009 from Poland

Post Fri Aug 11, 2017 5:20 am

Im trying to make my chorus sound similar to this in Roland Juno 60.

Since I have no access to Juno 60, I try things on TAL UNO chorus plugin. When I select I+II mode I see tripled signal on each channel. Dry + 2 separate repeats, all of them are out of phase so its not like L and R signals are mixed. AFAIK Juno chorus has 2 BBD chips, so how its possible? Is emulation wrong, or I missed something?
giq

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WOK
KVRAF
2117 posts since 24 Feb, 2004 from Germany

Post Fri Aug 11, 2017 7:12 am

Dry + Mod1 + Mod2 = 3 Signals.
Mod1 and Mod2 are phase inverted and different speed.

Image
ImageImage

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Chris-S
KVRAF
2703 posts since 10 Nov, 2013 from Germany

Post Fri Aug 11, 2017 7:16 am

Question is if the TAL chorus is accurate simulating the Roland chorus.

Anyway, when I set stereo offset to zero in TAL chorus LX the extra waves are in sync between L and R.

"I" gives a slow modulated extra wave and "II" a fast modulated extra wave.

itoa
KVRian
Topic Starter
513 posts since 3 Sep, 2009 from Poland

Post Fri Aug 11, 2017 7:23 am

WOK wrote:Dry + Mod1 + Mod2 = 3 Signals.
Mod1 and Mod2 are phase inverted and different speed.
Its not the point...

There are 2 repeats on channel L and another 2 on channel R. Its like there are 4 BBD lines driven by 2 LFOs = ensemble.

Dry = a short pulse wave
Screenshot 2017-08-11 17.31.12.png
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giq

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WOK
KVRAF
2117 posts since 24 Feb, 2004 from Germany

Post Fri Aug 11, 2017 7:59 am

The juno has definitely 2 BBDs, modulated from one LFO producing two phase inverted triangles.
Better have a look for some sound samples from the original device to analyze them.
ImageImage

cyberheater
KVRian
545 posts since 29 Jan, 2004

Post Wed Aug 16, 2017 6:48 am

I came across this that might help.
In The Juno 6 manual ( which might be easier to read), the Chorus LFO output is given as...

I = 20Vpp @ 0.4Hz Triangle
II = 20Vpp @ 0.6Hz Triangle
I+II = 2.6Vpp @ 8Hz Sine (low pass filtered triangle)

So I & II are Chorale triangle sweeps and I+II is a shallower Vibrato sweep.
These 3 LFO types are the only differences between the modes I can see.
Also check out this analysis.

https://github.com/pendragon-andyh/Juno ... ter/Chorus

HoRNet
KVRist
279 posts since 18 Feb, 2011 from Italy

Post Sat Aug 19, 2017 8:38 am

It's been quite some time now and I'm not sure to remember correctly, but when I did the schematic analysis for our Chorus60 I've seen that I+II put the LFO in the same phase increases the frequency and drastically reduces the amount of modulation amplitude.

Saverio

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Richard_Synapse
KVRian
1099 posts since 20 Dec, 2010

Post Tue Aug 22, 2017 1:00 am

itoa wrote:Im trying to make my chorus sound similar to this in Roland Juno 60.

Since I have no access to Juno 60, I try things on TAL UNO chorus plugin. When I select I+II mode I see tripled signal on each channel. Dry + 2 separate repeats, all of them are out of phase so its not like L and R signals are mixed. AFAIK Juno chorus has 2 BBD chips, so how its possible? Is emulation wrong, or I missed something?
If you just want a similar sound, you could take the samples from the link posted above and simply do the same. With the pulse waves, it is particularly easy to see what is going on, and since the chorus has no knobs you have no parameter dependencies to worry about.

Now if you want the exact J-60 Chorus sound you will need the hardware though. From my experience all famous BBD-based chorus/flanger/ensemble units produce perceptually relevant artifacts on top of the basic modulated delay line.

Richard
Synapse Audio Software - www.synapse-audio.com

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WOK
KVRAF
2117 posts since 24 Feb, 2004 from Germany

Post Tue Aug 22, 2017 3:46 am

I think the analysis has some mistakes (and the sound example I+II sounds like the unit is damaged?)
HoRNet wrote: It's been quite some time now and I'm not sure to remember correctly, but when I did the schematic analysis for our Chorus60 I've seen that I+II put the LFO in the same phase increases the frequency and drastically reduces the amount of modulation amplitude.
From the schematics above I can't see that the phase invertion can be bypassed?
Increasing the LFO frequency though indeed needs to fairly lower the modulation amount. I think the hand written values on the schematics are wrong (or maybe "1 sec" at "I+II" must be ".1 sec"?)
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