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Adjusting 2 slew gens with one knob?
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Author Adjusting 2 slew gens with one knob?
Rex Coil 7
Ok, this is a weird one.

Imagine ......

2 slew generators (let's say two Q105 types) ... each one has it's own "amount" control. Set one to "UP", the other to "DOWN". Use each one's ~amount~ control to set separate levels of UP slew and separate levels of DOWN slew. All of this for a single 1v/oct signal. That said, I would guess the two slew gens would have to be in series.

With me so far?

Ok, now the tricky part. What must be done to adjust both of them at the same time, using one control, without upsetting their relative settings?

Sortof like how an audio mixer can be used to set relative signal levels with individual channel faders, then set the master volume with the master volume control without changing the relative mix of the two independent channels.

How would one go about doing that, but with Slew Gens? And is there a way to get that done using the Q105 as a foundation to start with? Per normal, I am fully willing to repanel this oddball rig.

Told you it was a weird one, even for MY stuff!

w00t
josaka
seriously, i just don't get it
Rex Coil 7
josaka wrote:
not that odd.. smile just split the CV via a mixer(an ivertable one would be better Q114/oakley multimix.). send the CV to the mixer and use a splitter cable to the cv of your slews.. send the signal via a VCA to get automation..
I completely do not understand this.

Even though I can't wrap my head fully around your explanation, the way I'm trying to view it in my head seems as though the use of the VCA will mess up the 1v/oct scaling really badly. Remember, this is slewing for 1v/oct "keyboard" signals, used as portamento. The control signal that has been slew limited needs to retain it's accurate scaling, using a VCA to change the slew amount will screw up that scaling.

So, when you're saying "split the CV via mixer" do you actually mean to say use a distributor to split the CV signal? Er ... ?

hmmm.....

I'm not following. Sorry. seriously, i just don't get it
Thalassa
The only way that I can think of for doing what you want is with a concentric potentiometer were you could set the controls to for slew up and down and after that lock the potentiometer and when you turn it , it will turn both internal potentiometer at the same time. But I don't know if such potentiometer exists .....
Synthbuilder
If I understand this correctly and both slews are always going to be in series then could it not be done with one Oakley VRG? Set the Up and Down controls to the needed timings and send a control voltage which is derived from a single pot to the UP CV input. The UP CV and DOWN CV pots controlling the sensitivity of said CV input.

Tony
Rex Coil 7
Synthbuilder wrote:
If I understand this correctly and both slews are always going to be in series then could it not be done with one Oakley VRG? Set the Up and Down controls to the needed timings and send a control voltage which is derived from a single pot to the UP CV input. The UP CV and DOWN CV pots controlling the sensitivity of said CV input.

Tony
I took a look/see. Seems viable. Only thing I saw that throws me is the expo mode does the opposite thing I would want (going fast at first, then slowing as the signal gets closer to the note ... I'd want it to move slower at first, then speed up towards the note held down ... like a jump ramp instead of a hill).

I'll look at it again when I get up, it's a little past 2am here.

Thanks Tony.
Rex Coil 7
Thalassa wrote:
The only way that I can think of for doing what you want is with a concentric potentiometer were you could set the controls to for slew up and down and after that lock the potentiometer and when you turn it , it will turn both internal potentiometer at the same time. But I don't know if such potentiometer exists .....
But if one is set differently than the other (which is the whole point of this thing) one will stop while the other still has range left.
Gizmo
Synthbuilder wrote:
If I understand this correctly and both slews are always going to be in series then could it not be done with one Oakley VRG? Set the Up and Down controls to the needed timings and send a control voltage which is derived from a single pot to the UP CV input. The UP CV and DOWN CV pots controlling the sensitivity of said CV input.


Echoing Tony: If what you want to do can be simply described as “voltage controlled portamento” then a single Oakley VRG is easily capable of this. I have two and use them frequently for this purpose, settings as shown.



Rex Coil 7 wrote:
Only thing I saw that throws me is the expo mode does the opposite thing I would want (going fast at first, then slowing as the signal gets closer to the note ... I'd want it to move slower at first, then speed up towards the note held down ... like a jump ramp instead of a hill).


Your response curve requirement is puzzling. Is this really what you are after:

Rex Coil 7
Gizmo wrote:
Synthbuilder wrote:
If I understand this correctly and both slews are always going to be in series then could it not be done with one Oakley VRG? Set the Up and Down controls to the needed timings and send a control voltage which is derived from a single pot to the UP CV input. The UP CV and DOWN CV pots controlling the sensitivity of said CV input.


Echoing Tony: If what you want to do can be simply described as “voltage controlled portamento” then a single Oakley VRG is easily capable of this. I have two and use them frequently for this purpose, settings as shown.

Good, that's the whole reason this forum exists, to create a forum of discussion to expose people to things they don't know about, and wouldn't otherwise gain that exposure. In short, the forum has performed it's intended purpose in this case.

Gizmo wrote:
Rex Coil 7 wrote:
Only thing I saw that throws me is the expo mode does the opposite thing I would want (going fast at first, then slowing as the signal gets closer to the note ... I'd want it to move slower at first, then speed up towards the note held down ... like a jump ramp instead of a hill).


Your response curve requirement is puzzling. Is this really what you are after:

Yes, my Kurzweil PC3A6 uses a curve like that, I've also made glide curves like that with a MATHS 2013. I like the way it sounds. Why is that puzzling?

As an example of it's use, refer to videos of people that really know how to use the "glide knob" on a Moog modular keyboard controller (the one that has the glide knob at the left end of the 61 note controller). Often times they'll turn the Glide control towards faster glide times as the note swings upward. Effectively making the glide slow at the beginning and faster near the end. It's a very common little technique during live performance. I've used it myself countless times.

I suppose I can just use an envelope gen to control the VC Slew unit's time. I've done that with the MATHS a number of times, works fine. Add Velocity into an EG output level VCA to control the EG's emphasis on the slew limiter, and you end up with Velocity controlled portamento.

Done it, it's fun. thumbs up

Now that I am aware of the Oakley VRG, I'll have to think this over. I'm not what you might call very "Oakley aware", I've never owned any of Tony's gear, and I haven't made it a priority to familiarize myself with his entire catalog. A person can't be expected to know all things about all things. So I'm really glad that I authored this thread. I've become aware of something that was otherwise unknown to me, and I'll make it a point to look deeper in to a few other makers. I've been slowly learning about 5U offerings other than Synthesizers.Com as I move forward in designing pieces of a project synth. I am especially interested in modules that can be either disassembled to use the PCBs in repanels and/or 15v compatible kit systems for the same reason.

cool
Lostintime
You may find this thread interesting: https://www.muffwiggler.com/forum/viewtopic.php?t=178529&start=0&postd ays=0&postorder=asc&highlight=

It discusses conversion of MATHS to other formats as well as the DIY Befaco Rampage (a Eurorack dual slew limiter that can be bought as PCB and has schematics available).
ranix
This patch initially defeated me but I think I've figured out a solution.

Check this out (I am kind of proud of it). Wouldn't have been able to come up with it without Josaka's post which he unfortunately deleted. Commit to your stupidity man! You are only human, together we will find the truth

Use two slew limiters, we will refer to them as Lesser Slew Limiter and Greater Slew Limiter where Greater slews more than Lesser (longer transition time is set on Greater).

Control CV -> Lesser Slew Limiter input
Lesser Slew Limiter output -> Multiple
Multiple output -> Greater Slew Limiter input
Multiple output -> CGS62 Slope Detector input
Multiple output -> Q962 Signal input 1
CGS62 RISE output -> Q962 Trigger input 1
CGS62 FALL output -> Q962 Trigger input 2
Greater Slew Limiter Output -> Q962 Signal input 2
Q962 output -> VCA Exp. FM input

If glitches are experienced, patch the Greater Slew Limiter output to the CGS62 Slope Detector instead of the Lesser Slew Limiter.

As for modulating the slew amount, I am stumped on that part. A slew limiter is really just a low pass filter - I think - so maybe you could use a filter in place of a slew limiter for voltage control?

I need more filters, been using filters like crazy lately. I'm really thinking about getting like 6 Q107A but Never maintain cash savings again
josaka
Quote:
Wouldn't have been able to come up with it without Josaka's post which he unfortunately deleted. Commit to your stupidity man! You are only human, together we will find the truth


I have zero problem with my stupidity .. the reply was poor so I decided to delete any further help.. but this idea sounds like the deep note(actually beaver and Krause idea(which was ignored)
no idea what sound he is going for at all.. so there is that.. the deep note was done in that way I think.. I posted a challenge thread a while back to see if folk could do it in modular.. there were a few bumpy attempts..smile .. but as a general thing .. if someone is trying to help.. being a tit is not great..
ranix
it was a good post thx for the patch idea
josaka
this was one of the videos that show it.. I did it using two .com slews
Rex Coil 7
josaka wrote:
... no idea what sound he is going for at all.. so there is that..
This is about the best I can offer. I sketched this out to provide a visual reference to help explain what I wish to do. I want to be able to set an up rate, and a down rate (perhaps differently from one another) which is what any number of "2 channel" slew generators can do, such as the Dual Bissell. The problem is that to turn them collectively up or down, you must turn two knobs at once ... accurately ... during live performance. With a sortof "master" control, different up and down slew rates may be adjusted, and a single control can be used to turn the whole thing up or down, collectively, without disturbing the up/down rates that were so carefully set up.

As I keep referring to, the idea is just like the way an audio mixer operates. Each input channel can have it's own individual signal level set by it's own channel fader. But there is a set of "L/R" master faders that turn up/down the entire relative mix of all of the individual channels without disturbing their individual levels.

Apply the same concept to two slew generators. One controls up times/rates, the other controls down times/rates. Then there would be a master up/down controller that would adjust the "mix" of the up/down rates without disturbing the up/down relative rates.

This is the best I can do as far as explaining myself. I really do wish I had access to better words to convey the idea. Perhaps a better phrase to use for the "master" control would be "master gain"? Hmmm ... maybe not .... that may just cloud the issue even further.

Well, this will have to suffice. "Tony" (Oakley) got it. The only hitch with the VRG is, as explained, the exponential curve is reverse of how I want the response to affect the portamento.

I've been working with a well known Miffwugglers member (who, quite frankly, is ten light years beyond my capability), he's working on a solution, and he gets the idea. I am just trying to come up with something myself, as I like to be challenged. I know I can do it with the MATHS, as I have already done it. Preferred expo curve and all. But I just wanted to run it past the 5U Jedi masters here to look for alternatives.

The Befaco unit sounds possible. I'll have a look.



josaka wrote:
but as a general thing .. if someone is trying to help.. being a tit is not great..
Surely you're not saying that I was being a "tit" in my reply? Actually, I thought I was being quite nice. I'm hoping that I am just misunderstanding your statement I've quoted here. Most internet cross-ups are due to simple misunderstandings. At least that's been my experience.

Perhaps you and I need to talk about this via PM?

nodnod
Rex Coil 7
josaka wrote:
this was one of the videos that show it.. I did it using two .com slews
Mmmm ... close. But I think it's different somehow.
Rex Coil 7
Lostintime wrote:
You may find this thread interesting: https://www.muffwiggler.com/forum/viewtopic.php?t=178529&start=0&postd ays=0&postorder=asc&highlight=

It discusses conversion of MATHS to other formats as well as the DIY Befaco Rampage (a Eurorack dual slew limiter that can be bought as PCB and has schematics available).
Now THIS seems appealing. Read through it once, saving it to really comprehend the content. The ~look~ matches what I've done with my own 5U project, nearly spot on.

It wouldn't take much to adapt what Member *mmeixner has done to fit within the ethos and style I've created. As I've heard/read the Befaco Rampage is very close to the MATHS regarding capability and function. As I've said, I already know .. for sure .. MATHS will cover what I want to achieve. The Rampage seems to contain all of the necessary components and capabilities I'd need to get there. Perhaps use a joystick to adjust the up/down controls as X/Y functions.

seriously, i just don't get it

Normalize a few functions to suit my system, add it to a pair of Q123 Standards modules to complete the 1v/oct performance controls ... do a few little changes, panel everything on a 2U tall 19 inch wide rack panel ... call it done.

(He said). meh lol lol

(May be a good idea to contact *mmeixner regarding the purchase of the Front Panel Designer file .... everyone's time is worth something ... I would at least offer.)

mmeixner wrote:
.... I bought a befaco rampage kit, which works with +-15V without problems, and am just now in the process of converting:



I can report about resistors I'll change maybe.




Thank you very much, *Lostintime. This may help!

thumbs up
ranix
I think the important part was the bit about combining two slew limiters, then thinking about what you can do with the various signals you then have access to. josaka said that you feed them to a mixer in the beaver & krause patch. That got me thinking about trying to use a Q111 pan/fade to combine two slew limiters and be able to switch between them.

But then it's hard to get the CV signal to control the slew limiter to respond differently to "notes going up" than "notes going down". The CGS62 was the solution I found, because if you feed a slew limited keyboard CV to it, it will detect a transition and very briefly pulse either the RISE or FALL signals depending on whether the CV is ascending or descending.

It was harder to convert the trigger signal from the CGS62 to be sustained to work the pan/fade than it was to just patch the triggers directly to a sequential switch.
josaka
as far as I can tell.. this is exactly what you are trying to do..
according to your diagram at least.. sliding between to two set notes using portamento(your version only has speed differences?) .. you can control the rate via the mix knob(as seen in the video above) which is what I was talking about using an automated mixer via a VCA ...

to get separate times and rates would only involve more offset modules(lfo/adsr/VCA) and would become quite melodically erratic.

much better off using seperate voices for that.. and about 100x easier.

the basic technique of two opposite sliding portamento controls between 2 notes is exactly what I put in my original post.. and what these people are doing.. and exactly what Beaver and Krause did in the 70s..
ranix
I think Rex is asking about a monophonic patch where the slew on notes played in an ascending fashion is different than the slew on notes played in a descending fashion. Such that if you play a note, then one semitone higher the slew rate may be faster than if you were to play a note then one semitone lower.

Additionally I think he wants to have one control that can simultaneously alter the slew rates of both the ascent and descent slew.
Rex Coil 7
ranix wrote:
This patch initially defeated me but I think I've figured out a solution.

Check this out (I am kind of proud of it). Wouldn't have been able to come up with it without Josaka's post which he unfortunately deleted. Commit to your stupidity man! You are only human, together we will find the truth

Use two slew limiters, we will refer to them as Lesser Slew Limiter and Greater Slew Limiter where Greater slews more than Lesser (longer transition time is set on Greater).

Control CV -> Lesser Slew Limiter input
Lesser Slew Limiter output -> Multiple
Multiple output -> Greater Slew Limiter input
Multiple output -> CGS62 Slope Detector input
Multiple output -> Q962 Signal input 1
CGS62 RISE output -> Q962 Trigger input 1
CGS62 FALL output -> Q962 Trigger input 2
Greater Slew Limiter Output -> Q962 Signal input 2
Q962 output -> VCA Exp. FM input

If glitches are experienced, patch the Greater Slew Limiter output to the CGS62 Slope Detector instead of the Lesser Slew Limiter.
Yea man! The coffee was really kicking in for that one! lol

It would probably work, however not for my needs. It seems like one hella neato setup as I machete my way through the jungle of thought it creates. Nice going!

ranix wrote:
As for modulating the slew amount ..... maybe you could use a filter in place of a slew limiter for voltage control?
Y'know .... I've considered that a number of times. Used Q107s can be had for less than the cost of a new slew generator (well, almost). But may as well go with the Oakley VRG at that point. Hmm .. maybe not, the possibilities of using a state variable VCF as a slew unit are very intriguing.

ranix wrote:
I'm really thinking about getting like 6 Q107A but Never maintain cash savings again
With a fekking FLAMETHROWER!! lol
josaka
ranix wrote:
then thinking about what you can do with the various signals you then have access to.

yes..

ranix wrote:
josaka said that you feed them to a mixer in the beaver & krause patch. That got me thinking about trying to use a Q111 pan/fade to combine two slew limiters and be able to switch between them.

But then it's hard to get the CV signal to control the slew limiter to respond differently to "notes going up" than "notes going down". The CGS62 was the solution I found, because if you feed a slew limited keyboard CV to it, it will detect a transition and very briefly pulse either the RISE or FALL signals depending on whether the CV is ascending or descending.
.

the main fundamuntal problem for all these different speed ideas are the musical problems ..mostly it is going to sound fucking horrible !! smile I spent ages messing with this idea .. unless you get the notes to end on a musical or harmonic "note" it just sounds like kaka.. the CV part is one thing.. getting something decent is another.. I did get some great sounds doing these tests.. but it was a bit of pot luck.. having said that the journey was fun and ultimately satisfying..
Rex Coil 7
ranix wrote:
I think Rex is asking about a monophonic patch where the slew on notes played in an ascending fashion is different than the slew on notes played in a descending fashion.

Such that if you play a note, then one semitone higher the slew rate may be faster than if you were to play a note then one semitone lower.

Additionally I think he wants to have one control that can simultaneously alter the slew rates of both the ascent and descent slew.
SOMEONE BUY THIS MAN A BEER!!!!!!!!!!!

Chugging Beers

SLAM-BANG-RIGHT-ON-THE-HEAD-OF-THE-NAIL PERFECT EXPLANATION!!!!! thumbs up

IN ONLY THREE. FOOKING. SENTENCES. NO LESS!!!!!!
we're not worthy

Thanks TRUCKLOADS *ranix .... I'm glad someone was able to more eloquently relay my thoughts.

Whew wee .... I can breathe now. This subject was stressing me out for some reason. I was beginning to feel thick.

nodnod spinning
josaka
ranix wrote:
I think Rex is asking about a monophonic patch where the slew on notes played in an ascending fashion is different than the slew on notes played in a descending fashion. Such that if you play a note, then one semitone higher the slew rate may be faster than if you were to play a note then one semitone lower.

you need an offset to do this.. possible but a nightmare. (two synched lfo?)
a variation on the B&K idea..


ranix wrote:
Additionally I think he wants to have one control that can simultaneously alter the slew rates of both the ascent and descent slew.

well the B&K patch does exactly this but if you want separate speeds there are a load of ways to do that just add in a controllable cv offset or 2.

two voices .. so.. much.. easier.
josaka
I may even try my two synched LFO idea.. sounds like it could be mental..



@ Ranix if you want another filter look at the Moon 917s or for the SVF look at the Oakley.. smile

some sounds of the SVF
http://oakleysound.co.uk/svf.htm
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