self-oscillation tuning - posssible?

nextaz · Post by **nextaz** » Wed Mar 25, 2009 7:52 am

Hello

Im unable to tune LP when i want to play with self-oscillatad filter only.
I can tune in one octave only but on whole keyboard no.

Is it possible / is it normal? I must say that oscillators are perfectly in tune but question is about self oscilation only.

Is it possible to callibrate this somehow?

thanks

nextaz

fidooda · Post by **fidooda** » Wed Mar 25, 2009 2:50 pm

i'm no synth expert but i do like to play with the filter this way too.

It's my understanding that the filter oscillates when you do that and not the oscillators. I don't think there's any tuning mecanism for the filter.

Assar · Post by **Assar** » Wed Mar 25, 2009 3:00 pm

You can work with "KB Amount" to get the tunes disposed over the keys correctly. It's a bit tricky but it is possible. I've done it with both my LP and my old Korg Polysix.

nextaz · Post by **nextaz** » Wed Mar 25, 2009 3:43 pm

yes its tricky:) and im able to have correct pitch only in one octave (KB AMOUNT = 3776 and than tune key C with cutoff) thats a problem.

I want to tune it fast like in roland sh9 (check 4:59)
http://www.youtube.com/watch?v=IjhrY5ku4bI

Can other LP users check if they able to tune filter on whole keyboard?

nextaz

Assar · Post by **Assar** » Wed Mar 25, 2009 3:47 pm

Try to set KB Amount to maximum (4095).
What happens then?

nextaz · Post by **nextaz** » Wed Mar 25, 2009 4:14 pm

much worse thats problem - by the way interesting - when i try to max KB AMOUNT it is max on 3826.

4095 is possible but onlu via "precision mode" value knob.

anybody can check this also?

nextaz

Assar · Post by **Assar** » Wed Mar 25, 2009 4:18 pm

Try this patch (for TE) and lower the OSC1 and OSC 2 levels to zero:
http://assar.se/temp/MLPTE99resodistorgan.syx

nextaz · Post by **nextaz** » Wed Mar 25, 2009 8:12 pm

well

here first two keboard octaves are almost in tune (from perfect to max 10+/- ) but third octave is much more untuned.

Do You have every key perfectly in tune here?

And key C is D in this program.

What is other users experience with LP and other analogs?

nextaz

Amos · Post by **Amos** » Thu Mar 26, 2009 9:18 am

The way the filter works, it's not perfectly linear in response to keyboard CV so it's not possible to get it to track more than a couple octaves "perfectly" (or even close).

Your best bet is to set up a self-oscillating filter sound and set kb tracking to 4095 (maximum)... make sure that this is "wide" (one octave on the keys gets you more than one octave change in pitch from the filter oscillations)... then use Precision mode to reduce the KB Amount parameter until your octave is in tune. You can do this across two octaves as well, but you may find that the tuning is somewhat non-linear on the in-between notes. Like, they'll be close, but sharp or flat by a bit from note to note.

If the tuning is not "wide" with KB amount at maximum, pm/email me for further assistance.

Cheers,

Amos

Bryan T · Post by **Bryan T** » Fri Mar 27, 2009 2:45 am

nextaz wrote:when i try to max KB AMOUNT it is max on 3826.

4095 is possible but onlu via "precision mode" value knob.

anybody can check this also?

I noticed the same thing with mine. Is this normal for the KB AMOUNT control?

subtle · Post by **subtle** » Fri Mar 27, 2009 5:49 pm

Excuse me but, what is self oscilliation tuning ?

Bryan T · Post by **Bryan T** » Fri Mar 27, 2009 6:51 pm

subtle wrote:Excuse me but, what is self oscilliation tuning ?

If you turn the resonance of the filter all the way up, then it self-oscillates, creating a tone. By changing the frequency of the filter you can control the pitch.

On the LP you can also control the frequency of the filter using the KB AMOUNT control. It is basically designed to turn up the filter setting when you play higher notes on the keyboard. In this case, you are setting the pitch of the filter frequency and trying to get it to play in tune based on the KB AMOUNT setting.

It isn't perfect, but it is a different way to get sound out of the Little Phatty.

Bryan

EricK · Post by **EricK** » Fri Mar 27, 2009 7:34 pm

You can do the same thing on the Voyager or the MF101 Low Pass filter.

Assar · Post by **Assar** » Sat Mar 28, 2009 5:03 am

http://en.wikipedia.org/wiki/Self_oscillation