Charts to convert EG and LFO values to "real" valu

Kayemef · Post by **Kayemef** » Fri Feb 12, 2010 12:52 pm

Hi everyone!

I've made 2 charts that translate the intuitive values from EG times and LFO frequency into "real" values.
There's something in the help file that looks more like a really small spreadsheet... I made a big nice graph so that you'll really know how long is a 45 worth on the good old ADSR.

you can find them on rapidshare at this link :

http://rapidshare.com/files/349598302/O ... s.rar.html

Cheers

P.S. : Both have algorithmic scales on the Y... google it if you don't understand

Charlie · Post by **Charlie** » Sat Feb 13, 2010 11:21 am

Hm - this links tell me, that maximum downloads (10) was reached before my request = no download-possibility for me any longer.

Akos Janca · Post by **Akos Janca** » Sun Feb 14, 2010 9:53 am

Unfortunately, same problem here.

Kevin Nolan · Post by **Kevin Nolan** » Sun Feb 14, 2010 5:46 pm

This link seems to be gone completely.

any chance of putting it on korgforums download page for oasys?

Kevin

Kayemef · Post by **Kayemef** » Mon Feb 15, 2010 6:43 am

Oups... sorry, didn't know rapidshare was such a b&#ch with downloads...

I'll try to put ir on the downloads page.

Kayemef · Post by **Kayemef** » Mon Feb 15, 2010 6:50 am

Done, its been sent to the admin approval

t_tangent · Post by **t_tangent** » Mon Feb 15, 2010 3:03 pm

Thanks Kayemef,

Look forward to using them when they are approved by admin

Much appreciated

t_t

Post by **Sharp** » Mon Feb 15, 2010 11:35 pm

I'll be updating the download section tomorrow.

I'm in the Studio here trying to get something done for a client who will be knocking on my door at 10am. lol.... shouldn't even be posting this. Must get back to work.

Sharp.

Kayemef · Post by **Kayemef** » Fri Feb 26, 2010 2:48 pm

Sharp's real busy, so he kindly sent me the link to download the file on the server without having to go through the downloads section.

http://www.korgforums.com/support/oasys/graphs.zip

According to this, you could have an LFO modulate a parameter at 2kHz. I've tried modulating pitches with LFO in order to get something like FM, but at very high values I have a strange feeling that things aren't going exactly as they should under the hood...

Maybe I'm getting too technical, but there's something in Reaktor (and Csound if I remember correctly) called "control rates", in opposition to "sample rates". These control rates are usually much lower than the sample rates used to process audio. They usually, well, sample the control changes...

I was wondering if the O's "control rate" (or whatever its called - the thing that stores the data that represents the LFO) goes up to 2kHz... ?

Kayemef · Post by **Kayemef** » Fri Mar 05, 2010 12:05 am

bump bump...

Anyone at Korg might or might not know the answer to this ?

It's pretty anal on the details but I'm a curious cat :3dread:

And btw, if anyone wonders how you can get an LFO at 2kHz, you just have to set the coarse and fine frequencies of the LFO at 99 - it makes it go at 32Hz. Then using AMS frequency mod at a maximum value multiplies the original frequency by 64. So 32 x 64 goes around 2kHz.

Try using it to do homemade FM or AM... its fun and surprising

Daz · Post by **Daz** » Fri Mar 05, 2010 12:43 am

danatkorg · Post by **danatkorg** » Fri Mar 05, 2010 12:53 am

Kayemef wrote:According to this, you could have an LFO modulate a parameter at 2kHz. I've tried modulating pitches with LFO in order to get something like FM, but at very high values I have a strange feeling that things aren't going exactly as they should under the hood...

Maybe I'm getting too technical, but there's something in Reaktor (and Csound if I remember correctly) called "control rates", in opposition to "sample rates". These control rates are usually much lower than the sample rates used to process audio. They usually, well, sample the control changes...

I was wondering if the O's "control rate" (or whatever its called - the thing that stores the data that represents the LFO) goes up to 2kHz... ?

You're correct that modulation signals often calculated and updated at much lower frequencies (aka sample rates) than audio. Many hardware synthesizers in the digital era used update rates of 16 ms or more. This relatively coarse signal would then be smoothed at audio rates, to reduce stair-stepping.

The OASYS, in comparison, updates envelopes, LFOs, and other modulation signals every two thirds of a millisecond (0.667 ms), again smoothed at the audio rate. That translates to a sample rate of just about 1500 Hz. LFO Frequencies can thus go up to about 750 Hz before they pass above the Nyquist frequency and start to alias. Note that, as you write, this is only possible with extreme modulation of an already fast LFO; the maximum programmable LFO frequency is 32 Hz, less than 1/20 of the Nyquist frequency.

Finally, note that you can do real audio-rate FM in both the MS-20EX and the MOD-7.

Kayemef · Post by **Kayemef** » Fri Mar 05, 2010 6:56 am

Thanks Dan !

I do realize that the best way to do FM is to use, well, an FM synth engine

What's interesting is the fact that these simple LFOs can become very exotic/chaotic tools to create new sounds. Instead of have a classic vibrato assigned to the Y+ axis of the pitch bend joystick, you could have some sort of funky distorted tone changing thing going on...

I've also tried assigning a very, very fast pulse or sample and hold LFO to pitch variations of a few semitones, or even an octave. It gets that cool "SID chip" sound (the one from Internation Karate... aaaaah yeah).

Having that sort of flexibility shows just how much can be done with the Oasys... try doing that with a Fantom.... FACE

Cheers