Korg Poly800/EX800 Users

Hi Poly fans,

Well, it's just been way too quiet around this list lately so let me
whet your appetites with some even more interesting news.

I've hacked 90% of the code for the LFO. I expect that I'll have a
second LFO operating within a few more weeks.

I've worked out how the LFO is retriggered on each key hit so we can
make that a user selectable option to disable the retrigger. Plus,
we'll have an option on the second LFO to allow it to simply free run.

I've almost worked out the mathematics of the LFO saw tooth so we can
now change that to include square wave and possibly ramp with
selectable inversion. I'll work on the square wave first. The only
limitation I can find in the existing design is that if we slow the
LFO down a lot then we are probably going to hear the DtoA stepping,
especially on the VCF with higher resonance settings.

At this point, the only limitation is that the second LFO will be set
up in the global parameters section and will apply to all patches. The
reason for this is that I am going to have to completely rewrite the
patch editing/copying etc code to allow additional parameters and that
is going to take quite a bit of work. So I would rather get the new
LFO features out there and then go back and rework the patch management.

Enjoy!

Mike.

----- Original Message -----

From: korgpolyex800

To: korgpolyex@yahoogroups.com

Sent: Monday, November 19, 2007 11:07 AM

Subject: [korgpolyex] LFO update

Hi Poly fans,

Well, it's just been way too quiet around this list lately so let me
whet your appetites with some even more interesting news.

I've hacked 90% of the code for the LFO. I expect that I'll have a
second LFO operating within a few more weeks.

I've worked out how the LFO is retriggered on each key hit so we can
make that a user selectable option to disable the retrigger. Plus,
we'll have an option on the second LFO to allow it to simply free run.

I've almost worked out the mathematics of the LFO saw tooth so we can
now change that to include square wave and possibly ramp with
selectable inversion. I'll work on the square wave first. The only
limitation I can find in the existing design is that if we slow the
LFO down a lot then we are probably going to hear the DtoA stepping,
especially on the VCF with higher resonance settings.

At this point, the only limitation is that the second LFO will be set
up in the global parameters section and will apply to all patches. The
reason for this is that I am going to have to completely rewrite the
patch editing/copying etc code to allow additional parameters and that
is going to take quite a bit of work. So I would rather get the new
LFO features out there and then go back and rework the patch management.

Enjoy!

Mike.

Yes! We shall have it! By random LFO, do you mean a random modulator?

Mike.


--- In korgpolyex@yahoogroups.com, Neil Wakeling <neil@...> wrote:

>
> Sounds marvelous, Mike.
> 
> Hmmm - could we have a random sample and hold LFO?
> 
> Best Wishes with the project,
> neil
> 
> 
> korgpolyex800 wrote:
> >
> > Hi Poly fans,
> >
> > Well, it's just been way too quiet around this list lately so let me
> > whet your appetites with some even more interesting news.
> >
>

Yes, last night I successfully added two new global parameters that
allow you to select square wave for DCO and or VCF instead of the
existing sawtooth.

The DCO LFO in square wave mode shifts the DCO by a half note
(semitone) so although it's good to have it didn't blow my mind. I
have to do a bit more work on that.

The VCF LFO in square wave mode didn't do a great deal for me either
until I added a minimum and maximum depth value for it. Now the square
can be set to sit wherever you want it to in the VCF range. The result
was definitely mind blowing. And the sound provided by a square wave
definitely gives alot of the sounds a new cranky edge to them.
Especially at slower rates. And the VCF responds quite well to the LFO
in square wave mode, so you don't hear too much ramping between high
and low. It is detectable but only slightly.

At the moment, the LFO runs twice as fast as it should for the square
wave. That's something I'll fix over the next couple of days.

And at 11PM, I ran out of brain power to add in the random MG. But I
should be able to get that going soon for the VCF. I don't think I'll
be able to put the random MG onto the DCO very easily because the full
range of the MG is only one note. But the VCF should be ready soon.

This is fun!

Mike.

Be a better pen pal. Text or chat with friends inside Yahoo! Mail. See how.

On Mon, 19 Nov 2007, Neil Wakeling wrote:

> Hmmm - could we have a random sample and hold LFO?
=================

one nice thing about the kawai K3 was the LFO had a mode that's like 
random, but the levels of output corresponded to a 12 note scale. i think 
they called it "chromatic random". would that be feasible?

i'm curious how you're implementing a "random" LFO in the poly800...? is 
there enough CPU power to do a PRNG, or is it based on a look-up table? 
how long is the cycle?


-- 
         ...atom

  ________________________
  http://atom.smasher.org/
  762A 3B98 A3C3 96C9 C6B7 582A B88D 52E4 D9F5 7808
  -------------------------------------------------

 	"Growth for the sake of growth is
 	 the ideology of the cancer cell."
 		-- Edward Abbey

Hi all,

I implemented a LFO random for the VCF. Though, my pseudo random
number generator is not great. I'll have to find a better one but it
works. I've also implemented it with depth control using parameter 84.
I like the sound of doing a chromatic randomise. I'll have to think
about how to implement that though. The problem right now is that the
LFO applied to the DCO only shifts the frequency up or down ONE
semitone. So the LFO really doesn't push the DCO frequency much at
all. That's why I've not bothered to do the random on it at this
point. So when I develop the second LFO, I will write code to support
pushing the DCO frequency across a wide range. We know the hardware
can do it because the joystick is able to flex the DCO a full octave.

; my pseudo random number generator - used for the LFO randomiser

RANDOMIZE:	lxi	h, M_RANDOM
		mov	a, m
		cpi	0
		jnz	RANDOMIZEA
		cma
		mov	m, a
RANDOMIZEA:	rlc
		adi	43
		mov	m, a
		ret

Mike.

--- In korgpolyex@yahoogroups.com, Atom Smasher <atom@...> wrote:
>
> On Mon, 19 Nov 2007, Neil Wakeling wrote:
> 
> > Hmmm - could we have a random sample and hold LFO?
> =================
> 
> one nice thing about the kawai K3 was the LFO had a mode that's like 
> random, but the levels of output corresponded to a 12 note scale. i
think 
> they called it "chromatic random". would that be feasible?
> 
> i'm curious how you're implementing a "random" LFO in the
poly800...? is 

> there enough CPU power to do a PRNG, or is it based on a look-up table? 
> how long is the cycle?
> 
> 
> -- 
>          ...atom
> 
>   ________________________
>   http://atom.smasher.org/
>   762A 3B98 A3C3 96C9 C6B7 582A B88D 52E4 D9F5 7808
>   -------------------------------------------------
> 
>  	"Growth for the sake of growth is
>  	 the ideology of the cancer cell."
>  		-- Edward Abbey
>

Yep, that's right. I have a new youtube video of the Poly 800 with TWO
LFO's working. Check it out at http://youtube.com/watch?v=IApgQHrwL0o

Thanks to ALL of YOU who provided direct input into the LFO. I would
not have thought it possible to get the second LFO working so fast but
you all gave me the inspiration I needed to get it done.

I've duplicated the original LFO and split them so that the original
LFO applies to the DCO and the second one applies to the VCF.

You can select triangle or square waves for the DCO LFO1. You can
select triangle, square or random for the VCF LFO2. For the square
wave, you can set the high and low offset from center on both LFO's.
You can also set the delay on both LFO's. And you can set both LFO's
to free run (so they don't reset/retrigger on each new note event).
The sweeps you get out of the VCF are beautiful. I think just getting
those continuous VCF sweeps everybody will love their Poly's all over
again. But then the random on the VCF is fantastic too. I think the
moog slayer mod with these two LFO's is going to be a big hit.

I've also finished the keyboard local control on/off. And I've
implemented the MIDI TX channel keyboard send as well. Those by
themselves are great because it makes the Poly more useful as a
controller. I'll be adding a velocity send parameter too so that you
can set the MIDI TX note velocity to whatever you want. I may even
make it somehow proportional to the joystick bend.

My next goal for the LFO part of the world is to implement a super LFO
that will modulate the VCF LFO itself. So that we'll be able to have a
nice super slow modulation of the first modulation to sweep the VCF up
and down while also have the smaller modulated VCF wave in there.

That one could take a while since we'll be modulating the modulator.

But enjoy!

Mike.

Will be there any tutorial howto make second lfo ?? :)

Yes, I will post documents on a web site somewhere. Not sure where
just yet.

The document (or web pages) will provide full details on how to
program the new global and extended parameters as well as all of the
new functions and features that the new Poly 800 MK3 will have.

Mike.

--- In korgpolyex@yahoogroups.com, "radek_tymecki" <radek.tymecki@...>
wrote:

>
> Will be there any tutorial howto make second lfo ?? :)
>

Mike,

I don't know if you answered this, but will the new mk3 be able to 
keep the existing internal patches in memory intact, or will 
reprogramming be necessary?

Erik


--- In korgpolyex@yahoogroups.com, "korgpolyex800" 
<korgpolyex800@...> wrote:

>
> Yes, I will post documents on a web site somewhere. Not sure where
> just yet.
> 
> The document (or web pages) will provide full details on how to
> program the new global and extended parameters as well as all of the
> new functions and features that the new Poly 800 MK3 will have.
> 
> Mike.
> 
> --- In korgpolyex@yahoogroups.com, "radek_tymecki" <radek.tymecki@>
> wrote:
> >
> > Will be there any tutorial howto make second lfo ?? :)
> >
>